HTMS Anatomy (Gross and Clinical) Made easy POOLS
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1. All of the following circulatory changes normally occur immediately at birth EXCEPT:
a) Decreased right atrial pressure
b) Increased blood flow through the lungs
c) Increased left atrial pressure
d) Reversal of flow through the ductus arteriosus
e) Reversal of flow through the foramen ovale
2. A lesion in the supra-marginal gyrus results in the loss of the ability to do all of the following EXCEPT:
a) Read
b) Write
c) Understand speech
d) Speak normally
e) See
3. Which of the following structures passes through the aortic hiatus of the diaphragm?
a) Vagus nerve
b) Esophagus
c) Inferior vena cave
d) Sympathetic trunk
e) Azygos vein
4. Foot drop in usually associated with paralysis of the:
a) Tibial nerve
b) Common peroneal nerve
c) Obturator nerve
d) Medial planter nerve
e) Lateral planter nerve
5. The myelin sheath of a peripheral nerve fiber is formed from:
a) Neural crest cells
b) Schwann cells
c) Oligodendrocytes
d) Neuroepithelial cells
e) Microglia
6. The apex of the heart is formed by the:
a) Left atrium
b) Left ventricle
c) Right ventricle
d) Right and left ventricles
e) Right and left atria
7. An elderly woman visits the hospital emergency room with the recent onset of grotesque swelling of the right arm, neck, and face. Her right jugular vein is visibility engorged and her right brachial pulse is diminished. On the basis of these sign, her chest x-ray might show:
a) A left cervical rib
b) A mass in the upper lobe of the right lung
c) Aneurysm of the aortic arch
d) Right pneumothorax
e) Thoracic duct blockage in the posterior mediastinum
8. All of the following veins drain into the coronary sinus EXCEPT the:
a) Anterior cardiac vein
b) Great cardiac vein
c) Middle cardiac vein
d) Oblique vein of the left atrium
e) Small cardiac vein
9. The major venous return system of the heart, the coronary sinus, empties into the:
a) Inferior vena cava
b) Left atrium
c) Right atrium
d) Superior vena cava
e) Right ventricle
10. The lymphatic vessels of the tongue drain primarily into the:
a) Palatine nondes
b) Deep cervical nodes
c) Gingival nodes
d) Facial nodes
e) Parotid nodes
11. If a patient presents with a permanently dilated pupil, it could be assumed that which one of the following nerves in involved?
a) optic
b) sympathetic trunk
c) ophthalmic
d) oculomotor
e) facial
12. In order to withdraw cerebrospinal fluid (CSF) (i.e., perform a spinal tap, a needle tip must pass successively through the:
a) pia mater, dura mater, epidural space, and arachnoid membrane
b) arachnoid membrane, epidural space, dura mater, and subdural space
c) subdural space, dura mater, epidural space, and arachnoid membrane
d) arachnoid membrane, subdural space, dura mater, and epidural space
e) epidural space, dura mater, subdural space, and arachnoid membrane
13. The ultimate function of the blood-brain barrier is to:
a) exclude small molecules
b) activity transport proteins
c) Keep out white blood cells
d) control the ingress of cholesterol into myelin
e) protect the polarization of the neuronal membrane
14. All venous sinuses of the dura mater ultimately drain into the:
a) external jugular vein
b) internal jugular veins
c) emissary veins
d) carotid sinus
e) great cerebral vein
15. An 18-year-old high school student was brought into the emergency room of a nearby hospital as the result of an automobile accident. In addition to abrasions and facial lacerations, it was found that he had a fracture through the middle of the right arm. Upon neurological examination. It was noted that he was unable to extend his hand at the wrist, or any of his fingers, including the thumb. Supination, flexion and extension of the right forearm and abduction of the right thumb were weakened. Cutaneous innervation was lost over a portion of the posterior aspect of the right arm, over most of the posterior portion of the forearm and over the dorsum of the hand from the thumb to middle finger. The MOST likely diagnosis is injury to the:
a) median nerve
b) radial nerve
c) musculocutaneous nerve
d) ulnar nerve
e) superficial radial nerve
16. An 18-year-old high school student was brought into the emergency room of a nearby hospital as the result of an automobile accident. In addition to abrasions and facial lacerations, it was found that he had a fracture through the middle of the right arm. Upon neurological examination. It was noted that he was unable to extend his hand at the wrist, or any of his fingers, including the thumb. Supination, flexion and extension of the right forearm and abduction of the right thumb were weakened. Cutaneous innervation was lost over a portion of the posterior aspect of the right arm, over most of the posterior portion of the forearm and over the dorsum of the hand from the thumb to middle finger. All of the following muscles would be affected by the injury EXCEPT the:
a) brachioradialis
b) anconeous
c) extensor carpi ulnaris
d) supinator
e) brachialis
17. The adrenal cortex shows a striking zonation. One of these zones, the zone glomerulosa, has cells distinguished by which of the following activities?
a) cortisol secretion
b) mineralocorticoid secretion
c) pregnenolone synthetase
d) 17-alpha-Hydroxlyase activity
e) response to adrenocorticotrophic hormone
18. The ciliary body, located between edge of the retina and the edge of the lens, is characterized by all of the following EXCEPT:
a) an epithelium that contains cones
b) an epithelium that secretes aqueous humor
c) an epithelium that is continuous with the retina
d) ciliary mucles
e) ciliary processes that suspend the lens
19. IN gametogenesis, meiosis differs significantly from mitosis. All the following are characteristics of meiosis EXCEPT:
a) crossing-over occurs between sister chromatids during prophase I
b) daughter cells enter a second M phase of the cell cycle after division I without passing through the G, phase and S phase
c) independent assortment of maternal and paternal genetic material occurs in division I
d) the result of division I is a chromosomal reduction to the haploid number
e) There is pairing of homologous chromosomes
20. At the time of ovulation is the human female, all the following are true EXCEPT that:
a) the first meiotic division has just occurred
b) expulsion of the first polar body has just occurred
c) the secondary oocyte is arrested in the second maturation division
d) the zone pellucida has broken down.
e) Fertilization is possible
21. All the following are characteristics of the plasma membrane EXCEPT:
a) it serves as a selective filtration barrier through the facilitation of both active and passive transport
b) It is possesses a thickness of 1 to 2 mm.
c) It is involved in the generation of ionic gradients between the cytoplasm and the external environment
d) it serves as a sensor of signals from the extracellular environment
e) it has a morphologic appearance similar to that of internal membranes of the cell under electron microscopy
22. Each of the following statements concerning membrane transport proteins is true EXCEPT:
a) integrin is involved is in fibronectin transport
b) erythrocyte band III protein is involved in bicarbonate transport
c) most membrane transport proteins are trans-membrane proteins
d) Na+-K+ AT Pase is involved in cation transport
e) most membrane transport proteins are amphipathic
23. All of the following about cerebrospinal fluid (CSF) are true EXCPT:
a) The general direction of flow of CSF through the brain may be described as: formed in the fourth ventricle; flows through the cerebral aqueduct, third ventricle and lateral ventricles; and exist primarily through the arachnoid granulations
b) The formation of CSF takes places in the choroid plexus
c) CSF is absorbed through arachnoid granulations
d) the ultimate composition of the CSF is dependent to a considerable extent upon the blood-brain barrier,
e) CSF flows into the subarachnoid spaces a the level of the fourth ventricle through several apertures known as the “foramen of Magendia” and foramen of Luchka”
24. The parotid duct penetrates which of the following muscles?
a) Masseter
b) medial pterygoid
c) buccinators
d) superior pharyngeal constrictor
e) levator anguli oris
25. A herniated or prolapsed disc usually occurs in which of following directions?
a) anterior
b) posterior
c) posterolateral
d) anterolateral
e) inferiorly
26. Which of the following structures is MOST important for support of the female pelvic viscera?
a) the supporting fasciae
b) the perivascular staik as a suspensory structure
c) The uterosacral ligament
d) the levator ani muscle
e) the round ligament of the uterus
27. The chief action of the gluteus medius is:
a) extension at the hip joint
b) flexion at the joint
c) medial rotation of the femur
d) abduction at the hip joint
e) adduction at the hip joint
28. Which of the following muscles is both a dorsiflexor and in invertor of the foot?
a) peroneus bravis
b) peroneus longus
c) extensor halluces longus
d) extensor digitorum longus
e) peroneus tertius
29. If cell bodies in the geniulate ganglion are damaged, you would expect the symptoms to be:
a) loss of sensation of pain from the face
b) loss of sensation of touch from the anterior two-thirds of the tongue
c) loss of taster from the anterior two-thirds of the tongue
d) partial facial paralysis
e) none of the above
30. The cerebrospinal fluid enters the venous system:
a) at arachnoid granulations
b) at the cisterna magna
c) through subarachnois veins
d) via capillaries in the ependyma
e) by none of the above routes
31. All of the following structures pass deep to the transverse carpal ligament EXCEPT the:
a) flexor digitorum susperficialis tendon
b) flexor digitorum profundus tendon
c) flexor polices longus tendon
d) median nerve
e) ulnar artery
32. The meeting and union of the mature human sex cells at the fertilization normally occur in the:
a) cervix
b) upper third of the uterine tube
c) fundus of the uterus
d) body of the uterus
e) vagina
33. In the formation of a sperm, part of the Golgi apparatus gives rise to the:
a) acrosome
b) cytoplasmic sheath
c) axial filament
d) neck
e) flagellum
34. The respiratory bronchiole differs from the terminal bronchiole in that the former:
a) lacks cilia
b) contains goblet cells
c) has a small amount of cartilage
d) is lined by ciliated columnar epithelium
e) contains a few respiratory alveoli
35. Bowman’s capsule is formed by the:
a) metanephros
b) ureteric bud
c) pronephros
d) metanephric mesoderm
e) mesonephros
36. A posteriorly perforating ulcer in the pyloric antrum of the stomach is MOST likely to produce initial localized peritonitis or abscess formation in the:
a) greater sac
b) left subhepatic and hepatorenal space (pouch of Morison)
c) Omental bursa
d) right subphrenic space
e) right subhepatic space
37. A 48-year-old woman is brought to the emergency after being found in the part, where apparently she had lain overnight after a fall. She complains of severe pain in the left arm. Physical examination suggests that she has a broken humerus, which is confirmed radiologically. The patient can extend the forearm at the elbow, but supination appears to be somewhat weak; the hand supination appears to be somewhat weak; the hand grasph is very weak when compared with the uninjured arm. Neurologic examination reveals an inability to extend the wrist (wrist-drop). Since these findings point to an apparent nerve damage, these findings point to an apparent nerve damage, the patient is scheduled for a surgical reduction of the fracture. The observation that extension at the elbow appears normal, but supination of the forearm weak, warrants localization of the nerve lesion to the:
a) posterior cord of the brachial plexus in the axilla
b) posterior divisions of the brachial plexus
c) radial nerve at the distal third of the humerus
d) radial nerve in the midforearm
e) radial nerve in the vicinity of the head of the radius
38. As a result of automotive, trauma, a person sustains a complete crush injury of the right half of the spinal cord (Brown-Sequard’s syndrome) at the T12 level, Findings at neurologic examination include:
a) contralateral flaccid paralysis at the level of the lesion
b) contralateral loss of position sense and two-point discrimination below the lesion
c) contralateral loss of light touch below the lesion
d) ipsilateral loss of pain and temperature below the lesion
e) ipsilateral motor paralysis with spasticity below the lesion
39. A lesion of the lingual nerve immediately after if receives the chorda tympani nerve could result in each of the following EXCEPT:
a) loss of sublingual gland secretion
b) sensory loss from lower teeth
c) loss of taste from anterior two-thirds of the tongue
d) loss of submandibular gland secretion
e) sensory loss from mucosa on floor of mouth
40. A patient complaining of tingling and pain down a leg into the little toe would MOST likely have a lesion of which sensory nerve root?
a) L2
b) L3
c) L4
d) L5
e) L1
41. A patient has weakness of his left leg. Your examination shows no muscles stretch reflex at the ankle, severe atrophy of the cell muscles, and loss of sensation over the back of the calf, sole, and lateral aspect of the foot. Most likely he has:
a) an upper motor neuron (UMN) lesion
b) a lower motor neuron (LMN) lesion at the anterior horn cells
c) a cerebellar lesion
d) a primary lesion of muscle
e) peripheral nerve lesion
42. An infection in the nose and medial portion of the eyelid will probably cause enlargement of the _______ lymph nodes:
a) superficial parotid
b) deep cervical
c) occipital
d) retroauricular
e) anterior auricular
43. A macrophage has all of the following feature EXCEPT:
a) an irregularly shaped nucleus
b) many lysosomes
c) many surface projections
d) Few microfilments
e) the ability to engage in active pinocytosis
44. All of the following statements concerning T cells are true EXCEPT:
a) they are similar to B cells when seen with the light microscope
b) they are derived from bone marrow stem cells and require thymosin for their differentiation
c) they are abundant in the thymus and in the spleen
d) they have fewer surface immunoglobulins than B cells
e) they undergo functional maturation in the spleen
45. A pleuripotential cell that passes the checkpoint in G, (i.e., the presence of cytoplasmic S-phase activator) and enters the S phase of the cells cycle will undergo all the following EXCEPT:
a) completion of the cell cycle by undergoing mitosis and cytokineisis
b) continued cycling through mitoses the cell to enter the prolonged interphase Go
c) production of enzymes necessary for DNA replication
d) production of secretory products
e) replication of the complete genome
46. Derivatives of the mesodermal cell layer of the embryo all the following structures EXCEPT the:
a) adrenal cortex
b) gonads
c) peritoneal serosa
d) spleen
e) tonsillar parenchyma
47. All the following are similarities between endocytosis and exocytosis EXCEPT:
a) the fusion of initially separate areas of the lipid bilayer
b) sequestration of material in vesicles
c) selected fusion of membranes
d) involvement of clathrin
e) the adherence of cytoplasmic-side plasma membrane monolayers
48. Which of the following is true by microtubules?
a) Taxol binds to tubulin molecules and prevents polymerization
b) Colchicine binds of microtubules and stabilizes them
c) Taxol and colchicine both function as antimitotic drugs
d) microtubules are usually found in the cytoplasm as large bundies and extensive, cross-linked networks
e) microtubules are highly stable structures that over very slowly
49. All the following statements are true of the endoplasmic reticulum (ER) EXCEPT:
a) it is involved in the synthesis of only exportable protein
b) it is found in all eukaryotic cells
c) it is involved I lipid synthesis
d) it varies in density depending upon the functional activity of the cell
e) it is continuous with the nuclear envelope
50. Of the following cell types, which would contain many mitochondria in the apical portion of the cell?
a) smooth muscle cells
b) ciliated cells
c) steroid-secreting cells
d) liver parenchymal cells
e) skeletal muscle cells
51. Each of the following statements concerning lymph nodes is true EXCEPT:
a) T cells are present in secondary nodules
b) T cells predominate in the deep tertiary complex
c) secondary nodules lack macrophages
d) reticular fibers surround subcapsular sinuses
e) secondary nodules contain reticular fibers
52. Each of the following statements concerning B cells is true EXCEPT:
a) they can differentiate into plasma cells
b) they must interact with macrophages before they produce antibody
c) they are derived from bone marrow
d) they are abundant in secondary nodules
e) they are less common than T cells in the PALS in the spleen
53. Which of the following statements about the blood-brain barrier is correct?
a) it has well-developed capillary pores that allow for selective diffusion of substances
b) it is selectively permeable to certain compounds such as biogenic amines
c) it is found within all structures enclosed by the meninges including the pineal gland
d) tight junctions associated with the blood-brain barrier are formed exclusively by neuronal or glial processes
e) the blood-brain barrier is generally limited highly vascular regions of the brain such as those present at the level of the ventromedial hypothalamus
54. An injury to a patient results in a hemisection of the right half of the spinal cord which extends from T8 to T12. It is probable that the patient will experience:
a) loss of pain and temperature sensation from the right leg; loss of conscious proprioception from the left leg: upper motor neuron paralysis of the left leg
b) loss of pain and temperature sensation from the left leg; loss of conscious proprioception from the right leg; upper motor neuron paralysis of the left leg
c) loss of pain and temperature sensation from the left arm and leg; loss of conscious proprioception from the right leg and arm; flaccid paralysis of the right leg
d) loss of pain and temperature sensation from the left leg and loss of conscious proprioception from the right leg; upper motor neuron paralysis of the right leg.
e) bilateral loss of pain and temperature sensation and conscious proprioception, both from the lower half of the body; upper motor neuron paralysis of the left leg and flaccid paralysis of the right leg
55. The right suprarenal vein drains into which of the following veins?
a) right renal
b) inferior mesenteric
c) superior mesenteric
d) portal
e) inferior vena cava
56. Which of these statements is true in relation to intercostal nerves?
a) in the intercostal space, they run between the internal and external intercostal muscles
b) they are located in the costal groove above the artery and vein
c) they are all confined to the thorax
d) they are entirely cutaneous to the thoracic wall
e) the upper six nerves terminate as anterior cutaneous branches
57. A cerebral vascular accident it eh primary visual area of the left cerebral hemisphere results in:
a) binasal heteronymous hemianopsia
b) bitemporal heteronymous hemianopsia
c) contralateral homonymous hemianopsia
d) ipsilateral homonymous hemianopsia
e) total blindness of the right eye
58. Anesthesia of the maxillary premolar teeth can be effected by infiltrating the nerve as it leaves the:
a) foramen rotundum
b) greater palatine foramen
c) incisive canal
d) infraorbital foramen
e) lesser palatine foramen
59. The striated or brush border is composed of:
a) tightly packed cilia
b) microvilli
c) tightly packed filaments
d) dendrites
e) tonofibrils
60. A patients is diagnosed as having intestinal angina (thrombotic occlusion of the superior mesenteric artery near its origin). If significant collateral circulation is not present or fails to develop, all the following is not present or fails to develop, all the following parts of the intestinal tract may become gangrenous EXCEPT the:
a) ascending colon
b) appendix
c) descending colon
d) ileum
e) transverse colon
61. A physician examines a patient who complains of pain and paresthesia in the left leg. The distribution of the pain-running down to the medial aspect of the leg and medial side of the foot and including the great toe-is suggestive of a herniated intervertebral disc. The physical links the distribution of symptoms with nerve L4 and concludes that herniation has occurred at which location?
a) L3-L4 intervertebral disc
b) L4-L5 intervertebral disc
c) L5-S1 intervertebral disc
d) S1-S intervertebral disc.
e) Insufficient data to determine
62. An injury to the median nerve in the middle third of the arm would affect which of the following muscles?
a) flexor carpi ulnaris
b) adductor pollicis
c) abductor digiti minimi
d) abductor pollicis brevia
e) extensor carpi radialis longus
63. Compression of the median nerve in the carpal tunnel deep to the flexor retinaculum could affect the functioning of each of the following muscles EXCEPT the:
a) second lumbrical
b) opponens pollicis
c) flexor pollicis brevis
d) abductor pollicis brevis
e) flexor carpi radialis
64. A neurosurgeon wishing to eliminate pain in a particular dermatome without causing loss of the sense of touch would make a cut at which one of the following sites?
a) where the lateral fibers of the dorsal root attach to the cord
b) in the midportion of the root as it crosses the subarachnoid space
c) just after the dorsal root enters the subarachnoid space from the interverebral foramen
d) just at the distal edge of the dorsal root ganglion
e) in the nerve trunk about 1 cm distal to the ganglion
65. Recognition of a coin felt in your pocket, but not seen, depends on the:
a) dorsal column pathway
b) spinocerebellar tract
c) spinoreticular tracts
d) ground bundies
e) none of the above
66. All of the following organalles incorporate a unit membrane EXCEPT:
a) ribosome
b) rough endoplasmic reticulum
c) lysosome
d) nuclear envelope
e) Golgi apparatus
67. Which of the following statements is true of cardiac development?
a) during formation of the heart loop, a single-tube heart remains suspended by a complete dorsal myocardium (mesentery).
b) the atria are represented cranial portions of the endocardial tubes
c) the heart bends into a S-shape because the caudal regions of the endocardial tubes grow faster than the cranial regions
d) the left and right sides of the heart the left and right from the side-by-side apposition of the left and right endocardial tubes
e) the sinus venosus becomes incorporated into the atrium prior to the formation of the heart loop
68. Blood from the placenta is about 80% oxygenated. However, mixture with unoxygenated blood at various points reduces the oxygen content. Which of the following vessels contains blood with the highest oxygen contents?
a) abdominal aorta
b) common carotid arteries
c) ductus areriosus
d) pulmonary artery
e) pulmonary vein
69. The plasma membrane can be characterized by:
a) a bilaminar structure in electron micrographs
b) the presence of carbohydrates primarily in the form of free saccharide groups
c) a double layer of lipid that serves as a barrier to water soluble molecules
d) lipids interspersed within protein bilayers
e) hydrophobic outer portion
70. Which of the following statements correctly characterizes membrane protein?
a) content is constant in cells with different functions
b) polypeptide chains can extend across the lipid bilayer once or multiple times
c) protein can be removed entirely from the membrane by mild extraction methods
d) membrane protein includes integral proteins associated with the extracellular surface
e) membrane protein includes peripheral proteins bound to phospholipids in the membrane bilayer
71. Each of the following statements concerning the nucleolus is true EXCEPT:
a) electron microscopy reveals its homogeneous granular structure
b) DNA strands comprise its nucleolar organizer region
c) microbeam irradiation suppresses rRNA synthesis in the nucleolus
d) rRNA synthesis and assembly occur in the nucleolus
e) a cell nucleus may contain more than one nucleolus
72. Each of the following statements concerning the structure of the nuclear envelope is true EXCEPT:
a) it consists of two asymmetrical unit membranes
b) it contains nuclear pores, which have a hexameric substructure
c) macromolecules pass from the nuclear matrix into the cytoplasm through nuclear pores
d) it has 3-40 nuclear pores/mm2
e) unit membranes end abruptly at nuclear pores
73. A patient is unable to move his eyes downward. The lesion is MOST likely situated in the:
a) medulla
b) basilar aspect of the pons
c) pontine tegmentum
d) cerebellum
e) midbrain
74. All of the following statements concerning hair cells of the utricle are he EXCEPT:
a) they are stimulated by deformation of their stereocilia by the otolithic membrane
b) they are stimulated by angular acceleration of the body
c) deformation of the brush pile of the stereocilia and kinocilium in the direction of the kinocilium opens up many channels, leading to a depolarization
d) they are stimulated by tilting of the head or by changing the position of the head
e) deformation of the stereocilia and kinocilium in the direction opposite to that of the kinocilium will result in a hyperpolarization
75. Inability to flex the distal phalanx of the fourth and fifth digits of the hand would indicate damage to which of the following nerves?
a) radial
b) deep radial
c) median
d) anterior interosseous
e) ulnar
76. On the right side a patient shows paralysis of palatal elevation, of the vocal cord, and of the trapezius and sternocleidomastoid muscles. The gag reflex is absent on the right side, and the patient has moderate difficulty swallowing. A site for a lesion that would explain all of these findings is:
a) left cerebellopontine angle
b) right cavernous sinus
c) left pontine tegmentum
d) right jugular foramen
e) right cerebral peduncle and interpeduncular fossa
77. A patient complains of diplopia only when looking up and to the right, the diplopia MOST likely represents weakness of:
a) the right superior rectus or left inferior oblique muscle
b) the right superior oblique or left inferior rectus muscle
c) the right lateral rectus or left medial rectus muscle
d) superior rectus muscle
e) none of the above
78. When a patient cannot adduct the left eye when attempting to look to the right, but the eye adducts on convergence, the lesion is in the:
a) left dorsal longitudinal faciculus
b) right medial lemniscus
c) left medial longitudinal facidiculus
d) left medial forebrain bundle
e) nucleus of CN III
79. All of the following statements concerning B cells are true EXCEPT:
a) they can differentiate into plasma cells
b) they must interact with macrophages before the y can produce antibody
c) they are abundant in secondary nodules in lymph nodes
d) they are derived from bone marrow
e) they are less common than T cells in the periarterial lymphatic sheaths (PALS) in the spleen
80. During development of the heart, the sinus venosus becomes incorporated into other structures. Derivatives of the embryonic sinus venosus include all the following EXCEPT the:
a) coronary sinus
b) smooth-walled portion of the right atrium
c) trabeculated portion of the right atrium
d) valve of the coronary sinus
e) valva of the inferior vena cava
81. The skeletal and connective tissue structures of the lower portion of the face and anterior neck are derived from neural crest cells in the branchial arches. All the following structures derived neck are derived from neural crest cells in the branchial arches. All the following structures derive from the second branchial arch EXCEPT the:
a) lesser horn of the hyoid bone
b) malleus
c) stapes
d) styloid process of the temporal bone
e) stylohyoid ligament
82. Which of the following statements correctly characterizes secretary vesicles?
a) they bud off from the rough endoplasmic reticulum
b) they are primarily involved in the constitutive secretary pathway
c) they contain primarily trans-membrane proteins for addition to the plasma membrane
d) they may be coated with lathrin and its associated coat proteins
e) they serve only as transport structures to the cell membrane; the secretory contents are not modified in these structures
83. True statements regarding phagocytosis include:
a) it occurs constitutively
b) it occurs independently of the cytoskeleton
c) it is generalized membrane response and is not localized to specific regions
d) it occurs by a “membrane-zipper” action
e) it only involves the ingestion of intact prokaryotes and eukaryotes or pieces of them
84. Each of the following statements concerning smooth muscles cells is true EXCEPT:
a) they do not contain sarcomeres
b) they contain stable thick filaments
c) they contain many mitochondria
d) they have gap junctions
e) they do not contain T tubules
85. Thin filaments have all of the following components EXCEPTS:
a) myosin
b) troponin C
c) F-action
d) troponin 1
e) tropomyosin
86. Each of the following statements concerning cardiac muscles cells in true EXCEPT:
a) they have less sarcoplasmic reticulum than skeletal muscle cells
b) they are abundant in the wall of the ventricles and atria
c) they are abundant in the epicardium
d) they contain T tubules
e) gap junctions facilitate ionic communication between cardiac muscle cells
87. All of the following are properties of the choroid plexus EXCEPT:
a) under hydrostatic pressure, it produces CSF
b) it consists of single layer of cuboidal epithelial tissue
c) it contains a barrier to passive to exchange of proteins which is formed by tight junctions surrounding apical regions of the pithelial cells
d) it contributes to the mechanism governing peptide regulation of the pituitary by the hypothalamus
e) an active Na/K pump is present which accounts for the relatively higher concentration of Na+ in choroidal secretions
88. All of the following statements concerning myelin are true EXCEPT:
a) in the peripheral nervous system, myelin is formed from Schwann cells
b) the plasmalemma of the Schwann cells surrounds an axon and spirals around the axon in concentric layers
c) the spaces between Schwann cells will become nodes of Ranvier
d) the same group of proteins are found in myelin of both the central and peripheral nervous systems
e) in oligodendrocytes the genes that encode myelin are “turned on” by the presence of axons
89. If the phrenic nerve was cut close to its origin which of these effects could be seen?
a) loss of bronchoconstriction
b) loss of sensation in the middle diaphragm
c) loss of power in intercostal muscles
d) difficulty in expiration
e) loss of the respiratory reflex arc
90. All the following structures empty into the right atrium of the heart EXCEPT the:
a) coronary sinus
b) inferior vena cava
c) superior vena cava
d) anterior cardiac veins
e) pulmonary veins
91. The gluteus medius and gluteus minimus muscles have similar characteristics EXCEPT:
a) both arise from the ilium
b) both insert on the greater trochanter of the femur
c) both are supplied by the superior gluteal nerve
d) both are particularly important in walking
e) both are strong flexor and medial rotators
92. A typical thoracic vertebral includes all of the following components EXCEPT:
a) a heart-shaped vertebral body
b) inferior articular facts
c) a neural canal
d) superior costal facets
e) transverse foramina
93. In hospital emergency room, a 21-year-old man states that the “inhaled” a peanut. On bronchoscopy the peanut will MOST likely be located in the:
a) left lower lobar bronchus
b) left main bronchus
c) left superior segmental bronchus
d) right lower lobar bronchus
e) right superior segmental bronchus
94. All of the following statements concerning the visual system are true EXCEPT:
a) fibers in the optic tract transmit information from the ipsilateral visual field
b) fibers from the upper retinal quadrants synapse in the medial part of the lateral geniculate body
c) fibers from the medial part of the lateral geniculate body project to the upper lip of the calcarine fissure
d) fibers from nasal retinal fields cross in the optic chiasm
e) fibers from temporal retinal fields remain ipsilateral
95. A lesion of the otic ganglion would be expressed clinically by a loss of:
a) function of the sublingual gland
b) taste on the posterior one-third of the tongue
c) sensory innervation to the parotid gland
d) secretion of the parotid gland
e) function of the stylopharyngeus muscle
96. The chromosomes begin dividing into chromatids during:
a) prophase
b) anaphase
c) early telophase
d) late interphase
e) late telophase
97. Following a tonsillectomy a patient noted loss of general sensation and taste from the posterior one-third of the tongue. It could be assumed that the injured nerve was branch of the:
a) glossopharyngeal nerve
b) facial nerve
c) lingual nerve
d) vagus nerve
e) hypoglossal nerve
98. Bile that is formed by hepatic cells is first secreted into the:
a) bile canalicuil
b) space of Disse
c) bile ducts
d) ampulla of Vater
e) hepatic duct
99. The wall of a terminal bronchiole in the lung contains:
a) plates of hyaline cartilage
b) smooth muscle
c) goblet cells
d) pseudostratified columnar ciliated epithelium
e) mucous glands
100. A 51-year-old man has a paralysis of the right side of his face that produces an expressionless and crooping appearance. He is unable to close his right eye, has difficulty chewing and drinking, perceived sounds as annoylngly intense in his right ear, and experiences some pain in his right eye upon stimulation of either comea and loss of taste from the anterior two-thirds of the tongue on the right side. Lacrimation appears normal in the right eye, the jaw-jerk relflex is normal, and there appears to be no problem with balance. The inability of close the right eye is the result of involvement of:
a) the buccal branch of the facial nerve
b) the buccal branch of the trigeminal nerve
c) the levator palpebrea superioris muscles
d) the superior tarsal muscle (of muller)
e) None of the above
Answers and Explanations
1. The answer is E.
At birth major circulatory changes occur on expansion of the lungs. The resultant increasing blood flow through the pulmonary vascular bed lowers the pressure within the right atrium becomes less than that of the foramen causing the valve of the foramen valve to close. A brief reversal of flow through the ductus arteriosus occurs before this structure constricts as a result of elevated levels of prostaglandins in the blood circulation.
2. The answer is E.
The ability to hear, see, and speak involves several area of the cerebral cortex. The primary sensory and motor cortices are necessary to reactive sensory stimuli and produce motor centers, respectively. In order for the sensory stimuli to have meaning, however, various associative interconnections must be made. These associative functions occur primarily in the partial lobe and include the area of the supermarginal gyrus. Thus, a person with a lesion in and around the supramarginal gyrus would be able to see, hear, feel, and produce sounds. Affected person might not be able to correctly name an object although they know how to use it, or vice versa.
3. The answer is E.
The azygos vein passes through the aortic hiatus of the diaphragm. The other structures listed pass through other openings.
4. The answer is B.
When the common peroneal nerve is paralyzed, when is foot drop, due to the loss of the extensors of the foot, and a turning in of the foot (loss of eversion) due to paralysis of the peroneal muscles.
5. The answer is B.
The Schwann cells form the neurolemma and myelin sheath of nerve fibers in the peripheral nervous systems. Oligodendrocytes form myelin around nerve fibers in the central nervous system.
6. The answer is B.
The apex of the heart is located inferiorly and to the left of the sternum of the fifth intercostal space and is formed by the left ventricle.
7. The answer is B.
The Pancoast’s tumor in the apex of the right lung may compress the right brachiocephalic vein with resultant venous engorgement of the right arm and right side of the face and neck. In addition, there may be compression of the brachial artery, the sympathetic chain, and recurrent laryngeal nerve with attendant deficits. An aneurysm of the brachial arch and could reduce pulse pressures as the great vessels are occluded, but it could not explain the “venous congestion”.
8. The answer is A.
The anterior cardiac vein drain the anterior aspect of the right ventricle directly into the right atrium. The smallest cardiac (thebesian) veins (venae cordis minimae), which drain the endocardiaum, open directly into the various chambers of the heart, principally the atria, but also into the ventricles.
9. The answers is C.
With the exception of the anterior surface of the right ventricle, blood returning from the coronary circulation collects in the coronary sinus, which is turn empties directly into the right atrium. During right ventricular systole, venous blood is stored in the right atrium and during ventricular diastole, blood flows from the right atrium to the right ventricle.
10. The answer is B.
The four major groups of lymph nodes of the tongue (basal, marginal, central, and special) drain directly or indirectly into the superior deep cervical lymph nodes situated along the course of the internal jugular vein.
11. The answer is D.
The oculomotor nerve provides the parasympathetic innervation to the constrictor upillae muscle. Damage to this nerve would result in a permanently dilated pupil, due to the intact innervation of the dilator muscle of the pupil by sympathetic fibers.
12. The answer is E.
The physician can insert of needle into the subarachnoid space to withdraw cerebrospinal fluid (CSF) for diagnostic analysis. The needle tip passes successively through the epidural space, the dura mater, the innermost of the subdural space, and the arachnoid membrane. The CSF is between the arachnoid membrane and the pia mater, the innermost of the three meningeal sheaths.
13. The answer is E.
The untimate function of the blood-brain battier is to protect the surface membrane of the neuron. It excludes a variety of substances that might enter the CNS from the blood and that might alter the electrical potential of the neuronal membrane, casing potential of the neuronal membrane, causing the neuron to function inappropriately. The neuron should function only in response to the appropriate release of neurotransmitters from its synaptic contacts.
14. The answer B.
The venous sinuses of the brain situated either between the two of the dura mater or within reduplications of the meningeal layer of the dura. All sinuses empty directly or indirectly into the beginning of the internal jugular vein located in the jugular foramen.
15. The answer is B.
The fracture has injured the radial nerve in the spiral groove of the humerus and has resulted in the condition known as wrist drop. It has affected the extensors of the forearm and hand a wall as the cutaneous distribution of the cutaneous branches of the radial nerve to the arm, forearm and hand.
16. The Answer is E.
The injury to the radial nerve has paralyzed the medial head of the triceps brachii, and all the extensor muscles of the forearm and hand distal to the injury, including the anconeus, extensor carpi radialis longus and brevis, brachialis, extensor carpi ulnaris, supinator, extensor digitorum, extensor indices extensor digiti minimi, abductor policies longus, extensor polices brevis and extensor pollicis longus.
17. The answer is B.
The zona reticularis and zona faciculata both secrete cortisol, under the influence of adrenocorticotropic hormone (ACTH). A key enzyme in cortisol synthesis, 17-a-hydroxylase, would be expected to occur in both zones. Pregnenolone synthetase is an enzyme active in an early stage of steroid biosynthesis, and its product pregnenolone, is a precursor for the synthesis of many steroids. Thus, pregnenolone synthetase is widely distributed in the adrenal cortex. Aldosterone, a mineralorticoid, is synthesized in the zona glomerulosa.
18. The answer is A.
The ciliary body is covered by a double-layered epithelium. This epithelium is continuous with the retina but lacks photoreceptors, characteristic of the more posterior part of the retina. Also, the ciliary epithelium secretes the aqueous humor, Many long ciliary processes project from the ciliary body toward the lens. The major components of the ciliary body, however, are the ciliary musles. Cones are found in the retina, not in the ciliary body.
19. The answer is D.
Gametogenesis uses meiosis to admix the parental genetic material and to produce a haploid gamete. There is pairing of homologous chromosomes and chromosomal duplication during prophase I. The paired homologues align in the metaphase and crossing-over occurs between sister chromatids. Also at this stage the independent assortment of maternal and paternal genetic material occurs. Because the chromosomes replication results in a tetraploid chromosomal number, division I produces cells with the diploid number. After division I the daughter cells enter a second M phase of the cell cycle without passing through the G1 phase and S phase. Thus, the result of division II is a chromosomal reduction to the haploid number.
20. The answer is D.
At the time of ovulation, the zona pellucida is intact, and it is maintained around the viable secondary oocyte for aproximately5 days. Prior to ovulation, the first meiotic division occurs, with reduction of the chromosomal number to the haploid condition and expulsion of the first polar body. The resulting secondary ooctye immediately proceeds as a far as the spindle stage of the second maturation division. At this time ovulation occurs, and the secondary oocyte may be fertilized. Once a spermatozoon penetrates the corona radiata and comes into contact with the zona pellucida, it becomes firmly attached and begins to penetrate this layer with the aid of enzymes located in the acrosomal cap. The penetration of the zona-pellucida breached, the plasma membranes of the spermatozoon sperm nucleus moves into the oocyte cytoplasm. The secondary oocyte then finishes its second maturation division and gives off the second polar body before the nuclear materials combine. The zona pellcida is maintained until implantation is imminent, about 5 to 6 days.
21. The answer is B.
Cell membranes range in thickness from 7 to 100 nm (1 mm = 109 m; the diameter of a red blood cell is 7mm). A cell membrane surrounds all eukaryotic cells and subserves a number of essential functions. The plasma membrane forms a boundary to the external environment and contains a large variety of receptors that function as ligands for hormones, growth factors, cytokines, and other extracellular factors. It is selective barrier that controls the entry and exist of substances to and from the cell. The plasma membrane and the internal membranes of the cell-such as those surrounding organelles like the nucleus and mitochondria are similar in their morphologic appearance under electron microscopy. The ganellar membranes are usually thinner and differ in overall biochemical composition from that of the plasma membrane.
22. The answer is A.
Erythrocyte band III protein has a hydrophilic core for ion transport and is involved in bicarbonate transport. Na+ K+ ATPase uses energy stored in ATP to maintain the surface potential differences between the cell’s inner and outer surfaces and is involved in cation transport. Most membrane proteins are amphipathic. Transmembrane proteins such as integrin span the entire membrane. They have hydrophilic domains associated with the water inside and outside the cell. They also have a hydrophobic domain associated with the hydrophobic portions of phospholipids. Integrin is membrane receptor for extracellular matrix molecules such as fibronectin and laminin. It binds with extracellular fibronectin to anchor the cell to the extracellular matrix, but it does not transport fibronectin.
23. The answer is A.
The general flow of CSF is from the lateral ventricle, where most of the CSF is produces from the choroid plexus, down through the third ventricle, cerebral, aqueduct, and fourth ventricle where it exist the brain through the foramina of Luschka and foramen of Magendie into the subarachnoid space. CSF is also absorbed into the superior sagittal sinus and other venous structures through arachnoid granulations, which appear as herniations of the arachnoid membrane. Since CSF and extracelluar fluids of the brain are in equilibrium, changes in the blood-brain barrier will alter this equilibrium. Such effects become apparent in certain diseases states. For example in the case of multiple sclerosis, gamma globulin content of the CSF increases to more than 13% of total protein and can be used as a diagnostic indicator.
24. The answer is C.
Crossing the masseter muscle and the buccal fat pad, the duct turns deeply at the anterior border of the buccal pad of fat and penetrates the interior of the mouth opposite the second upper molar tooth.
25. The answer is C.
A herniated or prolapsed disc usually occurs in a porterolateral direction, where the annulus fibrosus is weakest and poorly supported by the posterior longitudinal ligament. The protruding part of the nucleus pulposus may compress an adjacent spinal nerve root, causing leg and low back pain.
26. The answer is D.
The thick pubic parts of the levator ani form a puborectal sling for the rectum, drawing it forward until it forms a sloping shelf. Upon this shelf the vagina rests, and on the vagina rests the bladder. This is the essential support. The pubic parts of the levator ani also insert into the perineal body and thus act as a sling for the posterior wall of the vagina. The urogenital diaphragm and its fascias blend with the lower third of the vagina and assist the levator and to support it.
27. The answer is D.
The chief action of the gluteus medius is abduction of the free limb. More importantly together with the gluteus minimus, it keeps the contralateral side of the pelvis from sagging markedly when the weight of the body is put upon one limb; therefore these muscles are exceedingly important in walking. Only the gluteus minimus is active in flexion and medial rotation of the femur. Apparently the gluteus medius assists with extension and lateral rotation of the femur. Apparently the gluteus medius assists with extension and lateral rotation of the movements. It is not a chief actor in the movements of adduction, medial rotation, or flexion at the hip joint.
28. The answer is C.
The extensor hallucis lonus primarily is an extensor or the big toe but also it is in a position to dorsiflex, adduct, and invert the foot. The extensor digitorum longus and the peroneus tertius also dorsiflex the foot but are located more laterally, so that instead of inverting, the peroneous longus and brevis both evert the foot. They are also planter flexors instead of dorsiflexors.
29. The answer is C.
The geniculate ganglion, the equivalent of a dorsal root ganglion, contains the cell bodies of the sensory neurons of the facial nerve (CN VII). Selective damage to these neurons, results in loss taste sensation from the anterior two-thirds of the tongue. The motor division of the facial nerve supplies the muscles of facial expression.
30. The answer is A.
Cerebrospinal fluid is secreted by the choroid plexuses of the lateral ventricles, the third ventricle, and the fourth ventricle. It circulates through the ventricles and enters the sub-arachnoid space through the fomania of Luschka and Magendie in the roof of the fourth ventricle. The cerebrospinal fluid enters the superior sagittal sinus via arachnoid granulations.
31. Answers is E.
The ulnar nerve and ulnar artery pass deep to the volar carpal ligament but superficial to the transverse carpal ligament. The median nerve is the only major neurovascular structure that passes through the carpal tunnel.
32. The answer is B.
It is generally believed that fertilization, the meeting and union of the human germ cells, occurs in the upper third of the uterine tube.
33. The answer is A.
The sperm head arises from the nucleus of the each spermatid. Part of the Golgi apparatus within the nucleus becomes the acrosome and constitutes and head cap covering the apical half of the head.
34. The answer is E.
The respiratory bronchiole differs from the terminal bronchiole in having a few pulmonary alveoli in its wall. It also has cuboidal epithelium between the alveoli. Cilia are present in the proximal portion, but not distally. Smooth muscle fibers and elastic fibers are well developed. Cartilage and glands are lacking.
35. The answer is E.
The tubules of the mesonephros lengthen and form the Bowman’s capsule at one end of the tubules.
36. The answer is C.
The omental bursa (lesser sac) is the remnant of the right coelomic cavity, which, owing to rotation of the gut and differential growth of the liver, lies behind the stomach. A posterior gastric perforation or an inflamed pancreas could lead to abscess formation in the lesser sec. The right subhepatic space might become secondarily involved via communication through the omental foramen (of Winslow). The pouch of Morison, which is the combined right subhepatic and the hepatorenal spaces, may be the seat of abscess formation related to gallbladder disease or perforation of a duodenal ulcer. The right subphrenic space is between the liver and the diaphragm and communicates with the pouch of Morison. All these spaces are in communication with the greater sac of the peritoneal cavity.
37. The answer is C.
The clinical sings and findings in the patient presented in the question indicate radial nerve damage. The evidence that extension at the elbow appeared normal while supination appeared weak can be used to localize the lesion. The innervation to the medial and long heads of the triceps brachii, principal extensor of the arm, arises from the radial nerve (in the axilla) as the medial muscular branches; the innervation to the lateral head, and to a smaller portion of the medial head, arises from the radial nerve as it passes along the musculospiral groove at mid-humerus. The supinator muscle is innervated by muscular twigs from the deep branch of the radial nerve in the reaches the supinator muscle. Thus, pralysis of the supinator muscle, but not of the triceps brachii, localizes the fracture to the distal third of the humeral shaft between the elbow and musculosipral groove.
38. The answer is E.
Brown-Sequard’s syndrome is a consequence of injury to the posterior funiculus (position sense and two-point discrimination), the anterolateral tracts (pain and temperature), and the pyramidal tracts (motor function)- all on one side. The pyramidal tracts have already crossed that spastic (upper motor neuron) paralysis occurs below the lesion on the ipsilateral side; flaccid (lower motor neuron) lesion. The posterior funiculus contains uncrossed proprioceptive and tactile fibers so that damages produces ipsilateral loss position sense and two-point tactile discrimination at and below the level of injury. The anterolateral tract contains crossed pain and temperature fibers so that injury produces contralateral loss of these modalities at and below the level of the lesion. Multiple crossed and uncrossed tracts convey simple touch so there is little loss of this modality, except at the level of injury.
39. The answer is B.
The lingual nerve is sensory from the mucosa on the floor of the mouth and lingual gingiva. After receiving the chorda tympani the lingual nerve conducts secretory fibers to the submandibular and sublingual glands and taste fibers from the anterior two-thirds of the tongue. The mandibular teeth are innervated by the inferior alveolar nerve.
40. The answer is E.
The patient who complains of tingling and pain into the little toe would most likely have a lesion of the S1 nerve root. The L5 nerve root typically innervates the big toe. The most common cause would be compression of the nerve root by herniated intervertebral disc. Thus, the clinicial localization of the complaint implicates the nerve root that is involved the lesion.
41. The answer is E.
Loss of sensation over a restricted region of skin in association with severe atrophy of the muscles in the region generally suggests a lesion of a peripheral sensorimotor nerve. Lesions of any of the other components of the motor system listed would not cause loss of sensation. A primary lesion or diseases of muscle would not cause a sensory loss.
42. The answer is A.
The superficial parotid nodes drain the external ear, external acoustic meatus, the eyelids, skin of the temporal and frontal regions, lacrimal gland, cheek and nose. These nodes drain into the superior deep cervical nodes.
43. The answer is D.
As part of its motility system, a macrophage has numerous microfilaments. Since it is in active phagocyte, this cell also has many lysosomes and surface projections and is active in pinocytosis. A macrophage has in irregularly shaped nucleus.
44. The answer is E.
T Cells undergo functional maturation in the thymus, where they are stimulated to differentiate by the thymic hormone, thymosin. T cells do not undergo functional maturation in the spleen, but they are abundant there are in the thymus.
45. The answer is D.
The cell cycle consists of four distinct phases. The brief mitotic (M) phase is subdivided into prophase, metaphase, anaphase, and telophase. Telophase is followed by the so-called gap 1 (G1) phase, which is characterized by growth of the cell accompanied by active ribonucleic acid (RNA) and protein synthesis. The synthesis (S) phase in one of DNA synthesis and assembly. During the subsequent gap 2 (G2) phase preparations occur for the impending mitotic, or divisional, phase. As long as cells are induced to cycle, they will produce only products needed for this function. When cells fail to pass the owing to signals in the microenvironment, they enter the cells may differentiate and become specifically functional. The more highly differentiated a cell becomes with respect to morphology (such as nerve cells), or specific protein content (such as muscle), less likely it is to revert to the cell cycle.
46. The Answer is E.
Mesoderm form a wide variety of adult tissues. Serous membranes, the spleen, and the gonads are derived from mesoderm. Other tissues of mesodermal origin are blood vessels, heart, bone, cartilage, skeletal and smooth muscle, skin excretory units of the urinary system, adrenal cortex, and vas deferens. The endodermal germ layer initially forms the epithelial lining of the primitive gut, but later in development it give rise to the following: the epithelial lining of the respiratory tract; the parenchyma of the tonsil, thyroid, parathyroid, thymus, liver and pancreas; the lining of the tympanic cavity and Eustachian tube; and the epithelial of the urinary bladder and urethra.
47. The answer is E.
Although endocytosis and exocytosis may be considered opposites, they have many similarities. Both required the fusion of initially separate areas of the lipid bilayer, which involves apposition followed by fusion of the bilayers to form a vesicle (endocytosis) or to fuse vesicle with plama membrane (exocytosis). In both cases there is sequestration - of secretory product in exocytosis and of ingested material in endocytosis. There is also selected fusion of membranes in that only certain membranous structures will fuse with the next compartment of the endocytic or exocytic pathways. For example, in the case of the exocytic pathway, transition vesicles from the endoplasmic reticulum fuse with cistenae of the cis-Golgi. Clathrin is involved in the both the exocytic pathway form of the hormones - e.g., proinsulin to insulin) and the endocytic pathway in the formation of coated pits and vesicles. In exocytosis, two cytoplasmic-side monolayers of the plasma membrane adhere; in endocytosis, two external surface - side monolayers of the plasma membrane adhere.
48. The answer is C.
Microtubules are labile cytoplasmic strucures capable of very rapid assembly and disassembly. There are a number drugs that inhibit mitosis. Colchicine inhibits the addition of tubulin molecules to microtubules and therefore induces depolymerization of microtubules. Vinblastine also causes microtubules depolymerization through the formation paracrystalline aggregates of tubulin. Taxol stabilizes microtublues by binding rightly to them and induces tubulin to form microtubules. Microtubules differ from microfilaments, which are often found in bundles with extensive cross-linking, comparison, microtubules are often found singly in the cytoplasm.
49. The answer is A.
The endoplasmic reticulum (ER) is found in all eukaryotic cells and may represent more than 50% of the total membrane of the cell. It is a membrane-bound organelle that varies in sizes depending upon the functional activity of the cell. ER may be classified as rough (RER) or smooth (SER). RER is associated with ribosomes involved in the synthesis of proteins for export but also integral membrane proteins and proteins that constitute the membranes of mitochondria and peroxisomes.
SER is involved in lipid synthesis and is extensive in cells actively involved in the lipid production, such as the cells of the adrenal cortex. It may be induced in other cells such as hepatocytes by the systemic administration of drugs such as Phenobarbital. Therefore, in the case of both the SER and RER, the amount of ER varies with the metabolic activity of the cells.
50. The answer is B.
Mitochondria typically exist in cell areas that use substantial amount of ATP. They are abundant in the apices of ciliated cells because the beating action of cilia consumes ATP. They also exist in apices of cells that have a microvillous brush border (e.g., certain kidney cells), because solute transportation and pinocytosis of proteins in the glomerular filtrate consume energy and, therefore, required ATP. Mitochondria are distributed evenly throughout the cytoplasm of smooth muscle cells, steroid-secreting cells, skeletal muscle cells, and liver parenchymal cells rather than existing in apical concentration.
51. The answer is C.
Lymph nodes are filters for antigens in lymph. They contain B cells in primary and secondary nodules and T cells in the deep tertiary cortex. Secondary nodules contain germinal centers, which are sites where B are activated and differentiated into immunologulin secreting plasma cells. Thus secondary nodules contain B cells, helper T cells, suppressor T cells, and macrophages. Reticular gives exist throughout lymph nodes, including around the subcapsular sinsuses and in nodules.
52. The answer is B.
B cells are derived from bone marrow stem cells and commonly differentiated into antibody-synthesizing plasma cells after interacting with helper T cells and macrophages. However, memory B cells can differentiated into plasma cells without interacting with macrophages. B cells are abundant in secondary lymph nodules but are outnumbered by T cells in the PALS.
53. The answer is B.
The blood-brain barrier is selectively permeable to certain types of substances such as biogenic amines and not to others. The barrier is formed by the tight junctions consisting of capillary endothelial cells that are frequently in contact with the glial end-feet of astrocytes. The barrier does not contain well-circumventricular organs such as the subfornical organ and the pineal gland but is applied to all other brain tissues.
54. The answer is D.
Hemisection of the right side of the spinal cord involving segments T8 to T12 will result in contralateral loss of pain and temperature sensation below the level of the lesion and ipsilateral loss of conscious proprioception below the level of the lesion. Thus, this patient will experience loss of pain and temperature in the left leg and loss of conscious proprioception in the right leg. In addition, there will be damage to the descending corticospinal fibers that normally are essential for activation of the lower motor neurons controlling muscles of the right leg (i.e., upper motor neuron paralysis of the right leg). However, since the lesion is situated below the entry of sensory fibers as well as the origin of anterior horn cells that innervate the upper limbs, no loss of sensation to the upper limbs will ensue, nor will there be a lower or upper motor neuron paralysis of the fibers ipsilateral to the sit of the lesion are unaffected because the second-order neurons decussate at the approximate level or their cells bodies of origin and ascend on the side contralateral to the lesion, leaving this system intact.
55. The answer is E.
The right suprarenal vein empties directly into the posterior surface of the inferior vena cava. On the left side (after union with the inferior phrenic vein) it is tributary of the renal vein.
56. The answer is E.
Intercostal nerves are example of typical spinal nerves; the second through the six intercostals are confined to the thorax. The seventh to the 11th intercostals and subcostal nerve continue into the abdominal wall. The upper six intercostal nerves follow the curve of the ribs and costal cartilages toward the sternum and terminate as anterior cutaneous branches. The nerves run in the costal groove of the intercostal space between the internal and innermost intercostal muscles.
57. The answer is C.
Because the optic projections to the visual cortex contain fibers that convey information from the contralateral fields, loss of the primary visual area on one side produces loss of the same contralateral visual field in each eye - contralateral homonymous hemainopsia.
58. The answer is A.
The maxillary premolar teeth are innervated by the middle-superior alveolar nerves. These teeth can be anesthetized by infiltrating the maxillary nerve as it exits through the foramen rotundum into the pterygopalatine of fossa.
59. The answer is B.
If one examines the columnar epithelium of certain organs under the light microscope, a characteristic vertical striation is noted at the free surface. This is called a brush or striated border. Under the electron microscope, the brush border is resolved into numerous cylindrical cell processes which are called microvilli. Microvilli most numerous on cells where are involved in absorption.
60. The answer is C.
The superior mesenteric artery supplies the terminal portion of the duodenum and ileum, appendix, ascending colon, and transverse colon. The inferior mesenteric artery supplies to descending colon sigmoid colon, and the proximal portions of the rectum. While there are usually profuse anastomoses between the superior pancreaticoduodenal branch of the superior mesenteric, there may be scant anastomoses between the left branch of the middle colic and the ascending branch of the left colic.
61. The answer is A.
The deep incisures in the inferior border of the pedicle ensure that the spinal nerves associated with that vertebra will exit through the intervertebral foramen well above the intervertebral disc so that it will not be affected by herniation at that level. However, a posterolateral herniation (the usual direction) will impinge upon the next lower never as it courses toward its associated intervertabral foramen. In this case, pain was distributed along the medial side of the leg and foot as far as the great toe-the distribution of the saphenous branch of the femoral nerve (L4). Herniation of the third lumbar intervertebral disc between vertebral bodies L3-L4 would affect level L4.
62. The answer is D.
Injury to the median nerve in the middle of the arm would affect the pronator teres, pronator quadratus, flexor carpi radialis, opponens pollicis, abductor pollicis brievis, lateral two lumbicals, flexor digitorum superficial, radial half of the flexor digitorum profundus, and the flexor polices brevis muscles.
63. The answer is E.
Distal to the carpal tunnel, the median nerve innervates the three muscles of the thenar compartment and the first two lubrical muscles.
64. The answer is A.
The dorsal roots divide into medial and lateral bundles. The lateral bundle, which consists of small, poorly myelinated fibers mediates pain and temperature Neurosurgeons have attempted to treat some types of chronic pain by selective section of these roots just where they attach to the cord, leaving the larger, heavily myelinated touch and proprioceptive fibers of the medial division of the root intact. Elsewhere in the nerve root and trunk, the fibers intermingle too much to permit selective sectioning.
65. The answer is A.
Recognition of an object felt but not seen requires superficial and deep sensation. The superficial sensation gives information as to temperature, whereas the deep sensation, which travels through dorsal column pathways, provides a sense of form a stereognosis. The brain integrates these pieces of information to identify an object felt by the fingers.
66. The answer is A.
Most of the organelles in the body are composed, at least in part, of unit membranes. The ribosome, however, is not composed of unit membranes. Ribosomes can attach to the unit membranes of the rough endoplasmic reticulum.
67. The answer is C.
The heart forms during the third week by the apposition of left and right endocardial tubes as the head fold progresses caudally. The endocardial tubes fuse to form a single-tube heart. This fusion begins cranially in the region of the bulbus cordis (outflow trunks) and proceeds caudally through the ventricles and the atria to the sinus venosus, which is incorporated into the atrium after loop formation. Rapid proliferation of the ventricular region results in the single-tube heart’s bending into an S-shaped loop. During this process, the dorsal mesocardium partially breaks down, which leaves the heart suspended only at the cranial and caudal ends; the discontinuity in the mescocardium is the transverse sinus. The left and right sides, of the heart are established by the subsequent division of the single-tube heart, not by the apposition of left and right endocardial tubes.
68. The answer is B.
Blood from the placenta n the umbilical vein is about 80% oxygenated. Mixture with unoxygenated blood from the vitelline veins and the inferior vena cava reduces the oxygen content somewhat. However, this stream with a relatively high oxygen content is directed by the valve of the oxygen content is directed by the valve of the inferior vena cava. Thus, the oxygen-saturated blood entering the left ventricle and pumped into the aortic arch, sub-clavian arteries, and common carotid arteries has the highest oxygen content. The oxygen-depleted blood from the superior vena cava is directed into the right ventricle and hence to the pulmonary trunk. While a small portion of this flow passes through the lungs (where any residual oxygen is extracted by the tissue of the non-respiring lung), most is shunted into the thoracic aorta via the ductus arteriosus and thereby lowers the oxygen content of the vessel. This occurs distal to the origins of the carotid arteries and ensures that the rapidly developing brain has the best oxygen supply.
69. The answer is C.
The plasma membrane is visualized as a trilaminar structure in electron micrographs in which the lipid bilayer is stained with osuium. The trilaminar membrane is the classic form the membrane whether one is viewing the plasma membrane or the membrane surrounding the intracellular organelles. The two dense lines with a light line in between give the appearance of a railroad track. The membrane actually consist of a bilayer of phospholipids with the nonpolar, hydrophobic layer in the central portion of the membrane. The outer portion of the membrane is, therefore, hydrophilic as the polar regions of the phospholipids are in contact with aqueous components at the intra-or extracellular surfaces of the membrane. This lipid bilayer is responsible for the impermeability to water-soluble molecules that is exhibited by found in the membrane in the form of glycolipids and glycoproteins. Proteins are generally interspersed within the lipid bilayer.
70. The answer is B.
Membrane protein is the variable portion of the cell membrane. The average protein mass in membranes is about one-half but varies from one-fourth to three-fourths depending upon cell function. Polypeptide chains that constitute trans-membrane proteins may be single-pass or multiple-pass molecules as they cross the membrane from the cytosolic to the extracellular from the cytosolic to the extracellular side. Some proteins may be removed from the lipid bilayer through mild extraction techniques that alternation of surface charge of pH. These proteins are the peripheral (extrinsic) membrane proteins associated the integral (intrinsic) membrane proteins are bound tightly to components of the phospholipid bilayer and require detergent treatment for removal from the membrane.
71. The answer is A.
The nucleolus is a structure within the nucleus of many cells. An electron microscopic view of the nucleolus reveals that it has a fibrillar component that contains strands of DNA and a granular component that contains ribosome precursors. The DNA strands comprise the nucleolus organizer region, which contains the genes necessary for rRNA synthesis. Within the nucleolus, rRNA synthesized and assembled into ribonuclear protein particles (ribosome precursors), which in turn, are assembly into ribosomes. Then, ribosomes are transported through nuclear pores into the cytoplasm. When the nucleolar organizer region is subjected to ultraviolet microbeam irradiation, rRNA synthesis stops and the nucleolus disappears.
72. The answer is B.
The nuclear envelope completely surrounds the nucleus, forming a boundary between the nucleoplasmic matrix and the cytoplasm. It consist of two closely apposed asymmetrical unit membranes, which contain several hundred octameric nuclear pores. The nuclear envelope end abruptly at each nuclear pore. The outer membrane is studded with ribosomes and is continuous with the rough endoplasmic reticulum. The inner membrane is thicker than the outer membrane. The inner face of the inner membrane has a fibrous substructure composed of strands of chromatin, which is involved in regulating the diameter of nuclear pores. Each square micrometer of nuclear envelope surface contains 3 - 40 nuclear pores.
73. The answer is D.
Inability to move the eyes to a downward position may result from a lesion of cranial nerve IV (when the eye is positioned medially) or cranial nerve III (when the eye is positioned laterally). In either case, the cell bodies of origin of these cranial nerves are located in the midbrain.
74. The answer is B.
Very fine filaments connect the tip of each stereocilia to the next and these cilia project upward into the gelatinous layer in which calcium carbonate crystals (i.e., statoconia) are embedded. When the head is suddenly tilted or the position of the head is suddenly change, the statoconia, which have greater inertia than the surrounding fluids, are moved backward onto the cilia. Deflection of the stereocilia in the direction of the kinocilium causes an opening of channels for conducting sodium ions. Hyperpolarization occurs when the stereocilia are bent in the direction opposite to that of the kinocilium in which case tension on the attachments is reduced, which results in the closing of sodium channels. Hair cells of the utricle are not stimulated by angular acceleration. This type of stimulus is effective, however, in activating receptors in the semicircular canals.
75. The answer is E.
In the forearm, the ulnar nerve innervates the flexor carpi ulnaris and the ulnar half of the flexor digitorum profundus. This latter muscle flexes the distal phalanx of the fourth and fifth digits.
76. The answer is D.
CN IX, CN X, and CN XI exist from the skull through the jugular foramen. A lesion at that foramen would interrupt all three nerves and paralyze the ipsilateral palatal, pharyngeal, sternocleidomastoid, and trapezius muscles. This is one example of several syndromes that occur when a conjunction of cranial nerves at the base of the skull.
77. The answer is A.
When the eyes look conjugately in any direction the muscle that is the prime mover of the leading eye acts in unison with (is yoked to) a muscle of the following with eye, which corresponds. Both muscles receive equal innervation in order to move the eyes equally and maintain the visual axes of both eyes on the target, thus avoiding diplopia. On looking upward and to the right, the right superior rectus muscle is yoked to the left inferior oblique muscle.
78. The answer is C.
When an eye fails to adduct on voluntary horizontal gaze, but it does adduct during convergence, the lesion is in the medial longitudinal fasciculus. This bundle conveys the voluntary pathway from in the nucleus of CN VI (or surrounding region in the pons) to the nucleus of CN III. A lesion of the lower motor neurons (LMNs) in the nucleus of CN III would paralyze adduction during volitional movements and convergence.
79. The answer is C.
Memory B cells can differentiate into plasma cells without mediation by macrophages. B cells are derived from bone marrow stem cells and commonly differentiate into plasma cells. with the help of helper T cells and macrophages. B cells are abundant in secondary nodules in lymph nodes and are less common than T cells in the periarterial lymphatic sheaths.
80. The answer is C.
By the end of the first month of development the sinus venosus receives the vitelline veins, umbilical veins, and the common cardinal veins, thereby returning blood to the heart from the intreambroyonic and extraembryonic portions of the embryo. Early in the second month of development, the left horn of the sinus venosus becomes the coronary sinus and also contributes the valve of the coronary sinus. The right horn becomes incorporated into the right atrium as the smooth-walled (sinus venarium) portion. This is separated from the original trabeculated common atrium by the crista terminalis. The right horn also gives rise to the valve of the inferior vena cava.
81. The answer is B.
The cartilage of the first pharyngeal arch consists of a maxillary process and a mandibular process. During development both cartilages regress, except for two portions at the dorsal ends that persist as the incus and the malleus. The cartilage of the second (hyoid) arch gives rise to the stapes, the stylohyoid ligament, and the lesser horn of the hyoid bone. The body and greater horn of the hyoid bone. The body and greater horn of the hyoid bone are derivatives of the third brachial arch.
82. The answer is D.
Secretory vesicles bud off from the trans-Golgi network (TGN) of the Golgi apparatus and transport primarily exportable proteins to the plasma membrane for exocytosis. They are responsive to secretory stimuli and secretagogues and therefore function within the regulated secretory pathway. In contrast the constitutive secretory pathway. In contrast, the constitutive secretory pathway is involved in the continual transport of trans-membrane proteins and lipids to the plasma membrane for replacement of membrane proteins. The secretory product and in the case of some peptides to convert precursors to active form (e.g., proinsulin to insulin). Both the concentration process and the conversion of precursors to active forms of peptides appear to involve acidification through a proton pump mechanism in the membrane of the secretory vesicles. When secretory vesicles bud off from the TGN, they may be coated with clathrin and its associated coat proteins. The clathrin-coated vesicle is denuded of the clathrin coating during the concentration process within the secretory vesicles.
83. The answer is D.
Phagocytosis is the process of ingestion of large structures by the cell. The process is triggered by the presence of certain particles at the cell surface; it is not a constitutive mechanism and only occurs in regions of the cell in contact with the substance to be ingested. Agents that disrupt actin polymerization, such as cytochalasin, block phagocytosis by prevention of the formation of macrophage pseudoponds and indicate the importance of the cytoskeleton in phagocytosis. Antibodies are the best example of a stimulus for the phagocytic ingestion by macrophages and phagocytic cells. Adhesion in this case is the recognition and binding of lgG to Fc receptors on the macrophage. The binding of ligand to receptor is probably with the initiation to changes in the cytoskeleton that lead to phagocytosis. “Membrane-zippering” is involved in phagocytosis since continuous contact of the antibodies with the Fc receptors is required for the pseudopond to surround the particle to be ingested. If the lgG molecules are limited to a specific region of the antigen, then there is contact but no ingestion. Inert as well as biologic materials are ingested by macrophages. Therefore, latex beads, Indian ink and trypan blue are phagocytosed by macrophages when these substances are injected into the body or provided in the medium surrounding cells in vitro.
84. The answer is B.
Smooth muscle is abundant in the gastrointestinal and reproductive systems. Smooth muscle contraction controls the peristaltic motility in the organs of these systems. Smooth muscle cells do not contain sarcomeres or T tubules, but they do contain many thin filaments, labile thick filaments, and numerous mitochondria, which produce the ATP for muscle contraction. Gap junctions join cells and coordinate muscle contraction.
85. The answer is A.
All types of muscle tissue contain thin filaments, which consist of F-actin cables and the regulatory proteins tropomyosin and troponin. Troponin is complex of troponin C, troponin T, and troponin I.
86. The answer is C.
Cardiac muscle cells are present throughout the myocardium and the proximal roots of the venae cavae and pulmonary arteries; they are not present in the epicardium. Like skeletal muscle cells, cardiac muscle cells contain prominent sarcomeres, sarcoplasmic reticulum, and T tubules; however, they have less sarcoplasmic reticulum than skeletal muscle cells are joined by intercalated discs containing numerous gap junctions with aqueous channels for intercellular ionic communication.
87. The answer is D.
The choroid plexus, which consists of a single layer of cuboidal epithelial cells, produces cerebrospinal fluid under hydrostatic pressure. The barrier to passive transport or exchange of proteins and certain other substances such hydrophilic solutes is formed by the tight junctions connecting apical regions of these epithelial cells. The fact that choroidal secretions contain relatively higher Na+ and relatively lower K+ is accounted for by an active sodium-potassium pump. Peptide regulation of pituitary functions is unrelated to the general functions of the choroid plexus.
88. The answer is E.
In the peripheral nervous system. Schwann cells are responsible for producing myelin, while in the CNS, this function is carried out by oligodendrocytes. The myelin present along nerve fibers in both the peripheral and central nervous systems referred to as “myelin basic portions. ”Myelin is formed when the plasmalemma of around the axon in concentric layers. The nodes of Ranvier are spaces between Schwann cells where the axon is unsheated. On major difference between Schwann cells are oligodendrocytes int eh Schwann cell genes that node myelin are “turned on” by other Schwann cells, while the genes in oligodendrocytes that encode myelin depend upon the presence astrocytes rather than other axons.
89. The answer is B.
If the phrenic nerve was cut at the origin the only result listed would be B. This is because the phrenic nerve not only motor to its own half of the diaphragm but also is sensory to the central part of the diaphragmatic pleura.
90. The answer is E.
The pulmonary veins (4) carrying oxygenated blood from the lungs, enter the left, not the right, atrium. The other vessels listed enter the right atrium. In addition to the tributaries of the coronary sinus, there are several small anterior cardiac veins that arise on the surface of the right ventricles and pass across the coronary sulcus to penetrate directly the anterior wall of the right atrium.
91. The answer is E.
Neither of the muscles, gluteus medius or gluteus minimus, is a gluteus minimus may act in the movement. The gluteum minimus also has been shown by electromyography to be active in medial rotation of the thigh while the gluteus medium apparently is active only in lateral rotation and extension of the thigh. These muscles are similar in all the other items listed.
92. The answer is E.
Transverse foramine are characteristic of cervical vertebra. These foramina are formed by a partial fusion of the transverse and costal processes of the cervical vertebrae. Except for the seventh cervical vertebra, the transverse foramina contain the vertebral artery as it passes toward the foramen magnum.
93. The answer is D.
Aspirated objects usually drop into the right main bronchus because it is more vertical than the left main bronchus and thus more nearly in line with the trachea. Smaller objects tend to lodge in the right lower lobar bronchus, which more nearly continuous the direction of the right main bronchus.
94. The answer is A.
Visual defects are usually described in terms of visual field deficiencies (i.e., what a person cannot see). Because the retinal image is reversed and inverted by the ocular optics, the right halves of the visual field are projected on the left halves of the retinas. The nerve fibers from the nasal retinas decussate at the optic chiasm, whereas the temporal fibers remain on the same side. Thus, a lesion within the left optic tract (by definition between the chiasm and the lateral geniculate body) would affect fibers transmitting from the left halves of the retinas
A useful mnemonic, once the retina is activated, is Lower retinal quadrants project the Lateral portion of the lateral geniculate nucleus and after synapse there, project to the Lingual gyrus or Lower lip of the calcarine fissue.
95. The answer is D.
A lesion of the otic ganglion would affect the post-ganglionic secretory fibers of the glossopharyngeal nerve to the parotid gland.
96. The answer is A.
During the latter part of prophase, the chromosomes thicken and become more distinct. Each is double and consists of two strands called chromatids.
97. The answer is A.
The glossopharyngeal nerve supplies general sensation and taste from the posterior one-third of the tongue.
98. The answer is A.
The bile that is produced by the hepatic cells of the liver is first secreted into the bile canaliculi. The canaliculi coalesce to eventually form the right and left hepatic ducts as they leave the corresponding lobes of the liver. The two hepatic ducts unite to form the common hepatic duct, which joins the cystic duct to form the common bile duct. The common bile duct empties into the second part of the duodenum.
99. The answer is B.
The terminal bronchiole is lined by simple columnar or cuboidal cells, ciliated or non-ciliated. Elastic tissue and smooth muscle are present, while cartilage and glands are lacking.
100. The answer is E.
The palperbral portion of the orbicularis oculi muscle (innervated by the facial nerve) produces the blink. The buccal branch of the facial nerve innervates muscles of facial expression (including the buccinators muscle) between the eye and the mouth, while the buccal branch of the trigeminal nerve is sensory. The levator palpebrae superioris muscle, which elevates the upper eyelid, is innervated by the oculomotor nerve, while the involuntary superior tarsal muscle is supplied by sympathetic nerves.
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