PHYSIOLOGY – NERVOUS SYSTEM



PHYSIOLOGY – NERVOUS SYSTEM

1. Which of the following is an example of monosynaptic reflex?

A. Stretch reflex

B. Withdrawal reflex

C. Abdominal reflex

D. Baroreceptor reflex

E. All of the above

2. Which of the following statements regarding muscle spindle is FALSE?

A. It contains nuclear bag & nuclear chain fibers, which are responsible for dynamic & static responses respectively.

B. It is important as a feedback sensor to give information about muscle length

C. It has no contractile elements at all

D. Increased Aγ motor efferent discharge to muscle spindle will lead to increased muscle spindle sensitivity to stretch.

E. Muscle spindle afferent does not fire if the muscle is actively contracted as extrafusal fiber shortened without intrafusal fiber being shortened.

3. Duration of knee jerk reflex response is in the order of:

A. 10 ms

B. 20 ms

C. 30 ms

D. 40 ms

E. 50 ms

4. Increased muscle spindle sensitivity to stretch secondary to increased Aγ efferent discharge can occur with:

A. Anxiety

B. Hypertonia

C. Skin stimulation on the ipsilateral skin

D. Jendrassiks maneuver

All of the above

5. Which of the following statement regarding withdrawal reflex is INCORRECT?

A. It is characterized by flexion of the ipsilateral limb & extension of the contralateral limb when strong noxious stimuli are applied to the skin.

B. Flexing pattern is constant despite the site of stimuli varying in the limb.

C. Withdrawal reflex is prepotent & excludes other reflex activity from taking place.

D. Increased strength of stimuli will increase the number of motor units being recruited & increase the duration of response.

E. Supramaximal stimulation of sensory nerve of a limb never produces as strong a contraction in flexural muscle as elicited by direct electrical stimulation of the muscle itself.

6. Which of the following statements regarding sensory nervous system is INCORRECT?

A. 1o sensory nerve fibers for fine touch & proprioception travels up the ipsilateral dorsal column of spinal cord to reach the medulla

B. 1o sensory nerve fibers for temperature & pain travel up the ipsilateral antero-lateral column of spinal cord to reach the thalamus.

C. Fibers in the dorsal column do not decussate in spinal cord

D. Antero-lateral column also give sensory input to the reticular formation

E. Impulses from sensory nuclei in the substantia gelatinosa are modified by the impulses from descending tracts from the brain & collateral fibers.

7. Which of the following statement regarding sensory fiber arrangement in the spinal cord is CORRECT?

A. In the ventral spino-thalamic tract, cervical sensory fibers are arranged closer to the midline than the sacral fibers

B. In the dorsal column, sacral sensory fibers are arranged closer to the midline than the cervical fibers

C. In the lateral spino-thalamic tract, cervical sensory fibers are arranged closer to the midline than the sacral fibers

D. All of the above

E. None of the above

8. Cortical representation of somatic sensation lies in:

A. Central fissure

B. Pre-central gyrus

C. Post-central gyrus

D. Posterior parietal cortex

E. None of the above

9. Which of the following statement regarding sensory cortex is TRUE?

A. Cells for various sensory modality for a given body part is arranged in columns in the 1o sensory cortex.

B. 2o sensory cortex is found in the sylvian fissure

C. 1o sensory cortex is important for sensory processing regarding position sense & discrimination of size & shape of the objects.

D. 2o sensory cortex is important for learning based on tactile discrimination

All of the above

10. Which type of sensation is most affected in the lesions in sensory cortex?

A. Position & fine touch

B. Temperature differentiation

C. Pain

D. Gross touch

E. All are equally affected

11. Which of the following regarding touch sensation is INCORRECT?

A. Touch sensation in the spino-thalamic tract is more concerned with gross tactile localization.

B. Touch sensation in dorsal column is more concerned with localization, spatial & temporal pattern of touch.

C. Touch sensation is transmitted by C fibers.

D. All of the above

E. None of the above

12. Which of the following statements regarding temperature receptors is FALSE?

A. There are more cold receptors in the skin than warm receptors.

B. Temperature sensory organs are naked sensory nerve endings responding to temperature changes

C. Temperatures sensory organs senses subcutaneous temperature, not skin surface temperature

D. Cold receptors respond to temperature range 10-38oC & warm receptors respond to temperature range 30-45oC

E. Aδ & C fibers are responsible for transmission of temperature sensation.

13. Adaptation to temperature changes occurs at:

A. 0-20oC

B. 20-40oC

C. 40-45oC

D. 45+oC

All of the above

14. Which of the following statements regarding pain sensation transmission is FALSE?

A. Fast or 1st pain is transmitted by Aδ fiber.

B. Slow or 2nd pain is transmitted by C fiber.

C. Pain impulses are modified at the dorsal horn by interneurons & collateral touch fibers.

D. Principal neurotransmitter of pain is histamine

E. Pain perception alone do not require a functional cerebral cortex.

15. Which of the following statements is TRUE?

A. Visceral pain tends to be poorly localized & is often referred to distal sites.

B. Visceral pain can initiate reflex contraction of nearby skeletal muscle

C. Ischemic muscle tends to be persistently painful until reperfusion occurs, due to accumulation of metabolic products such as potassium.

D. Visceral afferents travel along the same pathway as the somatic sensory afferents in the spino-thalamic tract.

E. All of the above.

16.Which of the following statements regarding referred pain is INCORRECT?

A. Superficial somatic pain is sometimes referred.

B. Referred pain usually occurs to a structure from the same dermatomal distribution.

C. Referred pain could be due to convergence of peripheral nerve fiber onto spino-thalamic tract, leading to misinterpretation of the site of pain by the brain.

D. Maxillary sinus pain is usually referred to the teeth.

E. All of the above

17. Opiods act on the following site to produce analgesia:

A. Opiod receptors on afferent nerve fibers at the site of injury.

B. Presynaptic opiod receptors at the dorsal horn to inhibit release of substance P

C. Rostral sites in brain-stem

D. All of the above

E. None of the above

18. Which of the following statements regarding aqueous humor is FALSE?

A. Aqueous humor is produced by ciliary body by active transport

B. Aqueous humor is reabsorbed through the trabecular meshwork into the canal of Schlemn.

C. Canal of Schlemn is found at the anterior chamber angle.

D. Acute angle closure glaucoma is due to the obstruction of anterior chamber angle.

E. Open angle glaucoma is due to reduced permeability of the trabecular meshwork.

19. Which of the followings statements regarding visual reception is INCORRECT?

A. Rods & cones are hidden beneath an array of neurons in the retina.

B. Impulses from rods & cones converge onto a network of neurons & ultimately to the optic nerve.

C. Pigment epithelium absorbs light rays to prevent reflection.

D. Optic disk is situated at the posterior pole of the globe.

E. There are no rods or cones over the optic disk.

20. Which of the following statements about the retina is FALSE?

A. Macula lutea is the point of greatest visual acuity.

B. Retinal blood vessels supply the rods & cones in retina.

C. There are no blood vessels in the macula lutea

D. There are no rods in the macula lutea

E. All of the above

21. Which of the following statements regarding visual pathways is INCORRECT?

A. Objects in the temporal visual field is sensed by the nasal hemiretina

B. Interruption of optic nerve leads to blindness in the ipsilateral eye only

C. Fibers from temporal hemiretina decussate at the optic chiasm

D. Lateral geniculate body receives fibers from the ipsilateral temporal hemiretina & contralateral nasal hemiretina.

22. Which of the following statements regarding visual receptors is FALSE?

A. Outer segment is the photosensitive part of rods & cones that initiates the action potential in the visual pathway.

B. Inner segment is important for the metabolic activity of rods & cones.

C. Rods predominates in the retina (except in the fovea).

D. Cones in the fovea converge onto bipolar nuclei.

E. Cones are more important for acuity & color vision.

23. Which of the following retinal neurons generate “all or none” action potentials?

A. Ganglion cell

B. Bipolar cell

C. Horizontal cell

D. Amacrine cell

E. Rods & cones.

24. Which of the following statement regarding cone & rods is FALSE?

A. Cone receptor potential has sharp onset & offset

B. Rod receptor potential has sharp onset & slow offset

C. Cone responds to a stimulus at a level of illumination below that of rods

D. Both cones & rods generate hyperpolarizing potential when stimulated

E. Sodium channels in the outer segment of rods & cones are closed when strike by light.

25. Which of the following statements regarding lateral geniculate body is TRUE?

A. Each lamina of the lateral geniculate body has a precise mapping of the ipsilateral temporal hemiretina & contralateral nasal hemiretina

B. Lateral geniculate body also receives input from the visual cortex & other brain regions.

C. Magnocellular pathway carries signals for detection of movement & depth to the visual cortex

D. Parvocellular pathway carries signals for texture, shape & fine details to the visual cortex.

E. All of the above

26. Which of the following statements are TRUE?

A. Visual cortex is arranged in 6 layers, each responsible for processing different type of visual information.

B. Parietal cortex, temporal cortex & cingulate gyrus also have 2o visual processing function

C. Reduced visual threshold of cones is responsible for the initial rapid reduction in visual threshold in dark adaptation

D. Time required for dark adaptation is determined by the time required to building rhodospin stores.

E. All of the above

27. Which of the following statements regarding vision is FALSE?

A. Visual acuity is a measurement of visual threshold.

B. Binocular vision relies on the fusion of images from the central visual field of both eyes at the cortical level.

C. Depth can be perceived by monocular vision alone.

D. Bilateral occipital cortical destruction results in subjective blindness but the subject still has residual responses to visual stimuli.

E. Lesions in the lateral geniculate nuclei result in contralateral heteronymous hemianopia with normal pupillary reflex.

28. Normal pupillary reflex can be seen in lesions at:

A. Optic nerve

B. Optic chiasm

C. Optic tract

D. Occipital cortex

E. All of the above

29. Which of the following statements regarding superior colliculi is TRUE?

A. It is an integration center for various visual, auditory & sensory information.

B. It contains motor map which projects to the brainstem to control eye movements.

C. It controls reflex movements of head & neck.

D. It is one of the sites of highest blood flow in the brain.

E. All of the above.

30. Which of the following statement regarding reticular activating system is FALSE?

A. RAS is important for regulation of alertness & consciousness.

B. RAS is found in the anterior pontine region

C. RAS is the site of integration of various polysynaptic reflexes

D. RAS is responsible for regulation of heart rate, blood pressure & respiratory pattern.

E. RAS projects to cortex & thalamic nuclei.

31. Thalamus contain relay nuclei for:

A. Auditory information

B. Visual information

C. Somatosensory information

D. Postural & balance regulation

E. All of the above

32. EEG patterns can be affected by the following EXCEPT:

A. Changes in PaCO2

Changes in temperature

B. Changes in PaO2

C. Glucocorticoid hormone

D. Changes in blood glucose levels

33. Which of the following sleep disorder is associated with REM sleep?

A. Nocturnal enuresis

B. Narcolepsy

C. Night tremors

D. Sleep walking

E. None of the above

34. Which of the following comments regarding lateral corticospinal tract is FALSE?

A. It contains 80% fiber of the corticospinal pathway.

B. It decussates at the level of medullary pyramids.

C. It innervates lateral nuclei in the anterior horn.

D. It controls axial muscle mainly & so is important for posture regulation

E. None of the above

35. Regarding corticospinal (corticobulbar) tract:

A. 30% of corticospinal (corticobulbar) tract is contributed by motor cortex.

B. 30% of corticospinal (corticobulbar) tract is contributed by premotor cortex.

C. 40% of corticospinal (corticobulbar) tract is contributed by somatosensory cortex.

D. All of the above

E. None of the above

36. Which of the following statement regarding the motor homoculus is FALSE?

A. Face is represented bilaterally on the motor cortex.

B. It is located at the post-central gyrus

C. Body parts that perform finely skilled movements have larger representation on the motor cortex.

D. The limbs are represented on the contralateral cortex

E. All of the above

37. Which of the following statements regarding lesions in the motor control pathways is INCORRECT?

A. In a right-handed subject, left motor cortical lesion lead to both left & right hand motor dysfunction.

B. In a right-handed subject, right motor cortical lesion leads to left hand motor dysfunction.

C. In small focal ischemic lesions in the motor cortex, adjacent undamaged areas may learn to take over the responsibility of the damaged areas, thus restoring motor function

D. Babinski sign is a localizing sing to anterior corticospinal tract lesion

E. All of the above

38. Which of the following pairing of cortical area & its function is INCORRECT?

A. 1o motor cortex – control of basic motor movement

B. Premotor cortex – control of distal motor function

C. Supplementary motor cortex – planning of complex motor activity

D. Posterior parietal cortex – planning & integration of sensory & motor function including learned sequences of movements

E. None of the above.

39. Duration of spinal shock in human lasts a minimum of :

A. 2 days

B. 1 week

C. 2 weeks

D. 1 month

E. 2 months

40. Which of the following statement regarding spinal shock is INCORRECT?

A. It is characterized by hyperactive reflex immediately after spinal cord transection.

B. The resting membrane potential during spinal shock is 2-6mV higher than normal.

C. 1st response regained after spinal shock is slight contraction of leg flexion & adductor in response to pain.

D. It may be prolonged with infection & malnutrition.

E. Administration of high dose steroid post transection can minimize loss of function & foster recovery.

41. Complication of spinal cord transection includes:

A. Decubitus ulcer

B. Catabolic state with negative nitrogen balance

C. Hypercalcemia & renal calculi

D. Urinary tract infection

E. All of the above

42. Chronic spinal patient does not have:

A. Hyperactive stretch reflex

B. Flaccid hypotonic bladder

C. Widely swing blood pressure due to loss of baroreceptor reflex

D. Loss of vasomotor control resulting in sweating & blanching of skin.

E. Mass reflex to minor noxious stimuli to skin

43. Which of the following statements regarding decerebration is FALSE?

A. Initial period is marked by spinal shock.

B. Decerebrated animal is able to stand.

C. Spasticity is due to increased excitability of α motor neuron & γ motor neuron.

D. Pattern of decerebration rigidity varies with position.

E. Increased rigidity & extension of ipsilateral limb when head is turned to 1 side.

44. Transection of neural axis at the superior border of midbrain leads to:

A. Marked extensor rigidity in the supine position only

B. Righting reflexes is interact

C. Rigidity is dynamic as the midbrain animal can walk

D. All of the above

E. None of the above

45. Midbrain responses include the following EXCEPT:

A. Vestibulo-ocular reflex (righting reflex)

B. Pupillary reaction

C. Mass reflex

D. Vestibular placing reaction

E. Post-rotatory nystagmus

46. Decortication is marked by:

A. Intact temperature & visceral homeostatic mechanisms

B. Intact learning mechanisms

C. Extensor response to pain

D. Intact placing reaction

E. Intact hopping reaction

47. Striatum sends stimulatory output to:

A. Internal segment of globus pallidus

B. External segment of globus pallidus

C. Substantia nigra

D. Subthalamic nuclei

E. None of the above

48. Chief inhibitory neurotransmitter in the basal ganglia is:

A. Glutamate

B. GABA

C. Dopamine

D. Acetylcholine

E. Noradrenaline

49. Which of the following pairing of parts of cerebellum & its function is CORRECT?

A. Spinocerebellum – motor execution

B. Vestibulocerebellum – balance & eye movement

C. Cerebrocerebellum – motor planning

D. All of the above

E. None of the above

50. Cerebellum receives input from the following sites EXCEPT:

A. Labyrinth & vestibular nuclei

B. Somatosensory pathways

C. Visual impulses from tectum

D. Motor cortex

E. All of the above

51. Destruction of cerebellum leads to the following EXCEPT:

A. Ataxia

B. Hypertonia

C. Dysmetria

D. Dysdiadochokinesia

E. Impaired learning of coordination of repetitive tasks

52. Which of the following regarding hair cells is FALSE?

A. More than 90% of afferent neuron of CN8 innervates the inner hair cells.

B. Most of the efferent neuron of CN8 innervates the outer hair cells.

C. Cochlear nerve connects the hair cells to the dorsal & ventral cochlear nuclei in the medulla.

D. Hair cell processes are bathed in perilymph.

E. All of the above

53. Cochlear nuclei projects to the following location EXCEPT:

A. Inferior Colliculi

B. Reticular formation

C. Vestibulocerebellum

D. Superior olives

E. None of the above

54. Which of the following statements regarding semicircular canals is FALSE?

A. Basal end of the semicircular canal is in contact with the afferent neurons

B. Resting membrane potential is about –60mV

C. Hyperpolarization occur if the cilia is pushed in 1 direction & depolarization occurs if it is pushed in the opposite direction

D. Perilymph has high potassium composition

E. All of the above

55. Normal human’s threshold pressure for sound amplitude is:

A. 0-140 dB

B. 40-180 dB

C. 80-220 dB

D. 120-240 dB

E. 160-280 dB

56. Which of the following regarding hearing is TRUE?

A. Ossicle system serves to magnify the sound pressure arriving at the oval window.

B. Tympanic reflex is adequate to protect an individual from excess stimulation caused by strong sound waves

C. In a normal subject, bone conduction is faster than air conduction

D. Amplitudes of waves set up in the perilymph in scala vestibule are constant.

E. Inner hair cells act to improve hearing by influencing vibration patterns of the basilar membrane.

57. Which of the following statements is FALSE?

A. Pitch of tone cannot be perceived unless it lasts for > 0.01 seconds.

B. Each axon in the cochlear nerve discharges to sound of 1 frequency only.

C. Frequency of sound is encoded in the auditory cortex

D. Auditory cortex respond to onset, duration, direction & repetition rate of auditory stimulus

E. Interpretation of sound signals occurs in auditory association cortex & L Broca’s area.

58. Causes of conduction deafness include:

A. Destruction of auditory ossicles

B. Wax or foreign bodies in the external auditory canal

C. Ear drum thickening

D. Abnormal rigidity of stapes attached to the oval window

E. All of the above

59. Nerve deafness can be due to:

A. Hair cell degeneration secondary to aminoglycosides

B. Prolonged noise exposure

C. Medullary vascular damage

D. Cerebropontine angle & CN8 tumor

E. All of the above

60. Which of the following statements regarding vestibular function is FALSE?

A. Macular discharge tonically in absence of movement because of gravity.

B. Impulses from macula & utricle allow reflex adjustment of head movement & posture.

C. Linear acceleration does not stimulate cristae in the semicircular canal

D. Nystagmus is not present in the blind

E. Nystagmus is a reflex that maintains visual fixation on stationary points as the body rotates.

61. Which of the following statements regarding normal body temperature is TRUE?

A. Body temperature is lowest in the evening & highest in the morning.

B. Body temperature in children is on average 0.5oC lower than adult norms.

C. Rectal temperature is the most accurate estimation of core temperature

D. In increased metabolic state such as hyperthyroidism, temperature can increase by 3-4oC.

E. All of the above

62. Mechanism of increased heat production include:

A. Shivering

B. Hunger

C. Increased voluntary activity

D. Increased adrenaline/noradrenaline secretion

E. All of the above

63. Which of the following regarding temperature regulation is FALSE?

A. Transection of neural axis at midbrain level, thermoregulatory mechanisms remain intact.

B. Lesions in the anterior thalamus lead to increase of core temperature up to 43oC.

C. Lesions in the posterior thalamus lead to reduction of core temperature to below that of environmental temperature.

D. Temperature sensory cells in the hypothalamus senses temperature changes in the nasopharynx & inner ear.

E. All of the above

64. Which of the following statement is TRUE?

A. Human can tolerate body temperature of 21-24oC without permanent sequelae.

B. Heat stroke occurs at temperature > 43oC

C. Malignant hyperthermia is due to excess muscle contraction during stress.

D. Rapid rewarming during hypothermia can result in cell damage due to ice crystal formation.

E. All of the above

ANSWERS:

1. A 11. C 21. C 31. E 41. E 51. B

2. C 12. B 22. D 32. C 42. B 52. D

3. B 13. B 23. A 33. B 43. A 53. C

4. E 14. D 24. C 34. D 44. D 54. D

5. B 15. E 25. E 35. D 45. C 55. A

6. B 16. A 26. E 36. B 46. A 56. A

7. D 17. D 27. A 37. D 47. E 57. C

8. C 18. A 28. D 38. B 48. B 58. E

9. E 19. D 29. E 39. C 49. D 59. E

10.A 20. B 30. B 40. A 50. D 60. D

61. C

62. E

63. C

64. E

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