For each question, state whether points from (a) to (e) true or false and explain your answer:
1- A reflex action:
a. Is initiated at a sensory receptor organ.
b. May result in endocrine secretion.
c. Involves transmission across at least two central nervous synapses in series.
d. May be excitatory or inhibitory.
e. Is independent of higher centers in the brain
.
2-In skeletal muscle neuromuscular junctions:
a. The motor end plate is the motor nerve terminal.
b. Spontaneous (miniature) potentials may be recorded in the motor nerve terminal.
c. Motor nerve terminals have vesicles containing acetylcholine.
d. There is a high concentration of acetylcholinesterase.
e. Transmission is facilitated by botulinum toxin.
3-In sensory receptors:
a. Stimulus energy is converted into a local depolarization.
b. The generator potential is graded and self-propagating.
c. A generator potential can be produced by only one form of energy.
d. The frequency of action potentials generated doubles when the strength of the stimulus doubles.
e. Serving touch sensation, constant suprathreshold stimulation causes action potentials to be generated at a constant rate.
4-A somatic lower motor neuron:
a. Innervates fewer fibers in an eye muscle than does one innervating a leg muscle.
b. Conducts impulses at a speed similar to that in an autonomic postganglionic neuron.
c. Is unmyelinated.
d. Conducts impulses which cause relaxation in some skeletal muscles.
e. Synapse with skeletal muscle but not with other neurons.
5-Impulses serving pain sensation in the left foot are relayed:
a. Across synapses in the left posterior root ganglion.
b. By fibers in the left spinothalamic tract.
c. By the same spinal cord tract which serves heat and cold sensation.
d. To the thalamus on the right side.
e. To the cerebral cortex before entering consciousness.
6-An excitatory post-synaptic potential:
a. Is the depolarization of a post-synaptic nerve cell membrane that occurs when a presynaptic neuron is stimulated.
b. Involves reversal of polarity across the post-synaptic nerve cell membrane.
c. May be recorded from a posterior root ganglion cell.
d. Is propagated at the same rate as an action potential.
e. Is caused by the electrical field induced by activity in the pre-synaptic nerve terminals.
7-The cerebellum:
a. Modifies the discharge of spinal motor neurons.
b. Is essential for finely coordinated movements.
c. Has an afferent input from the motor cortex.
d. Has an afferent input from muscle proprioceptors.
e. Has an afferent input from the vestibular system.
8-During deep sleep there is a fall in:
a. Hand skin temperature.
b. Arterial PCO2.
c. Blood growth hormone/cortisol ratio.
d. Metabolic rate.
e. Urine formation.
9-Sympathetic:
a. Ganglionic transmission is mediated by acetylcholine.
b. Neuromuscular transmission at the heart is mediated by adrenaline.
c. Neuromuscular transmission in hand skin arterioles is mediated by acetylcholine.
d. Neuroglandular transmission at eccrine sweat glands is mediated by noradrenaline.
e. Neuromuscular transmission at the iris is mediated by noradrenaline.
10-The electroencephalogram normally shows voltage waves:
a. Whose amplitude is related to intelligence.
b. Of smaller amplitude during deep sleep than during alert wakefulness.
c. Of lower frequency during deep sleep than during alert wakefulness.
d. Of greater amplitude than those of the electrocardiogram.
e. Which are bilaterally symmetrical.
Answer
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الأربعاء مارس 16, 2011 6:05 am
