CNS & PNS Study Questions

Question 1

What portion of the spinal cord connects with nerves of the upper limbs?

Answer 1

The cervical enlargement connects with the sensory and motor nerves of the upper limbs.

Question 2

What is the difference between a horn and a column in the spinal cord?

Answer 2

A horn is an area of gray matter and a column is an area of white matter.

Question 3

Why does complete severing of the spinal cord at level C2 cause respiratory arrest?

Answer 3

Severing the spinal cord at level C2 causes respiratory arrest because it prevents descending nerve impulses from reaching the phrenic nerve, which stimulates contraction of the diaphragm, the main muscle needed for breathing.

Question 4

What five important nerves arise from the brachial plexus?

Answer 4

The axillary, musculocutaneous, radial, median, and ulnar nerves are five important nerves that arise from the brachial plexus.

Question 5

What initiates a nerve impulse in a sensory neuron?

Answer 5

A sensory receptor produces a generator potential, which triggers a nerve impulse if the generator potential reaches threshold. Reflex integrating centers are in the CNS.

Question 6

Which branch of the nervous system includes all integrating centers for reflexes?

Answer 6

Reflex integrating centers are in the CNS.

Question 7

What is reciprocal inhibition?

Answer 7

Reciprocal inhibition is a type of arrangement of a neural circuit involving simultaneous contraction of one muscle and relaxation of it antagonist.

Question 8

Which is the largest part of the brain?

Answer 8

The cerebrum is the largest part of the brain.

Question 9

What are the three layers of the cranial meninges from superficial to deep?

Answer 9

From superficial to deep the three cranial meninges are the dura mater, arachnoid, and pia mater.

Question 10

Which brain region is anterior to the fourth ventricle? Which is posterior to it?

Answer 10

The brain stem is anterior to the fourth ventricle, and the cerebellum is posterior to it.

Question 11

Where is cerebrospinal fluid reabsorbed?

Answer 11

The cerebrospinal fluid is reabsorbed by the arachnoid villi that project into the dural venous sinuses.

Question 12

What does decussation mean?

Answer 12

Decussation means crossing to the opposite side.

Question 13

What is the functional consequence of decussation of the pyramids?

Answer 13

The functional consequence of decussation of the pyramids is that each side of the cerebrum control muscles on the opposite side of the body.

Question 14

Which tracts carry impulses between gyri of the same hemisphere?

Answer 14

Association tracts connect gyri of the same hemisphere

Question 15

Which tracts carry impulses between gyri in opposite hemispheres?

Answer 15

Commissural tracts connect gyri in opposite hemispheres

Question 16

Which tracts carry impulses from the cerebrum to the thalamus, brain stem, and spinal cord?

Answer 16

Projection tracts connect the cerebrum with the thalamus, brain stem, and spinal cord.

Question 17

Where are the basal ganglia located relative to the thalamus?

Answer 17

The basal ganglia are lateral, superior, and inferior to the thalamus.

Question 18

Where do axons in the olfactory tracts terminate?

Answer 18

Axons in the olfactory tracts terminate in the primary olfactory area in the temporal lobe of the cerebral cortex.

Question 19

Where do the motor axons of the facial nerve originate?

Answer 19

Motor axons of the facial nerve originate in the pons.

Question 20

What important motor functions does the hypoglossal nerve mediate?

Answer 20

Two important motor functions of the hypoglossal nerve are speech and swallowing.

Question 21

How is a muscle spindle activated?

Answer 21

Muscle spindles are activated when the central areas of the intrafusal fivers are stretched.

Question 22

What type of sensory deficits could be produced by damage to the right lateral spinothalamic tract?

Answer 22

Damage to the right lateral spinothalamic tract could result in loss of pain and thermal sensations on the left side of the body.

Question 23

How do the somatosensory and motor representations compare for the hand, and what does this difference imply?

Answer 23

The hand has a larger representation in the motor area than in the somatosensory area, which implies greater precision in the hand’s movement control than fine ability in its sensation.

Question 24

Which tracts carry information from proprioceptors in joints and muscles to the cerebellum?

Answer 24

The anterior and posterior spinocerebellar tracts carry information from proprioceptors in joints and muscles to the cerebellum.

Question 25

Because they contain both sensory and motor axons, spinal nerves are considered to be ____________ nerves.

Answer 25

Mixed

Question 26

The epidural space is located between the wall of the vertebral canal and the pia mater. True/False

Answer 26

False

Question 27

Gray matter of the spinal cord contains somatic motor and sensory nuclei, autonomic motor and sensory nuclei, and functions to receive and integrate both incoming and outgoing information. True / False

Answer 27

True

Question 28

Which of the following is a motor tract? (a) posterior spinocerebellar (b) lateral spinalthalamic (c) anterior spinocerebellar (d) lateral corticospinal (e) posterior column

Answer 28

D

Question 29

The cerebral hemispheres are connected internally by a broad band of white matter know as the ____________________.

Answer 29

Corpus Callosum

Question 30

List the five lobes of the cerebrum.

Answer 30

Frontal, Parietal, Temporal, Occipital, Insula

Question 31

The brain stem consists of the medulla oblongata, pons and diencephalons. True/False

Answer 31

False

Question 32

_____________ is the conscious or subconscious awareness of external or internal stimuli; _____________ is the conscious awareness and interpretation of sensory input.

Answer 32

Sensation and Perception