Overview of CNS And PNS (4)

Question 0

From rostral to caudal, what are the 5 major brain segments?

Answer 0

1. Telencephalon
2. Diencephalon
3. Mesencephalon
4. Metencephalon
5. Myelencephalon

Question 1

Sagittal planes divide the brain how?

Answer 1

Into right and left; is a lateral cross section

Question 2

Which brain segment includes the medulla?

Answer 2

Myelencephalon

Question 3

Which brain segment contains the cerebral hemispheres?

Answer 3

Telencephalon

Question 4

Which brain segment contains the pons and cerebellum?

Answer 4

Metencephalon

Question 5

Which brain segment contains the thalamus and hypothalamus?

Answer 5

Diencephalon

Question 6

Which brain segment contains the midbrain?

Answer 6

Mesencephalon

Question 7

Gray matter has high densities of what?

Answer 7

Neurons ( specifically somas and dendrites, both of which are unmyelinated)

Question 8

White matter has high densities of what?

Answer 8

Axons.

Question 9

In the forebrain is gray or white matter on the outer surface?

Answer 9

Gray matter ( there are nuclei of gray matter deep in the brain as well; nuclei in the brain are the same as ganglia in the periphery, both have cell bodies)

Question 10

In the spinal cord, is gray or white matter on the outer surface?

Answer 10

White matter

Question 11

What are the five functional loves of the brain?

Answer 11

1. Frontal
2. Parietal
3. Occipital
4. Temporal
5. Limbic

Question 12

What is the function of the thalamus?

Answer 12

Relay center for sensory (except olfactory) and motor afferents into the cortex. Also integrates higher order cognitive and emotional information

Question 13

What is the function of the basal ganglia?

Answer 13

Smooths out motor movements of the limbs and axial musculature during body movement

Question 14

What are the three components of the brainstem?

Answer 14

1. Midbrain
2. Pons
3. Medulla (which connects brain to spinal cord)

Question 15

How can there be 8 cervical spinal cord segments but only 7 cervical vertebrae?

Answer 15

The first cervical spinal nerve exits above C1. Most of the rest exit beneath the similarly numbered vertebrae. (Except spinal nerve C8 comes out beneath C7)

Question 16

In the adult at approx. what vertebral level does the spinal cord end?

Answer 16

T12 - L1

Question 17

Why do the lower thoracic, lumbar, and sacral nerves exit the spinal canal several levels below their exit from the spinal cord itself?

Answer 17

The vertebral column grows faster than the spinal cord beginning at about 3 mo gestation, so there is an apparent rostral shift of the spinal cord. (In the infant, the spinal cord ends at approx. L3; compare to T12-L1 in the adult)

Question 18

What does the dorsal root of a spinal nerve conduct?

Answer 18

Afferent peripheral sensory nerve fibers traveling to the cord

Question 19

What do the ventral roots of spinal nerves conduct?

Answer 19

Efferent motor nerves traveling to muscles, organs, etc

Question 20

On what neurons and where in the spinal cord do the neurons originating from the corticospinal tract terminate?

Answer 20

In the lower motor neuron located in the anterior horn

Question 21

Where does the cell body of the most peripheral nerve in the spinothalamic tract reside?

Answer 21

In the dorsal root ganglion.

Question 22

Where does the spinothalamic tract decussate?

Answer 22

In the spinal cord, just after entering. The second neuron, which the pseudounipolar sensory neuron with cell body in dorsal root ganglia first synapses on in the gray matter of the dorsal horn, decussates, then travels rostrally

Question 23

Where does the 2nd neuron in the spinothalamic tract synapse with the third?

Answer 23

In the thalamus (ventral posterior nucleus of the thalamus to be exact). The third neuron then travels to neurons in the sensory cortex of the forebrain to complete the pathway.

Question 24

Which sensory pathway informs the brain of the position of ones body parts in space?

Answer 24

Posterior (Dorsal) column

Question 25

Where are the originating neurons of the posterior (dorsal) column located?

Answer 25

Dorsal root ganglia; are pseudounipolar neurons like those in the spinothalamic tract (makes sense! both are sensory pathways)

Question 26

Where does the posterior (dorsal) column decussate?

Answer 26

In the medulla. It is the 2nd neuron that actually travels to the opposite side. (The 1st neuron travels all the way up to the medulla from the periphery w/o synapsing)

Question 27

Where does the 1st neuron in the posterior (dorsal) column synapse into the second?

Answer 27

In the gracile or cuneate nuclei in the medulla.

Question 28

Where does the second neuron in the posterior (dorsal) column synapse with the third?

Answer 28

In the ventral posterior lateral (VPL) nucleus of the thalamus. This VPL neuron travels up and synapses on neurons in the sensory cortex

Question 29

Where in the spinal cord does the peripheral neuron of the spinothalamic tract synapse with the second neuron?

Answer 29

In the gray matter of the dorsal horn

Question 30

What two brain structures regulate the autonomic nervous system? What does the autonomic NS control (which 3 letter type of fibers are they)?

Answer 30

Thalamus and hypothalamus. Autonomics are GVE; they control smooth and cardiac muscle, and glands

Question 31

Coronal planes divide the brain how?

Answer 31

Into front and back; perpendicular to an axial, or horizontal, cut