Nervous tissue II

Question 1

Gray matter consists of:

Answer 1

Nerve cell bodies and neuroglia

Question 2

White matter consists of:

Answer 2

Myelinated nerve cell axons with some unmyelinated axons and neuroglia

Question 3

What are ganglia?

Answer 3

Collections of nerve cell bodies in the PNS

Question 4

Thoracolumbar outflow corresponds to what spinal levels?

Answer 4

T1 - L2

Question 5

Craniosacral outflow corresponds to what spinal levels?

Answer 5

Cranial nerves + S2 - S4

Question 6

What does the enteric division of the nervous system control?

Answer 6

Peristalsis, gland secretions, blood flow through GI tract

Question 7

What are the classifications of synapses (based on morphology)?

Answer 7

1. Axodendritic
2. Axosomatic
3. Axoaxonic

Question 8

Where are electrical synapses located in humans?

Answer 8

1. Brain stem
2. Retina
3. Cerebral cortex

Question 9

Electrical synapses have what kind of intercellular communication?

Answer 9

Gap junction

Question 10

What are the components of a chemical synapse?

Answer 10

1. Presynaptic element
2. Synaptic cleft
3. Postsynaptic membrane

Question 11

What is kiss-and-run fusion?

Answer 11

When a synaptic vesicle only partially unloads contents

Question 12

What is collapse fusion?

Answer 12

When synaptic vesicle unloads entire contents and fuses to membrane, to be recycled later when membrane gets too large

Question 13

What is choroid plexus located?

Answer 13

Ventricles of brain

Question 14

What are the components of choroid plexus?

Answer 14

1. Folds of pia mater

2. Ependymal cells - simple cuboidal epithelium held together by zonulae occludentes

Question 15

Does the brain have lymphatics?

Answer 15

No

Question 16

Where is CSF reabsorbed?

Answer 16

Arachnoid villi in superior sagittal sinus

Question 17

What is Wallerian degeneration?

Answer 17

Segment of PNS axon distal to injury degenerates (anterograde)

Question 18

What is involved in anterograde changes in PNS nerve injury?

Answer 18

1. Segment distal to injury degenerates (Wallerian degeneration)
2. Phagocytic cells derived from Schwann cells and blood-derived monocytes clean up debris
3. Schwann cells proliferate and along with their external lamina form tubules

Question 19

What is involved in retrograde changes in PNS nerve injury?

Answer 19

1. Proximal to site of injury
2. Cell body swells
3. Chromatolysis - Nissl bodies move to periphery
4. Nucleus moves to periphery
5. Axon grows sprouts and Schwann cells guide them toward target cell
6. Essential cells: macrophages, fibroblasts, basal lamina, Schwann cells