Nervous Tissue--Downing - Sheet1

Question 1

Neural crest and neural tube. Which gives rise to PNS components? CNS components?

Answer 1

Neural crest = PNS, Neural tube = CNS

Question 2

Can neurons go through mitosis?

Answer 2

No

Question 3

Which nerual tissue cells maintain mitotic capability?

Answer 3

Glial cells

Question 4

What are two key characteristics of the neural cell plasma membrane?

Answer 4

semi permeable to ions. can propagate action potential

Question 5

neurofillaments are ______.

Answer 5

intermediate fillaments

Question 6

axons are ______

Answer 6

microtubules

Question 7

the growth cone of axons are _______.

Answer 7

actin

Question 8

Where are lots of mitochondria found in the neuron?

Answer 8

axon terminals

Question 9

Nissl substance or Nissl bodies

Answer 9

rER. extensive due to high levels of protein synth. absent from axon hillock and axon.

Question 10

What special role does the Golgi have in neurons?

Answer 10

produces synaptic vesicles and neurotransmitter secretion

Question 11

Retrograde movement is which direction?

Answer 11

terminal to cell body (dynein)

Question 12

Orthograde movement is which direction?

Answer 12

cell body to terminal (kinesin)

Question 13

axonal transport slow component?

Answer 13

only orthograde driection.

Question 14

axonal transport fast component?

Answer 14

orthograde faster and retrograde slower. transports synaptic vesicles, mito, acetylcholinesterase, etc.

Question 15

Clinical significance of retrograde motion?

Answer 15

toxins (eg. Rabies) can get transported from PMS to CNS! Developmental problems associated too.

Question 16

Orthograde motor?

Answer 16

kinesin (ATPase) moves along microtubles.

Question 17

Retrograde motor?

Answer 17

dynein (ATPase) moves along microtubles.

Question 18

Orthograde movement uses kinesins, which travel from the ____ end to the ____ end of the microtuble.

Answer 18

minus to plus

Question 19

microglia

Answer 19

related to macrophage. function = phagocytosis

Question 20

oligodendrocyte

Answer 20

helps form myelin sheath.

Question 21

astrocyte function

Answer 21

structural support, uptake of extracellular K+ from neural activity

Question 22

oligodendrocyte function

Answer 22

myelinatoin of CNS axons

Question 23

Ependymal cells

Answer 23

function = cilia move CSF, transport of substances from CSF into brain.

Question 24

Endoneurium, Perineurium, Epineurium

Answer 24

epi = upon, peri = around/surrounding, endo = inside/within

Question 25

Nodes of Ranvier

Answer 25

high conc. of Na+ channels, unmyelinated

Question 26

multiple sclerosis

Answer 26

demyleinating disorders–degeneration of oligodendrocytes.

Question 27

Location and characteristics of sensory ganglia

Answer 27

Dorsal root ganglia; sensory ganglia of cranial nerves V, VII, VIII, IX, and X. Nerve cells are pseudounipolar, cell bodies are in ganglia.

Question 28

Sympathetic ganglia

Answer 28

Discrete structures with capsules: superior cervical, celiac, superior mesenteric, etc.

Question 29

Parasympathetic ganglia

Answer 29

Small and encapsulated in head; elsewhere simply isolated clusters of cells: ciliary or otic ganglia in head; submucosal and myenteric plexi of gut

Question 30

Cell bodies of postganglionic neurons

Answer 30

Think PNS! multipolar neurons, eccentric nuclei, sometimes binucleate, axons terminate on effector organs (smooth muscle, cardiac muscle, glands)

Question 31

Acetylcholine

Answer 31

released at termination of preganglionics of both sympathetic and parasympathetic fibers and postganglionic of parasympathetics.

Question 32

Norepinephrine

Answer 32

released at termination of postganglionic sympathetics except for acetylcholine in the sympathetic innervation of sweat glands

Question 33

Wallerian (Orthograde) Degeneration

Answer 33

Axon, axon terminals, myelin disintegrate
Schwann cell sheath and c.t. layers remain in PNS; no CNS counterpart
Phagocytosis of debris (Schwann cells & macrophages)

Question 34

Retrograde degeneration

Answer 34

Degeneration of axon and myelin sheath in direction of cell body
Chromatolysis—movement of rER and overall diminishing

Question 35

Can neural cells regenerate?

Answer 35

Successful only in PNS

Success depends partly on type of injury

Question 36

Why is CNS regeneration is usually abortive?

Answer 36

oligodendrocytes do not form a guiding tube. Scar tissue produced by astrocytes is a significant barrier.

Question 37

What are traumatic neuromas?

Answer 37

heterogenious mass of nerve fibers, Schwann cells. Occurs when regenerating neuron cannot reconnect. Afferent neurons in neruomas send messages centrally, which are often interpreted as pain.