Chapter 12 Flashcards Preview

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Flashcards in Chapter 12 Deck (21):
1

Neuroglia of CNS

oligodendrocytes,
ependymal cells,
Microgila
Astrocytes
Neuroglia
Astrocytes

2

Neuroglia of the PNS

Schwann Cell
Satellite cell

3

Oligodendrocytes

Form myelin sheath in brain and spinal cord.

4

Ependymal cells

Lines the brain and spinal cord, secretes and circulates CSF

5

Microgila

Phagoctize that destroy microorganisms, foreign matter and dead nervous tissue

6

Astrocytes

1. Cover the brain surface and non synaptic regions of neurons
2. From supportive framework in CNS
3. Induce formation of blood brain barrier
4. Nourish neurons
5. Produce growth factors that stimulate neurons
6. Communicate electrically with neurons and may influence synaptic signaling.
7. Remove K+ and some neurotransmitters fro ECF of the brain and spinal cord
8. Help to regulate composition of ECF from scar tissue to replace damaged nervous tissue.

7

Neuroglia of PNS

1. Schwann Cells
2. Satellite Cells

8

Schwann Cells

Form neurilemma around all PNS nerve fiber and myelin around most of them; aid in generation of damaged nerve fibers.

9

Satellite cells

Surrounding somas of the neuron in the ganglia; provide electrical insulation and regulates chemical environment of neurons

10

Local Potential

Produced by gated channels on the dendrites and soma

11

Action Potential

Produced by voltage-gated channels on the trigger zone and axon.

12

Action Potential

Always begins with depolarization

13

Action Potential

All or non; either does not occur at all or exhibits the same peak voltage regardless of stimulus or strength.

14

Local Potential

May be a positive (depolarizing) or negative (hyperpolerizing) voltage charge Graded proportional to strength.

15

Action Potential

Irreversible, goes to completion once it begins

16

Local Potential

Reversible; returns to RMP if stimulation ceases before threshold is reached

17

Local Potential

Has effects for only a short distance from point of origin.

18

Local Potential

Decremental signal grows weaker with distance

19

Action Potential

Self-propagating; has effects a great distance from point of origin

20

Action Potential

Nondecremental' signal maintains same strength regardless of its distance

21

Acetylcholine ACh

Neuromuscular junctions, most synapses of autonomic nervous system, retina, and many parts of the brain, excites skeletal muscle, inhibits cardiac muscles, and has excitatory or inhibitory effects on smooth muscle and glands depending on location