Nervous Tissue CH 11 Flashcards Preview

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Flashcards in Nervous Tissue CH 11 Deck (41):
1

Functions of the nervous system

1.Sensory input (PNS)
2. Integration (CNS)
3.Motor output (PNS)

2

Peripheral Nervous System (PNS)

Not including the CNS (brain and spinal cord)
Consists or spinal and cranial nreves

3

PNS functional subunits

Afferent
Efferent

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Afferent Division

Sensory "carrying towards"
1. Somatic sensory fibers: convey impulses from skin, muscles and joints
2. Visceral sensory fibers: transmit from visceral organs (in ventral body cavity)

5

Efferent Division

Motor "carrying away"
1.Somatic NS: voluntary, controls skeletal muscles
2. Autonomic NS: involuntary, controls heart pumping digestion ect.

6

Neuroglia (or glial cells)

6 cells that make us neurons:

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Neuroglia of the CNS

Astrocytes
Microglial
Ependymal
Oligodendrocytes

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Neuroglia of the PNS

Satellite cells
Schwann Cells

9

Astrocytes

Most abundant & versatile
Making exchanges between capillaries and neurons
Mopping up leaked K+
Recycling released neurotransmitters

10

Microglial Cells

Type of macrophage
Phagocytize microorganisms and neural debres
Janitor

11

Ependymal Cells

Line CNS cavities
Cilia helps circulate CSF

12

Oligodendrocytes

Form myelin sheaths around CNS fibers

13

Satellite cells

unknown function may be similar to astrocytes

14

Schwann Cells

Vital for regeneration of peripheral nerve fibers.
Form myelin sheath
Similar to oligodendrocytes

15

Dentrites

Receptive, input region
Each neuron has many dentrites
Motor neurons, off the cell body
Short, tapering, diffusley branching extentions

16

Axons

Each neuron has one axon
spender process
long axon = nerve fiber
Conducting region

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Axon Hillock

cone shaped initial region of the axon

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Axon Collaterals

Extend from axon at right angles

19

Axon terminals

Secretory region
knoblike distal ends of axon terminal branches

20

Myelin Sheath

White, fatty fibers (protein-lipiod)
Protects, electronically insulates and increases speed on nerve impulse
Only on axons not dendrites.

21

White matter

Myelinated regions of the CNS, primary fiber tracts.

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Grey matter

Unmyrlinated fibers and contains mostly nerve cell bodies.

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Nodes of Ranvier

Gaps in myelin sheath

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Neuron structural classifications

Multipolar
Bipolar
Unipolar

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Multipolar neurons

3 or more processes (1 axon the rest dendrites)
Most common
Major type in CNS

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Bipolar neurons

2 processes
(1 axon 1 dendrite)
retina and olfactory mucosa

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Unipolar neurons

Single short process
emerges from cell body
divides T-like into proximal and distal branches
Found in PNS ganglia

28

Interneurons

Multipolar
lie between sensory and motor
In CNS

29

Action Potential

Nerve impulse, conduction impulse that travels down the axon.

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Voltage

Potential energy generated by separated charge.

31

Current

Flow of electrical charge from one point to another

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Resistance

The hindrance to charge flow provided by substance it passes through

33

Ohm's Law

Current= voltage/resistance

34

2 membrane ion channels

1. Chemically gated
2. Voltage gated

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Chemically gate ion channels

Open when neurotransmitter binds

36

Voltage gated ion channels

Open and close in response to changes in membrane potential.

37

Resting membrane potemtial

The potential difference in a resting neuron

38

Generating resting membrane potential depends on:

1. Differences in K+ and Na+ concentrations in and out of the cell.
2. Differences in permeability of plasma membrane to those ions.

39

Change in membrane potential can produce:

1. Graded potentials:Incoming signals over short distances
2. Action potentials: long dostance signals of axons

40

Depolarization

Decrease in membrane potential

41

Hyperpolarization

Increase in membrane potential