Chapter 13 - Nervous System: Neural Tissue

Front 1

Central nervous system (CNS) makes up:

Back 1

brain and spinal cord

Front 2

Peripheral nervous system (PNS) makes up

Back 2

all nerves that connect CNS to rest of body

Front 3

Afferent division in PNS:

Back 3

sensory
-peripheral nerves that carry sensory info from receptor to CNS (towar CNS)

Front 4

Efferent division in PNS:

Back 4

motor
-to muscles and glands
-exiting/leaving CNS and out to the body

Front 5

Efferent division has two divisons:

Back 5

1) somatic division
2) autonomic division

Front 6

Somatic division:

Back 6

voluntary control over skeletal muscles

Front 7

autonomic division:

Back 7

involuntary control
1)sympathetic "fight or flight"
-response to unusual stimulus
-remember "E" division: exercise, excitement, emergency, and embarrassment

2)parasympathetic: housekeeping activities (conserve energy)
-remember as "D" division: digestion, defecation, and diuresis
-maintain basic body functions

Front 8

General functions of Nervous system:

Back 8

1) sensory
2) motor
3) regulate physiologic processes
4) intellect- memory, problem solving

Front 9

Sensory Function:

Back 9

gathering information
-involves sensory receptors at end of peripheral nerves
-these pick up info inside and outside body
-change=stimuli

Front 10

Integrative function:

Back 10

-info picked up by receptors is converted into nerve impulses
-travel over PNS to CNS-afferent
-when 2 systems are integrated, results in perceptions

-we act either consciously or subconsciously by the motor function

Front 11

Motor Function:

Back 11

-impulses travel from CNS (efferent) over peripheral nerves to "effectors"
-effectors are responsive part and lie outside of the nervous system

-detect change -> make decision -> cause muscles and glands to respond

Front 12

Nervous Tissue:

Back 12

-neuron=single nerve fiber
-made up of neurons (nerve cells)=structural and functional units of nervous system
-also find neuroglial cells (surround and support) = accessory cells;act like CT
-brain and spinal cord

Front 13

General features of Neuron Structure:

Back 13

Excitable - transmit an action potential

Amitotic - do not divide

Front 14

5 parts of the cell body (soma) of the Neural Structure

Back 14

1) perikaryon
2) neurofibrils
3) nissal bodies
4) mononucleate
5) axon hillock

Front 15

The Perikaryon of the cell body:

Back 15

cytoplasm - found other organelles

Front 16

The neurofibrils of the cell body:

Back 16

network of fine threads; provides support

Front 17

The nissal bodies of the cell body:

Back 17

membranous sacs similar to rough ER - find ribosomes attached

Front 18

The mononucleate of the cell body:

Back 18

one nucleus and nucleolus

Front 19

The axon hillock of the cell body:

Back 19

connects axon to soma - where cell body tapers and joins axon

Front 20

Two components of nerve fibers are:

Back 20

1) Dendrites
2) axon

Front 21

Dendrites function in the nerve fibers is:

Back 21

usually many/nerve cell
-short and highly branched
-act as main receptive sites
-where processes from other neurons communicate
-some have dendritic spines - act as contact points

Front 22

Axon function/structure in the nerve fiber is:

Back 22

only 1 per cell
-slender cylindrival process with uniform diameter
-conducts impulses away from soma
-can give off branches called collaterals
-each collateral has extensions that end with a pre-synaptic (communicates with dendritic spines from the next)terminal that contacts receptive surfaces of another cell

Front 23

Axonal transport in the axon has two types

Back 23

1)anterograde
2)retrograde

Front 24

The axonal transport in the axon is:

Back 24

axoplasmis flow = intracellular movement

Front 25

Anterograde is:

Back 25

the movement away from soma; neurotransmitters, organelles, nutrients

Front 26

Retrograde is:

Back 26

movement toward soma; degrades materials to be recycled and extracellular substances

Front 27

Axoplasm in the axon is:

Back 27

the cytoplasm
-few organelles
-cytoskeletal proteins
-form cytoskeleton
-maintain shape
-generate axoplasmic flow

Front 28

axolemma in the axon is:

Back 28

the plasma membrane

Front 29

the telodendria in the axon is:

Back 29

fine branches at end of axon and collateral branches

Front 30

The synaptic (axon) terminal in the axon is:

Back 30

-find synaptic knob with synaptic vesicles (neurotransmitter)

Front 31

Unipolar structural classification of Neurons is:

Back 31

-several small dendrites converge onto one large dendrite
-dendrites and axon are continuous
-usually myelinated

ex: sensory neurons of PNS

Front 32

bipolar structural classification of neurons is:

Back 32

-several small dendrites converge onto one dendrite
-dendrite and axon separated by soma
-unmyelinated

ex: special sensory organs of CNS

Front 33

Multipolar structural classification of neurons is:

Back 33

-many dendrites extend from soma
-axon typically long
-usually myelinated

ex:lower motor neurons

Front 34

anaxonis structural classification of neurons if:

Back 34

-very small
-axons can not be visually distinguished from dendrites

ex:special sense organs of CNS
(especially in eye)

Front 35

Sensory functional classification of Neurons is:

Back 35

(afferent)
-carry impulses from peripheral body parts into brain or spinal cord
-have receptor ends on dendrites or dendrites are associated with receptor cells in sensory organs
-most are unipolar;few bipolar
-usually myelinated

Front 36

Motor functional classification of Neurons is:

Back 36

a) somatic - skeletal muscle
-innervate skeletal muscles
-multipolar and myelinated

b) visceral (autonomic)
-innervates all other effectors
-usually multipolar and myelinated
-everything else except skeletal muscle

Front 37

interneurons functional classification of neurons is:

Back 37

(associated; intercalated; internuncial)

-in CNS;brain and spinal cord
-most abundant
-act to link 2 neurons
-b/w 2 neurons

Front 38

Anatomical organizations of neurons in NS in the PNS:

Back 38

a) soma are located in ganglia
1)sensory neurons
2)autonomic neurons

b)axons located in nerves

Front 39

Anatomical organizations of neurons in NS in the CNS:

Back 39

a)soma located in nuclei

b) axons located in tracts
-2 or more tracts =column

Front 40

The synapse is:

Back 40

the site of communication between:
- neuron and an effector
- 2 neurons; most common; named based on structure

Front 41

axodendrictic -

Back 41

=0-----<=0-----<

dendrites forward

Front 42

axosomatic -

Back 42

=0----<0----<

dendrites on the side

Front 43

axoaxonic -

Back 43

0
-
-
-
-
>
0----------<

Front 44

2 types of synapses:

Back 44

1) chemical
2) electrical

Front 45

Chemical synapses:

Back 45

- most common
- AP in presynaptic cell -> neurotransmitter is released -> AP in post synaptic cell

Front 46

Electrical synapse:

Back 46

rare (only in CNS)
-AP's transmitted across gap junctions

Front 47

four types of neuroglial cells in CNS:

Back 47

1)astrocytes
2)oligodendrocytes
3)microglia
4)ependymal

Front 48

Astrocytes (neuroglial cell) in CNS:

Back 48

-star-shaped cells between neurons and blood vessels

1)structural support (holds parts together)

2)metabolism (glucose;brain food)

3)regulate concentration of ions in interstitial fluid (potassium)

4)respond to injury (in brain)
- responsible for scar tissue)

5)nutrition (oxygen, glucose)

6) guide developing neurons to targets (guide new neurons to targets)

7)help form blood-brain barrier (decide what gets and what stays)

Front 49

Oligodendrocytes (neuroglial cells) in CNS:

Back 49

-look like astrocytes but smaller
-arranged in rows along nerve fibers

1)form myelin in brain and spinal cord

2)sequester debris after injury

Front 50

microglia (neuroglial cells) in CNS:

Back 50

-smallest and least common

1)supports neurons

2)phagocytize basteria and debris

3)see increase numbers when brain and spinal cord is inflamed

Front 51

ependymal (neuroglial cell) in CNS:

Back 51

-columnar.cuboidal epithelium
-see microvilli and cilia on luminal surface
-joined by gap junctions

found:
1)covers ventricles (space in brain) of brain
2)inner lining of central canal in spinal cord

function:
1)help produce CSF (cerebral spinal fluid)
2)form porous layer for diffusion
3)circulate and monitor CSF composition

Front 52

Two types of Neuroglial cell in PNS:

Back 52

1)satellite cells

2)schwann cells

Front 53

Satelite cell (neuroglial cell) in PNS:

Back 53

-associated with soma
-assist with exchange of nutrients and wastes
-help isolate neuron from stimuli other than those provided at synapse

Front 54

Schwann cell (neuroglial cell) in PNS:

Back 54

=neurolemmocytes
-produce myeline in PNS

function:
1)support neurons
2)prevent contact between axons
3)myelinate large axons

-enclose the axons
-one schwann cell myelinates one axon

Front 55

Unmyelinated axons:

Back 55

appear gray

a)PNS axons
-many axons can associate with a single schwann cell

b)CNS axons
-no associated glia (schwann cell)

Front 56

four functions in a Myelinated Axon:

Back 56

1)myelin
2)neurilemma
3)nodes of ranvier
4)myelination process
5)in CNS & PSN

Front 57

Myelin in a Myelinated Axon:

Back 57

=plasma membrane of glial cell that wraps around axon

-membrane made of lipoprotain

Front 58

neurilemma in a Myelinated Axon:

Back 58

=part of schwann cell that contains sytoplasm

-surrounds myelin sheath
-outside where you find cytoplasm,etc...

Front 59

node of ranvier in a Myelinated Axon:

Back 59

=gaps in myelin sheath between adjacent schwann celss

-set up an action potential

Front 60

myelination process in a Myelinated Axon:

Back 60

-begins around week 14 (fetus)
-completed by 2-3 years

Front 61

steps at chemical synapse:

Back 61

a)AP reaches synaptic knob of presynaptic neuron

b)get released of neurotansmitter

c)neurotransmitter crosses cleft and binds to receptors in postsynaptic membrane

d)results in change in permeability of postsynaptic neuron
-degree of excitation may initiate an AP on postsynaptic membrane
-effects of neurotransmitter fades quickly

Front 62

Neuronal pools:

Back 62

-organized groups of neurons in CNS
-receives impulses from afferent nerve fibers (input)
-impulses processed based on characteristics of pool
-resulting impulses carried away on efferent fibers (output)
-an afferent fiber may divide many times as it enter a pool

Front 63

Facilitation:

Back 63

-due to different incoming impulses, one neuron may receive both excitatory and inhibitory stimuli
-outgoing only sent if net effect is excitatory and enough to reach threshold
-it net effect is excitatory but sub-threshold;no impulse sent but nerve is more excitable = facilitated

Front 64

Convergence:

Back 64

-a single nerve in a pool may receive impulses from 2 or more imcoming fibers
-when they lead to same nerve, they are said to converge
-allows a nerve to summate impulses
-allows nervous system to bring information together from a variety of sources

Front 65

Divergence:

Back 65

-when an impulses leaves a pool, it may spread into several output fibers
-allows an impulse to be amplified

Front 66

Serial Processing:

Back 66

-one neuron to another in series

Front 67

Parallel Processing:

Back 67

processing information from several neurons at once

Front 68

Reverberation:

Back 68

positive feedback continues activity of circuit

Front 69

Ganglia:

Back 69

collection of neuron cell bodies in PNS

Front 70

nuclei:

Back 70

collection of nerve cell bodies in CNS

Front 71

center:

Back 71

collection of neuron cell bodies working together in CNS

Front 72

tracts:

Back 72

bundles of axons in CNS

Front 73

nerves:

Back 73

bundles of axons in PNS

Front 74

white matter:

Back 74

myelinated axons

Front 75

gray matter:

Back 75

non-myelinated material