Neural Histology

Question 1

neurons

Answer 1

nerves cells, quickly send messages from cell to cell

Question 2

nervous system steps

Answer 2

1. receive info about change in body and external environment then transmits message to CNS
2. CNS processes info and determines the response
3. CNS issues commands primarily to muscle and gland cells to carry out response

Question 3

central nervous system

Answer 3

brain and spinal cord, performs most decision making functions

Question 4

peripheral nervous system

Answer 4

rest of system, nerves and ganglia

Question 5

nerve

Answer 5

bundle of nerve fibers wrapped in fibrous connective tissue

Question 6

ganglion

Answer 6

knotlike swelling in a nerve where cell bodies of PNS neurons are concentrated

Question 7

sensory (afferent) division

Answer 7

carries signals from various receptors

Question 8

somatic sensory division

Answer 8

carries signals form receptors in skin muscles, bones and joints

Question 9

visceral sensory division

Answer 9

mainly from viscera of thoracic and abdominal cavities

Question 10

motor (efferent) division

Answer 10

carries signals from CNS mainly to gland and muscle cells that carry out body responses

Question 11

somatic motor division

Answer 11

carries signals to skeletal muscles

Question 12

visceral motor division (ANS)

Answer 12

carries signals to glands, cardiac muscle and smooth muscles

Question 13

sympathetic division

Answer 13

arouses body for action

Question 14

parasympathetic division

Answer 14

calming effect

Question 15

enteric plexus

Answer 15

lies in walls of digestive tract, enables regions of tract to communicate and coordinate their motility and secretion

Question 16

properties of neurons

Answer 16

excitability, conductivity, secretion

Question 17

sensory (afferent neurons)

Answer 17

specialized to detect stimuli like light, heat, pressure and chemicals then transmit info about them to CNS
- begin in most every organ and end in CNS

Question 18

interneuron

Answer 18

lie entirely in CNS, receive signals from many other neurons and carry out integrative function of nervous system
- process, store and retrieve info and make decisions to determine stimuli responses
- ~90% of neurons

Question 19

motor (efferent) neurons

Answer 19

send signals mostly to muscle and gland cells

Question 20

cell body

Answer 20

control center of neuron

Question 21

neurites

Answer 21

extensions reading out to other cells

Question 22

dendrites

Answer 22

most neurites, resemble tree branches
- primary site for receiving signals

Question 23

axon hillock

Answer 23

mound on on side of cell body

Question 24

axoplasm and axolemma

Answer 24

cytoplasm and membrane of axon

Question 25

terminal arborization

Answer 25

extensive complex of fine branches and distal end of axon

Question 26

axon terminal

Answer 26

bulbous form at end of each branch, forms synapses

Question 27

multipolar neurons

Answer 27

one axon and multiple dendrites

Question 28

bipolar neurons

Answer 28

one axon and one dendrite

Question 29

unipolar neurons

Answer 29

one single process leading away from cell body

Question 30

anaxonic transport

Answer 30

multiple dendrites but no axon

Question 31

axonal transport

Answer 31

2 way passage of proteins, organelles, and other materials along an axon

Question 32

anterograde transport

Answer 32

away from cell body down axon

Question 33

retrograde transport

Answer 33

up axon toward cell body

Question 34

fast axonal transport

Answer 34

200-400 mm/day - retrograde or anterograde - moves mitochondria, synaptic vesicles, other organelles, components of axolemma, calcium ion, enzymes and small molecules - informs cell body of conditions at axon terminals

Question 35

slow axonal transport

Answer 35

anterograde, works in stop and go fashion - like local train that stops at every station - 0.2-0.5 mm/day - moves enzymes, parts of cytoskeletal down axon, renews workout axoplasmic parts and supplies new axoplasm for developing/regenerating neurons

Question 36

neuroglia/glial cells

Answer 36

non-neural supportive cells - protect neurons and help them function - bind neurons together and make supportive framework

Question 37

oligodendrocytes

Answer 37

kinda look like octopus, have bulbous body with as many as 15 arms - each arm spirals around an axon creating myelin sheath

Question 38

ependymal cell

Answer 38

resemble cuboidal epithelium lining internal cavities of brain and spinal cord - produce cerebrospinal fluid

Question 39

microglia

Answer 39

small macrophages that develop from white blood cells - wander through CSF probing tissue for debris or other problems

Question 40

astrocytets

Answer 40

most abundent in CNS - cover entire brain surface and most non synaptic regions of neurons in gray matter

Question 41

Schwann cells/neurilemnocytes

Answer 41

envelope axons of PNS - winds repeatedly around axon and produce myelin sheath and assist in axon regeneration

Question 42

satellite cells

Answer 42

surround nerve cell bodies in ganglia of PNS - provide insulation and regulate chemical environment

Question 43

myelin sheath

Answer 43

spiral layers of insulation around an axon - made of protein and unique lipids

Question 44

neurolemma

Answer 44

thicker outermost coil of myelin sheath

Question 45

myelin sheath gap/node of ranvier

Answer 45

gap between segments of sheath

Question 46

internal segments

Answer 46

covered segments from each node to the next - 0.2-1 mm long

Question 47

initial segment

Answer 47

short section of axon between axon hillock and first glial cell (trigger zone)

Question 48

speed of signals

Answer 48

- small unmyelinated: .5-2 m/s - small myelinated: 3-15 m/s - large myelinated: 120 m/s

Question 49

regeneration

Answer 49

can occur if cell body is intact and some neurolemma remains