Structure of Nerve Tissue - X

Question 1

Internerouns

Answer 1

Interconnect other neurons, 99.9% of all neurons

Question 2

GVE - information pathway

**

Answer 2

Ventral root of spinal cord, through ventral root out to smooth and cardiac muscle, glands, etc
Two neuron chain

Question 3

GSA - movement of information, how

**

Answer 3

Bring in information from the periphery/body to Spinal Cord.
Cell bodies located in Dorsal Root Ganglion
Information flows through the dorsal root into the dorsal horn of the spinal cord

Question 4

Multipolar - def, e.g.

**

Answer 4

most common
1 axon, 2+ dendrites
motor neurons and interneurons

Question 5

Cell Body - characteristics

Answer 5

large pale staining nucleus
dispersed chromatin
nucleoli
Lots of RER and Nissl bodies (free ribosomes)
numerous mitochondria

Question 6

Unipolar/ psuedounipolar - def, e.g.

Answer 6

1 long axon divides close to cell body into 2 long axial branches
typically prokaryotic
eukaryotic evolution - DRG cells

Question 7

Axon Hillock - def, significance

Answer 7

initial segment of axon w/o Nissl bodies or Golgi

sight of nerve impulse generation - very excitable

Question 8

Bipolar - def, e.g.

**

Answer 8

1 axon, 1 dendrite

associated with receptors for special senses

Question 9

Retrograde

Answer 9

towards cell body
Mediated by Dynein
viruses could be taken up nerve terminal and transferred int CNS
Rate : FAST

Question 10

Anterograde - axonal transport

Answer 10

away from cell body
mediated by Kinesin
two rates : Slow (same as peripheral regeneration)
Fast

Question 11

Neurofilaments - fxn

Answer 11

support

role in neuronal development and regeneration

Question 12

Microfilaments - def, fxn

Answer 12

actin
Anchor
transfer molecules to/from cell membrane
Cause movement of growing axonal tips during development and regeneration

Question 13

Microtubles

**

Answer 13

cylindrical assemblies of tubuli, with axonal transport proteins

Question 14

Presynatic terminal - a..k.a

**

Answer 14

buton

Question 15

Synapses - catergories

**

Answer 15

axo-dendritic (majority))
axosomatic
axoaxonic
dendrodentritic

Question 16

Neuromuscluar junction

**

Answer 16

specialized synapses on skeletal muscle
ACH as nt
junctional folds on muscle fiber membrane

Question 17

Neuroglial cells - fxn, types

**

Answer 17

support and myelination in PNS

Peripheral = Schwann and Satellite cells

Question 18

Schwann Cells - fxn

**

Answer 18

Myelinate peripheral axons
Myelin sheath - concentric rings of Schwann around axon
also surrounds/nurtures unmyelinated axons
thicker myelin = faster conduction

Question 19

DRG

Answer 19

contains cell bodies of pseudounipolar sensory neurons
cell bodies surrounded by satellite cells
NO synapses occur here

Question 20

Schidmt-Laternams clefts - def., fxn

Answer 20

islands of Schwann cytoplasm bwtn lamellae of myelin
= characteristic fishbone appearance on LM
fxn - Intracelluar communication

Question 21

Autonomic Ganglia - characterstics

Answer 21

Multipolar

Synapses OCCUR

Question 22

Sateliite Cells - def, fxn

Answer 22

glial cells that surround peripheral ganglia
Maintain controlled local enviroment
Provide electrical insulation
Path for metabolic exchange

Question 23

CT coverings on nerves

Answer 23

Epineurium
Perineurium
Endoneurium

Question 24

Epineurium

Answer 24

Surround entire nerve

Question 25

Node of Raniver

**

Answer 25

btwn two adjacent Schwann cells (no myelin)
intenodes - have myelin sheath
Nodes have high [Na+] resulting in fast impulse propagationsaltatry transmission ‘jumping’

Question 26

Perineurium

Answer 26

Surround fascicle ( bundle of nerve fibers)

Question 27

Permeability barrier - a.k.a , fxn

Answer 27

blood-nerve barrier btwn perinuerial fibroblasts surrounding nerve fascile
maintains ionic environment of nerve fibers

Question 28

Permeability barrier - a.k.a , fxn

Answer 28

blood-nerve barrier btwn perinuerial fibroblasts surrounding nerve fasicle
maintains ionic environment of nerve fibers

Question 29

Kinesthesia

Answer 29

Detection of movement through space

Question 30

Guillain-Barré syndrome

Answer 30

autoimmune condition - destroys Schwann cells by T cell response against peripheral myelin.
Loss of cutaneous sensation.
Symmetrical ascending weakness.
Pt can survive and recover

Question 31

Nerve Injury Classification - +action

XX

Answer 31

mild compression - demyelination
nerve crush - axons disconnected
complete transection - whole nerve

Question 32

Endoneurium

Answer 32

surround individual axons

Question 33

Nerve Regenration

**

Answer 33

Rate slow - into distal stump
If damaged, some axons grow endoneurial tubes, reestablishes contact with muscle
If growths disorganized, can lead to painful traumatic neuroma at site of injury

Question 34

anterograde Wallerian Denegeration

**

Answer 34

Distal to injury/cut

• axon swells, disintegrates, removed by macrophages
• Schwann cell dedifferetiate, breaking down myelin sheath and blood-nerve barrier
• Schwann cells secrete growth factors, divide and line up as guidance for new axon sprouts

Question 35

Retrograde Chromatolysis

**

Answer 35

Proximal in cell bodies of origin

• Cell body swells
• Nucelus Shifts to periphery
• Nissl substance (RER) breaks down

Question 36

GVA

Answer 36

wall of internal organs, glands and blood vessel to spinal cord

Question 37

GSE

Answer 37

CNS to voluntary skeletal muscle

cell bodies in ventral horn, exit through ventral roots