Nervous Tissue Flashcards
What are the two divisions of the nervous system?
central and peripheral
Two cell types of nervous tissue
neurons and glia cells
what stage are neurons arrested in?
G0
Functions of nervous tissue
-generate and carry out nerve impulses
-respond to stimuli
-communication and integration
-electrical insulation to nerve cells
Multi-polar neuron
most common
-several dendrites
bipolar neuron
single dendrite opposite axon
unipolar neuron
no dendrites on soma, axon only
pseudounipolar
single dendrite and axon fuse
-soma off to one side
What are the 3 categories of supporting cells in nervous tissue?
Neuroglia (CNS), Schwann cells (PNS), and satellite cells (ganglia)
What receive stimuli from other neurons or environment?
Dendrites
What send stimuli to other neurons or effector cells?
axons
Where do axons start?
Axon hillock
Where do axons end?
Terminal bouton
What is the movement of product down an axon?
Axonal transport
What is moved during slow axonal transport and how fast does it move?
cytoskeletal elements
1-5mm/day
What is moved during fast axonal transport and how fast does it move?
membrane bound organelles
400mm/day
What is anterograde transport?
Movement form cell body down axon
-uses kinesin
What is retrograde transport?
Movement from axon to cell body
-uses dynein
What is the reversal of charge across the cell membrane?
Action potential
Depolarization
slight change in membrane potential causes voltage gates sodium channels to open
-Na rushes in
-cell membrane becomes positively charged
Repolarization
Voltage gated potassium channels open
-K rushes out
cell membrane is now negatively charged
refractory/recovery period
time period in which sodium channel can not open again
What is entrainment?
the more a pathway is used, the easier it is to access
Where do neurons meet with muscles?
neuromuscular junction
Space between the neuron and the target
synaptic cleft
Neurotransmitter of sympathetic
norepinephrine
Neurotransmitter of parasympathetic
acetylcholine
What do the vesicles on post-synaptic membrane contain?
enzymes to break down NT to ensure there is no continuous stimulation (tetany)
what surrounds individual neurons?
endoneurium
What surrounds fascicles of neurons?
perineurium
What surrounds nerve fibers?
epineurium
What causes the waviness of neurons staining?
Nodes of Ranvier
Somatic=
voluntary
autonomic=
involuntary
What do Schwann cells do?
Wrap around the axon of nerves
-provide insulation for nerve impulses
-allow for rapid, saltatory contraction
Where does membrane depolarization occur?
Nodes of Ranvier
Where are preganglionic cell bodies of CNS located?
gray matter of brain and spinal cord
Where are post ganglionic cell bodies of CNS located?
In ganglia
What are ganglia?
aggregates of post synaptic neuron cell bodies outside the CNS
what surrounds each cell body?
satellite cells
Where are sympathetic ganglia located?
parallel to vertebral column
-prevertebral: anterior to spine
-paravertebral: in sympathetic trunk
Where are parasympathetic ganglia located?
in or near effector organ
