Lec 13 Nervous System 1 - Histology Flashcards
what is the CNS made up of?
brain and spinal cord
what is the PNS made up of?
somatic (voluntary)
autonomic (involuntary)
what are the 3 functional classifications of neurons?
sensory (afferent) - delivers info to CNS
motor (efferent) - delivers info to PNS (muscle)
associative (interneuron) - located between sensory and motor neurons. Modifies responses of other neurons
what are the 3 structural classifications of neurons? where are they found
multipolar - found throughout brain and spinal cord
bipolar - found in retina and eye and inner ear
unipolar - found in ganglia (clusters of neurons), adjacent to spinal cord
what is the most numerous structural classification of neurons?
multipolar
what does the cell body consist of?
- most of the organelles found in cells [nucleus, mitochondria, golgi, etc]
- nissi bodies
- neurofibrils
what are nissi bodies?
clusters of free ribosomes that produce neurotransmitters and RER -> transport of oxygen
what is the myelin sheath produced by?
oligodendrocyte in CNS
Schwann cell in PNS
what is the neurilemma?
the cell wall of oligodendrocytes or schwann cells
what are the nodes of ranvier?
area of axon not covered by myelin [gaps]
where is the microglia found and what does it do?
CNS
phagocyte that ingests dead tissue
where is the astrocyte found and what does it do?
CNS
nourishment of neurons in CNS
forms blood brain barrier
what is the blood brain barrier composed of? What does it do?
- astrocyte, basement membrane, endothelial wall of capillary
- regulates what substances pass from bloodstream into CNS
what are ependymal cells
cells that line the cavities/ventricles of the brain and spinal cord
where are satellite cells found and what do they do
PNS
supply nourishment to neurons in PNS cells
what is the difference between nerve and tract?
nerve - bundles of axons in PNS
tract - bundles of axons in CNS
what does an electrical impulse cause?
change in permeability of membrane
what is the difference between continuous conduction and saltatory conduction?
continuous - impulse travels in continuous flow along axon. C fibers (slow), less myelinated
saltatory - impulse jumps, or travels from one node of ranvier to the other. A fibers (fast), heavy myelin
what are the different types of excitatory neurotransmitters? what do each of them do?
Acetylcholine (ach) - neuromuscular, controls skeletal muscle.
noreepinephrine - controls autonomic
serotonin - plays role ins leep
dopamine - decrease causes schizophrenia
what are the diff types of inhibitory neurotransmitters & what do each of them do?
gamma aminobutyric acid (GABA) - inhibits cerebellum
enkephalins - stops pain
endorphins - cells in natural pain shut down
dopamine - found in autonomic nervous system
