chapter 12 Flashcards
(25 cards)
efferent vs afferent
efferent (motor)- FROM CNS to organs and muscles. DESCENDING
afferent (sensory)- TO CNS from organs/muscles. ASCENDING
gray matter
cortex, neuron cell bodies
white matter
myelin, collection of axons
tracts
collection of neuron cell processes
what is special about neurons?
amniotic- does not go through mitosis
functions of neurons
motor, sensory, integrate
types of neuron
multipolar- one axon, many dendrites (motor)
bipolar- one axon, one dendtrite
unipolar- start as bipolar then axon and dendrite fuse into one. one process extending. (dorsal root, spinal cord)
what are the supporting cells of neurons and general function
neuroglial cells.
provide support and protection. guide neurons and cells to proper locations in neural development.
astrocytes
BLOOD BRAIN BARRIER
control K+ levels
metabolism of NTs
microglia
derived from monocytes, phagocytize dead tissue/neurons, secrete CSF, ependymal, immune defense
what cells make myelin
oligodendrocyte (in CNS neurons)- wraps SEVERAL AXONS
schwann cells (in PNS neurons)- wraps ONE axon, produces neurilemma (thin sheath, nucleated cytoplasmic layer
what is myelin
phospholipid covering of axon, speeds impulses, rodes of ranvier vs internodes, insulation, conserve ATP
what is multiple sclerosis
when myelin and oligodendrocytes degenerate CNS. blindess, speech deficits, tremors, numbness symptoms
types of conduction and function
saltatory- nodes of ranvier and internodes, Na+ gates channels at internodes, AP travels quickly because insulated
passive- non-myelinated condution, slower, Na+ gates on entire axon
synaptic types
axodendritic- presynaptic terminal makes a synaptic connection with the dendrites of a postsynaptic neuron
axosomatic- presynaptic terminal makes a synaptic connection with the soma of the postsynaptic neuron
axoaxonic- presynaptic terminal makes a synaptic connection with the axon of a postsynaptic neuron. less common
neuronal integration types and what are they
temporal summation- PREsynaptic neurons transmit impulses in rapid fire order
spatial summation- POSTsynatic neuron stimulated by large number of terminals at the same time to help reach threshold
chemical NTs
Ach
biogenic amines
amino acids
peptides
ATP, NO and CO
Ach
degraded by Ache, released by skeletal and some in ANS
biogenic amines
DA, NE, Epinephrine, ST, and histamine
amino acids
GABA(gamma aminobutyric acid)/glycine , aspartate, glutamate
*GABA found only in CNS
*all play roles in metabolism, synthesis and protection across the body
peptides
Substance P- mediator of pain signals
natural opiates, reduce pain perception, bind to homogenous opioid/morphine receptors
novel gases
NO- nitric oxide involved in learning and memory
CO
divergent vs convergent
divergent- input from one nerve fiber branches and synapses with several postsynaptic cells (motor)
convergent- input from multiple nerve fibers to one post synaptic cell (eyes and ears)
excitatory vs inhibitory
Excitatory nt causes depolarization (EPSP)
Inhibitory nt causes hyperpolarization (IPSP)
