The Nervous System Flashcards
what is the functions of the nervous system?
control and communication
3 basic functions?
- sensing change, 2. interpreting and remembering change 3. reacting to change
what composes the central nervous system?
brain and spinal cord
what composes peripheral nervous system?
cranial nerves and spinal nerves
functional division of the peripheral nervous system?
somatic, autonomic and enteric
what is somatic nervous system?
sensory neurons from somatic receptors to CNS and Motor neurons form CNS to muscle tissue
what is autonomic nervous system?
sensory from visceral organs to CNS, motor neurons to smooth muscle tissue, cardiac muscle and glands; sympathetic (fight), parasympathetic (stop)
what is enteric nervous system?
network of sensory and motor neurons in wall of GI tract
the cell body of a neuron contains?
nucleun, cytoplasm, nissl body, neurofilament, microtubules, lipofuscin pigment granules
dendrites contain?
nissl body, neurofibrils
axon contain?
mitochondria, micotubules, neurofibrils
axon begins at?
axon hillock
structural classification of neurons?
multipolar, bipolar, unipolar
what is multipolar neuron?
one axon many dendrites
what is bipolar neuron?
one axon, one main dendrite
what is unipolar?
one process, always sensory
what are association neurons?
based on how they look or who described thenm first
what are neuroglia?
supportive, protective, “nerve glue”, smaller than neurons 50%, half the volume in CNS, capable of mitosis
glia in CNS?
astrocytes, oligodendrocytes, microglia, ependymal cells
glia in PNS?
schwann cell and satellite cells
what is astrocytes?
star-shaped, covers capillary, anchors neuron to capillary, metabolizes neurotransmitter, regulates Ca++ and K+, half neural tissue
oilgodendrocytes?
forms myelin sheath
ependymal?
forms membrane of epithelial tissue, produces CSF
microglia?
macrophages (WBC), clean up dead neurons
satellite cells?
support ganglia
schwann cells?
myelin sheath on axon
grey matter =
unmyelinated cell body
white matter =
myelinated axons
what are the electrical signals in neurons?
action potentials and local graded potentials
membrane ion channels in neurons?
active (gated) channels and passive (leakage) channel
what is active (gated) channels?
can be open/closed 1. voltage-gated 2. ligand-gated 3. mechanically-gated
what is leakage channel?
opens randomly, more K+ inside and Na++ outside
what is hyperpolarization
more negative then resting potential of -70 mv
what is depolarization?
membrane potential more positive
what occurs in the resting state?
Na+ channel closed and K+ channel closed, inactivation gate open activation gate closed
what occurs in depolarization phase?
Na+ channel activation gates open Na+ rushing into cell
what occurs in repolarization phase?
voltage gate K+ channel opens, Na+ channel inactivation gate closes, K+ leaves cell
what occurs in repolarization continue phase?
Na+ channel reset; inactivation gate reopens, K+ channel closed
what is propagated action potential?
the chances of Na+ travelling along axon and creating another action potential
type of propagations?
continuous conduction, saltatory conduction
what is continuous conduction?
slow occurs in unmyelinated fibers, one by one
what is saltatory conduction?
occurs in myelinated fibers, faster
Action potentials travel faster along?
larger diameter axons and myelinated axons
A fibers are largest
myelinated somatic sensory fibers, motor fibers
B fibers are medium
myelinated visceral sensory fibers, autonomic preganglionic fibers
C fibers are smallest
unmyelinated sensory fibers
