Chapter 11: The Nervous System Flashcards
nerve
bundle of axons and their sheaths that connects CNS to sensory receptors, muscles, and glands
sensory receptors
ends of neurons or separate specialized cells that detect sensations
ganglion
collection of neuron cell bodies outside CNS
plexus
extensive network of axons and sometimes neuron cell bodies, located outside CNS
somatic nervous system
CNS to skeletal muscles
voluntary
single neuron system
synapse
junctions of a nerve cell with another cell
autonomic nervous system
from CNS to smooth muscle, cardiac muscle, and certain glands
involuntary
two neuron system
sympathetic, parasympathetic, enteric
sympathetic
prepares body for physical activity
parasympathetic
regulates resting or vegetative functions, such as digesting food or emptying bladdar
sensory division of the PNS
afferent: transmits action potentials from receptors to CNS
Motor Division of the PNS
efferent: transmits action potentials from CNS to effectors
organization of neurons
- cell body: soma
- dendrites: input
- axons: output
sensory or afferent neuron
action potential toward CNS
motor or efferent neuron
action potential away from CNS
interneurons or association neuron
within CNS from one neuron to another
Multipolar
motor neurons
bipolar
sensory in retina of the eye and nose
astrocytes
nourish neurons
blood brain barrier
protects neurons from toxic substances, allows exchange of nutrients and wastes products between neurons and blood
ependymal cells
form choroid plexuses which secrete cerebrospinal fluid
microglia
specialized macrophages that respond to inflammation, phagocytize invaders
oligodendrocytes
sheet that forms and protects myelin sheaths that surround axon
Schwann cells
neuroglia in the PNS that wrap around axons, form myelin sheath around portion of one axon
satellite cells
surround neuron cell bodies in sensory ganglia, provide support and nutrients
Node of Ranvier
in myelinated axons, makes impulses faster
gray matter
unmyelinated axons, cell bodies, dendrites, neuroglia, integrative functions
white matter
myelinated axons. nerve tracts propagate actin potential from one area in the CNS to another
difference between presynaptic membrane and post synaptic membrane
presynaptic: cell membrane sending signal
postsynaptic: cell membrane receiving signal
leak channels
nongated ion channels are always open, very specific
What is the difference between graded potential and action potential?
graded: receptive area (dendrites, cell body), has ligand gated channels, where synapses are
Action: signal conducting area (axon), has voltage gated channels
Type A Nerve Fiber
large diameter, myelinated, conduct at 15-120 m/s
Type B Nerve fiber
medium diameter, light myelinated, conduct at 3-15 m/s
Type C Nerve Fiber
small diameter, unmyelinated, conduct 2 m/s or less
Electrical Synapse
gap junctions that allow a local current to flow between adjacent cells, allows neurons to act as one, common in cardiac muscle
synaptic vesicles
action potential causes Ca2+ to enter cell that causes neurotransmitter to be released from vesicles
