-
sheath of Schwann cell containing cytoplasm and nucleus that encloses myelin
neurilemma
-
corresponds to rough endoplasmic reticulum in other cells
chromatophilic surface
-
network of fine threads extending into nerve fiber
neurofibrils
-
substance of Schwann cell composed of lipoprotein that insultes axons and increases impulse speed
myelin sheath
-
neuron process with many branches that conducts an impulse toward the cell body
dendrite
-
branch of an axon
collateral
-
star-shaped neuroglia between neurons and blood vessels
astrocyte
-
nerve fiber arising from a slight elevation of the cell body that conducts an impuse away from the cell body
axon
-
transmits impulse from sensory to motor neurons within central nervous system
interneuron
-
transmits impulse out of the brain or spinal cord to effectors (muscles and glands)
motor (efferent) neuron
-
transmits impulse into brain or spinal cord from receptors
sensory (afferent) neuron
-
myelin-forming neuroglia in brain and spinal cord
oligodendrocyte
-
phagocytic neuroglia
microglia
-
structure capable of responding to motor impulse
effector
-
specialized mass of neuron cell bodies outside the brain or spinal cord
ganglion
-
cells that cover the inside spaces of the brain ventricles and help regulate cerebrospinal fluid
ependymal cell
-
What are the functions of the nervous system?
- receiving
- deciding
- reacting to stimuli
-
what are the structures of a neuron
- the cell body
- the dendrites
- the axon
- the axon terminals
-
functional connection between the axon of one neuron and the dendrite or cell body of another neuron or the membrane of another cell type
synapse
-
a narrow extracellular space between the presynaptic and postsynaptic neurons
synaptic cleft
-
tiny enlargement at the end of an axon that secretes a neurotransmitter
synaptic knob
-
contain many unmyelinated axons and neuron cell bodies
gray matter
-
groups of mylenated axons
white matter
-
structural support, formation of scar tissue, transport of substances between blood vessels and neurons, communicate with one another and with neurons
astrocytes
-
form myelin sheaths in the brain and spinal cord, produce nerve growth factors
oligodendrocytes
-
structural support and phagocytosis
microglia
-
form a porous layer through which substances diffuse between the interstitual fluid of the brain and spinal cord and the cerebrospinal fluid
ependyma
-
cell body with many processes, one of which is an axon, the rest dendrites
multipolar neuron
-
cell body with a process, arising from each end, one axon and one dendrite
bipolar neuron
-
cell body with a single proess that divides itno 2 branches and functions as an axon
unipolar neuron
-
which typye of neuron is most common in the brain or spinal cord?
multipolar neuron
-
conducts nerve impulses from receptors in peripheral body parts into the brain or spinal cord
sensory neuron
-
transmits nerve impulses between neurons in the brain and spinal cord
interneuron
-
conducts nerve impulses from the brain or spinal cord out to effectors-muscles or glands
motor neuron
-
What is resting potential and the approximate value in millivolts?
- one that is not sending impulses or responding to other neurons
- (-70) millivolts
-
sequence of electrical changes in part of a nerve cell membrane exposed to a stimulus that exceeds threshold
action potential
-
What occurs during polarization of a nerve fiber?
unequal distribution of positive and negative ions on either side of the membrane
-
increase in the negitivity of the resting potential of a cell membrane
hyperpolarization
-
nerve impulse conduction that seems to jump from one node to the next
saltatory conduction
-
communication of an impulse from one neuron to the next
synaptic transmission
-
if a neurotransmitter binds to a postsynaptic receptor and opens sodium ion channels, the ions diffuse inward, depolarizing the membranse, possibly triggering an action potential
excitatory postsynaptic potential
-
neurotransmitter binds other receptors and increases membrane permeability to potassium ions, these ions diffuse outward. hyperpolarizing the membrane
inhibitory postsynaptic potential
-
controls skeletal muscle actions; stimulates skeletal muscle contraction at neuromuscular junctions.
acetylcholine
-
creates a sense of well-being; low levels may lead to depression; may excite or inhibit autonomic nervous system actions, depending on receptors
norepinephrine
-
creates a snese of well being; deficiency in some brain areas associated with parkinson disease; limited actions in autonomic nervous sustem; may excite or inhibit, depending on receptors
dopamine
-
primarily inhibitory; leads to sleepiness; action is blocked by LSD, enhanced by selective seritonin reuptake inhibitor antidepressant drugs
serotonin
-
release in hypothalamus promotes alertness
histimine
-
Aminio Acids
-Generally inhibitory
GABA
-
Amino Acids
-generally excitatory
Glutamate
-
Neuropeptides
-Generally ingibitory; reduce pain by inhibiting substance P release
-
Neuropeptides
-excitatory; pain perception
substance P
-
Gases
-may play role in memory; vasodilation
Nitric Oxide
-
the more _____ that enters the synaptic knob, the more vesicles release neurotransmitters
calcium
-
If calcium is deficient in the blood, what happens to
the muscles?
the muscle continuously spasm
-
Which neurotransmitter imbalances are associated with Alzheimer disease?
acetylcholine
-
Which neurotransmitter imbalances are associated with Parkinson disease?
dopamine
-
Which neurotransmitter imbalances are associated with epilepsy?
excess GABA lead to excess norepinephrine and dopamine
-
Which neurotransmitter imbalances are associated with insomnia
deficient serotonin
-
Which neurotransmitter imbalances are associated with mania
excess norepinephrine
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