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neurons (hints and helps: book definitions)

Terms in this set (16)

ANS effectors
cardiac muscle, smooth muscle, and glands
sensory or efferent neurons
either contain sensory receptors at their distal ends or are located just after sensory receptors that are separate cells
sensory or efferent neurons
once an appropriate stimulus ctivates a sensory receptor, the sensory neuron forms an action potential in its axzon and the action potentail is conveyed into the cne through cranial or spinal nerves.
sensory or efferent neurons
most are unipolar in structure
nueroglia
astrocytes, oligodendrocytes, microglia, and ependymal cells
astrocytes
largest and most numerous of the nueroglia. for strength, support, provides a blood brain barrier, regulates growth, and helps maintain appropriate chemical environments
microglia
function as phagocytes,
somatic nervous system
consists of sensory neurons that convey info from somatic receptors in the head, body, wall, and limbs and from receptors for the special senses of vision, hearing, taste, and smell to the CNS and motor neurons that conduct impulses from the CNS to skeletal muscles only.
somatic effectors
the body's striated muscles (such as those found in the arm and back)
depolarization
the negative membrane potential becomes less negative, reaches zero, and then becomes positive.
repolarization
the membrane potential is restored to the resting state of -70 mV
after-hyperpolarization
following the repolarization phase, during withc the membrane potential temporarily becomes more negative than the resting level.
neurotransmitters
one of a vareity of molecules within axon terminals that are released into synaptic cleft in response to a nerve impulse and that change the membrane potential of the post synaptic neuron
neuropeptides
neurotransmitters consisting of 3-40 amino acids linked by peptide bonds, numerous and widespread throughout the CNS and PNS. Besides their role as neurotransmitters, many neuropeptides serve as hormones that regulate physiological responses elsewhere in the body.
catacholamines
a subgroup of biogenic amines; epinephrine, norepinephrine, and dopamine; inactivation occurs via reputake into synaptic end bulbs; then they are either recycled back into the synaptic vesicles or destroyed by the enzymes (MAO or COMT).
hyperpolarization
The interior of the neuron becomes more negative than the normal resting potential
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