chapter 12 test Flashcards
afferent division
carries sensory info from PNS to CNS
efferent division
carries motor commands from CNS t PNS
somatic nervous system
controls voluntary and involuntary muscle skeletal contractions (efferent)
autonomic nervous system (ANS)
controls subconscious actions, contractions of smooth muscle and cardiac muscle, and glanduar secretions
sympathetic division (ANS)
stimulating effect
parasympathetic (ANS)
relaxing effect
perikaryon
neuron cytoplasm
cytoskeleton
neurofilaments and neurotubules
neurofibrils
bundles of neurofilaments that provide support for dendrites and axon
NISSL BODIES
dense areas of RER and ribosomes that make neural tissue appear gray
axoplasm
cytoplasm of axon
axolemma
specialized cell membrane tht covers the axoplasm
anaxonic neurons
small, all cell processes look alike, found in brain and sense organs
bipolar neurons
smal, 1 dendrite, 1 axon, found in special sensory organs (sight, mell, hearing)
unipolar neurons
pseudounipolar neurons, very long axons w fused dendrite and axon and cell body off to the side, found in sensory neurons of PNS
multipolar neurons
long axons, multiple dendrites and 1 axon, common in the CNS and includes all skeletal muscle motor neurons
sensory neurons
affernt neurons of the PNS, unipolar, monitor internal environment (visceral sensory neurons) and external environment (somatic sensory neurons)
interceptors
sensory receptor that monitors internal systems (digestive, respiratory, cardiovascular, urinary, reproductive) and internal senses (taste, deep pressure, and pain)
exteroceptors
sensory receptors for external senses (touch, temp, pressure) and distance senses (sight, smell, and hearing)
proprioceptors
sensory receptor that monitors position and movement
motor neuron
efferent neuron of PNS, part of somatic nervous sys, autonomic nervous sys, uses 2 groups of efferent axons-preganglionic and postgangliotic fibers
interneurons
association neurons located in brain, spinal cord, and autonomic ganglia, responsible for dist of sensory info and motor coordination, involved in memory, planning , and learning
4 types of neuroglia
ependymal cells, astrocytes, oligodendrocytes, microglia
ependymal cells
cells w highly branched process, contact neuroglia directly, form epithelium (ependyma), line central canal of spinal cord and ventricles of the brain, secretes cerebral spinal fluid
astrocytes
large cell bodies w many processes, maintain blood brain barrier
oligodendocytes
smaller cell bodies w fewer processes, myelinate CNS axons, provide structural framework
microglia
migrate through neural tissue cleaning up debris, wase products, and pathogens
satellite cells
amphicytes, surround ganglia and reg. environment around neuron
Schwann cells
neurilemma cells, form myelin sheath
5 main membrane processes
- resting potential 2. graded potential 3. action potential 4.synaptic activity 5. information processing
passive channels
leak channels, always open, permeability changes w conditions
4 steps in generation of action potentials
- depolariztion to threashold
- activation of Na channels
- inactivation of Na channels and activation of K channels
- return to normal permeability
Type A fibers
myelinated, large diameter, high speed, carry info to/from CNS, position, touch, balance, and motor impulses
Type B fibers
myelinated, med diameter, medium speed, sensory info, periphreral effectors
Type C fibers
unmyelinated, small diameter, slow speed, involuntary muscle, gland control
excitatory neurotransmitters
cause depolarization and promote action potentials
inhibitory neurotransmitters
cause hyperpolarization andsuppress action potentials
norepinephrine
released by adrenergic synopses, excitatory and depolarizing effect, fight or flight
dopamine
CNS neurotransmitter, may be ecitatory or inhibitory, involed in parkinsons and cocaine use
serotonin
CNS neurotransmitter, efects attention and emotional states, converts to melatonin in the brain
GABA
always inhibitory, not well understood
neuromodulators
other chem released by synaptic terminals, effects are slower to appear and long term
neuropeptides
neuromodulators that bind to receptors and activate enzymes
opiods
neuromodulators that bind to same receptors as morphine or opium and releeive pain
4 classes of opioids
- endorphins
- enkephalins
- endomorphine
- dynorphins
excitatory postsynaptic potential (EPSP)
graded depolarization of postsynaptic membrane
inhibitory postsynaptic potential (IPSP)
graded hyperpolarization of postsynaptic membrane