Peripheral nervous System Flashcards
autonomic nervous system
involuntary, innervates cardiac muscle, smooth muscle, glands, and organs
somatic nervous system
voluntary, innervates skeletal muscles
sympathetic nervous system
fight or flight
nerve fibers of sympathetic nervous system
short preganglionic originate in thoracic and lumbar regions
long postganglionic originate in ganglionic chain and end on effector organs
ganglion
end of a nerve fiber, secretes neurotransmitters
parasympathetic nervous system
rest and Digest
nerve fibers of parasympathetic nervous system
long preganglionic originate in cranial and sacral regions
short postganglionic originate in effector organs
cholinergic cells
release acetylcholine, The receptors include nicotinic and muscarinic
adrenergic cells
release norepinephrine, receptors include alpha 1, Alpha 2, beta 1 and beta 2
norepinephrine released by..
sympathetic postganglionic fibers
acetylcholine released by..
all preganglionic fibers and parasympathetic postganglionic fibers
dual innervation
most organs are innervated by both divisions of the autonomic nervous system, usually produce opposite effects in an organ, and allow precise control over an organs activity
dual innervation exceptions
most arterioles, veins, and sweat glands are innervated only by sympathetic nerve fibers
salivary glands are innervated by both divisions, but each division stimulates a different form of saliva
Adrenal medulla
a modified sympathetic ganglion, secretes 80% epinephrine comma and secretes 20% norepinephrine
medulla
directly responsible for autonomic output
autonomic reflexes
urination, defecation, and penile erection are integrated at spinal cord level
in the somatic nervous system, where do axons of motor neurons originate and end?
spinal cord or brain stem, and end on skeletal muscle
in the somatic nervous system, what kind of neurotransmitter do motor neurons release?
they release acetylcholine to stimulate muscle contractions
neuromuscular Junction
where an axon terminal of a motor neuron forms a junction with a muscle cell
sarcolemma
a membrane of muscle fiber
to end a muscle contraction..
acetylcholinesterase breaks down acetylcholine and recycles it, it in activates acetylcholine, ending the contraction
black widow spider venom
causes an excess release of acetylcholine
botulism toxin
blocks acetylcholine release
curare, a South American Plant substance
blocks acetylcholine receptor function
organophosphates
inhibit acetylcholinesterase
myasthenia gravis
an autoimmune disease that destroys acetylcholine receptors
