Autonomic nervous system Flashcards
what is the ANS
involuntary efferent division of the PNS
what does the ANS control
muscles and glands
is the autonomic nervous system voluntary or involuntary
involuntary
what is the ANS activated by
centers in the spinal cord, brain stem, and hypothalamus
what part of the nervous system controls most visceral function in the body
ANS
autonomic nerve pathway
preganglionic fiber synapses with the cell body of the second neuron which lies within a ganglion
post ganglionic fiber innervates effector organ
cholinergic receptors
nicotinic receptors that are found in the postganglionic cell bodies in all autonomic ganglia
what do cholingergic receptors respond to
Ach released from both sympathetic and parasympathetic preganglionic fibers and adrenal medulla
what neurotransmitters are released in preganglionic fibers in the sympathetic and parasympathetic NS
acetylcholine
what does acetylcholine bind to
muscarinic or nicotinic receptors
parasympathetic postganglionic fibers release what NT
acetylcholine
what are cholinergic fibers
release acetylcholine a their ending
sympathetic post ganglionic fibers release what NT
norepinephrine
what are sympathetic post ganglionic fibers called
adrenergic fibers
where is norepinephrine released from in the sympathetic nervous system
adrenal medulla in small amounts
what does epinephrine bind to
alpha and beta receptors
what type of receptor does epinephrine bind to
beta 2
what type of receptor does norepinephrine bind to
alpha and beta 1
what type of receptor does Ach bind to in the parasympathetic pathway
muscarinic
what type of receptor does Ach bind to in the sympathetic pathway
nicotinic (skeletal muscle)
what are some of the autonomic effectors
smooth and cardiac muscle
some endocrine and exocrine glands
some adipose tissue
what type of glands are the adrenal medulla
endocrine
what is the outer part of the adrenal gland called
adrenal cortex
what is the inner portion of the adrenal medulla called
adrenal medulla
the adrenal medulla is a modified part of the sympathetic ganglion that does not give rise to what
post ganglionic fibers
-must go through adrenal medulla which released epinephrine into the blood which goes to the effector
what does the adrenal gland do upon stimulation by the preganglionic fiber from the CNS
secretes catecholamines into the blood
what percentage of hormone output from the adrenal gland is norepinephrine
20%
what percentage of hormone output from the adrenal gland is epinephrine
80%
sympathetic dominance
fight or flight
promotes response that prepares the body for strenuous physical activity in emergency or stressful situation
adrenergic receptors (sympathetic) major classes (two)
alpha and beta
norepinephrine mainly excited which adrenergic receptor
alpha( but can excite beta to lesser extent)
epinephrine excites which adrenergic receptor
both alpha and beta equally
what does beta 1 activation help with
increasing heart rate and contractility in the heart
increasing stroke volume and cardiac output
what does activation of beta 2 help with
bronchiodilation in the lungs
what does activation of alpha 1 help with
smooth muscle contraction and glycogenolysis
cause vasoconstriction
parasympathetic dominance
dominated in quiet, relaxed situations
-body has housekeeping activities
-rest and digest bodily functions
muscarinic cholinergic receptors are found in which system
parasympathetic
are visceral organs innervated by sympathetic or parasympathetic nerve fibers
both
what is dual innervation
innervation of a single organ by both branches of the autonomic nervous system
when both systems (para and sympathetic) are active what is that called
tone
*different from dominance
when does system dominance occur
when fibers rate of firing to an organ increases above tone level
autonomic neuropathy or dysautonomia
nerves of the ANS are damaged and causes autonomic system dysfunction
what are some effects of dysautonomia
blood pressure, temp control, digestion, bladder function, sexual function, exercise intolerance, sweating problems
what can be the cause of dysautonomia
diabetes (neuropathy)
amyloidosis
autoimmune diseases
medications (chemo drugs)
inherited disorders (familial dysautonomia)
what is amyloidosis
irregular protein buildup in organs
Horner syndrome
rare disorder resulting from interruption of the pre or postganglionic sympathetic innervation to the face
what is the cause or Horner syndrome
injury to the nerves, injury to the carotid artery, stroke or lesion in the brainstem
what is the hallmark of Horner syndrome
triad of reduced sweating (anhidrosis), drooping eyelids (ptosis), and constricted pupils (miosis)
what is the treatment for Horner syndrome
there is no specific pharmacologic treatment
autonomic agonsit
binds to the neurotransmitters receptor and causes the same response the neurotransmitter would
natural agonists
endorphins
neurotransmitters
agonist drug examples
nicotine
morphine
heroin
LSD (lysergic acid diethlamide)
autonomic antagonist
binds with the receptor preventing the neurotransmitter from binding and causing a response
examples of autonomic antagonist
atropine, metoprolol, prazosin, antibodies for myasthenia gravis
atropine
blocks the effects of Ach at the muscarinic receptor but doesn’t affect nicotinic receptors
metroprolol
selectively blocks beta 1 receptors
prazosin
selectively blocks alpha 1 receptors
importance of the vagus nerve
sends signals from the brain to all other organs in the body and is in constant communication with heart lungs and gut
what is the vagus nerve responsible for
regulating stress response
what does lower vagal tone indicate
higher levels of anxiety and depression
the ability to change vagal tone can influence what
our mental health
