Autonomic Nervous System Flashcards
What are the areas of the brain that control the autonomic nervous system?
-hypothalamus
-pons
-medulla
-midbrain (not as much)
What are the two divisions of the autonomic nervous system?
parasympathetic and sympathetic
Which of the two divisions of the ANS is typically active at rest?
parasympathetic
Characteristics of the sympathetic nervous system:
-fight or flight
-can selectively activate effectors of elicit a mass discharge
-noradrenergic/adrenergic
Characteristics of parasympathetic nervous system:
-rest and digest
-control mechanisms are almost always specific, activating or inhibiting discrete targets
-cholinergic (ACH)
Where are parasympathetic neurons found exiting and entering the spinal cord?
craniosacral regions
Where are sympathetic neurons found exiting and entering the spinal cord?
thoracolumbar
Are organs typically innervated by both the parasympathetic or sympathetic, or just one division?
typically both b
What are ganglia?
group of neuronal cell bodies outside the CNS
What cranial nerves have parasympathetic fibers?
III, VII, IX, and X
What is releases at every preganglionic terminal?
ACH
What type of receptors does ACH bind to?
nicotinic receptors
What type of response does the release of ACH cause in the postganglionic neuron?
EPSP
Where do the sympathetic neurons synapse?
-synapse at the ganglia at the level it leaves the spinal cord
-move up or down and synapse at a different ganglia
-pass through the chain and out a sympathetic nerve and synapse at a peripheral ganglia
exception to the synapsing rules:
sympathetics in the adrenal medulla
What is released from most sympathetic postganglionic nerves?:
NE (norepinephrine )
What are two of the exceptions to the rule that all post ganglionic sympathetic fibers release norepinephrine?
-ACH releases at sweat glands
-ACH released at some skeletal muscle vasculature
Where does the ACH bind to on the effector?
alpha or beta receptors
What special type of cell is present in the adrenal medulla that released epinephrine/norepinephrine right in to the blood stream?
chromaffin cells
How can the adrenal medulla release epinephrine straight into the blood stream?
because it has a special enzyme that turns norepinephrine into epinephrine
Do alpha or beta receptors have a higher affinity for catecholamines?
beta receptors
What do alpha 1 receptors do?
constrict smooth muscle
-increase in IP3
-causes a release in extra calcium
What do alpha 2 receptors cause?
block further norepinephrine release
-cause muscle contraction
What has a higher affinity for beta 1 receptors, Epi or NE?
almost equal
What has a higher affinity for beta 2 receptors, Epi or NE?
epi has a MUCH greater affinity than NE
What has a higher affinity for beta 3 receptors, Epi or NE?
NE has a slightly higher affinity than epi
Why is EPI given if you are having an allergic reaction?
has a high affinity for beta 2 receptors which are responsible for dilating airways
What do beta 1 receptors do?
increase heart rate and contractability, increase lipolysis, increase renin secretion, and increase protein content in saliva
What do beta 2 receptors do?
relax smooth muscle, release FA and glucose
-relax smooth muscles
-increase glycogenolysis
where are beta 3 receptors found?
found in adipose tissue
-increase lipolysis
Where are alpha 1 receptors located?
effector tissues, smooth muscles, glands
Where are alpha 2 receptors located?
nerve endings, some smooth muscle
Where are beta 1 receptors located?
cardiac muscle, juxtaglomerular apparatus
Where are beta 2 receptors located?
smooth muscle, liver, and heart
Why is epinephrine added to local anesthetics?
causes vasoconstriction via alpha 1 receptors
-does not allow local anesthetic to diffuse as far and allows for more pain suppression in the are it is injected
How does albuterol work?
it is a beta 2 selective agonist and cause bronchodilation
How can NE be removed from the synapse?
-diffusion from synaptic cleft
-reuptake by presynaptic terminal
-destruction by MOA or COMT
What does cocaine do to the NE at the synapse?
blocks the reuptake by the presynaptic terminal
What are MOA inhibitors used for?
treat parkinsons, depression, social anxiety, and others
What are some side effects of MAO inhibitors?
xerostomia and nausea
Are preganglionic neurons longer in sympathetic or parasympathetic?
parasympathetic
What NT is released from preganglionic parasympathetic neurons?
ACH
What receptors does ACH bind to?
nicotinic
What type of receptors are muscarinic receptors?
G protein coupled receptors
What do muscarinic receptors do ?
constrict smooth muscles, relax sphincters, and stimulate glandular secretions
D-digestion
U- urination
M- miosis
B-bronchoconstriction and bradycardia
L- lacrimation
S- salivation
Where are M1 receptors?
stomach and salivary glands
Where are M2 receptors?
smooth muscle, myocardium, cardiac autorhythmic cells
Where are M3 receptors?
exocrine glands, smooth muscle, endometrium, sweat glands
Where are M4 receptors?
CNS and vagal nerve
Where are M5 receptors?
CNS
What do anticholinergic drugs do?
block ACH from binding to the receptors and activating them
What does the M2 receptor do in urination and the GI tract?
relax sphincter
What does the M3 receptor do in urination and the GI tract ?
constrict detrusor in bladder and constrict muscles in GI
What does alpha1 do in urination and the GI tract?
constrict sphinter
What does beta 2 in urination and GI tract ?
relax detrusor and muscles in the GI
What do M1 and M3 receptors do in the salivary glands
stimulate lots of watery secretions due to contraction of myoepithelial cells and vasodilation
What do alpha 1 and beta 2 receptors do in the salivary glands?
vasoconstriction and secretion of concentrated saliva and stimulate secretion of protein
What does meth do?
acts on alpha adrenergic receptors and cause vasoconstriction and reduce salivary flow, depriving the oral cavity of saliva’s buffering activty
What controls the diameter of vascular smooth muscle/blood vessels?
sympathetic nervous system
-alpha 1 causes vasoconstriction
-beta 2 causes vasodilation
What receptors act on the heart?
PNS
-M2
SNS
-B1 and B2 `
What receptors act on the lungs?
PNS
-M3
SNS
-B2
