ANS Flashcards
Neurotransmitters
- Somatic nerves to skeletal muscle: Ach
- Preganglionic nerve to adrenal medulla: Ach
- Preganglionic nerve to sympathetic nerves: Ach
- Preganglionic nerve to parasympathetic nerves: Ach
- Parasympathetic nerves to exocrine glands, heart, smooth muscle: Ach
- Sympathetic nerve to exocrine glands, heart, smooth muscle: NE
Receptors
Nicotinic: at skeletal muscle, adrenal medulla, preganglions at sympathetic and parasympathetic
Muscarinic at: exocrine glands, heart, smooth muscle
alpha 1: NE at smooth muscle
beta 2: smooth muscle
beta 1: NE at heart
Sympathetic ganglion
-preganglionic nerves between thoracic and lumbar region
Fight or flight
**Chain ganglion- responses are all or nothing! “thick if need to run away, need everything turned on at once”
Parasympathetic ganglion
-Preganglionic nerves at cervical and sacral region
*Vagus is major player
Rest and digest
-discrete activation- not everything is needed at once
Baroreceptor Reflex
Increase in arterial pressure, stretches stretch receptors in aortic arch and carotid artery
Increase parasympathetic on heart, decreases HR, decreases CO, and decrease CO=decrease BP
Decrease sympathetic on vasculature= vasodilation
Agonist
-substance that binds to a receptor and activates it
-can be an exogenous chemical
-mimics action of endogenous ligand
Antagonist
-binds to receptor and blocks its activation/effect
>blocks drugs (reversals) or endogenous activators
Parasympathetic vs. sympathetic system
-In opposition with each other
-One ANS system will have predominant tone over the other in a given organ
-blocking one system often unmasks activity of opposing system
Parasympathetic impact on arteries?
None!
BP/vasoconstriction in arterioles based on sympathetic. Will always have some firing to arteries, and then if need more, then more will fire
Ach
-bind to cholinergic receptors; two major subtypes:
1. Muscarinic receptors (M1-M5)- heart, smooth muscle, axocrine glands)
2. Nicotinic receptors (NM , NN)- skeletal muscle and ganglia
Drugs for muscarinic effects
None formulated
-these drugs tend to be “dirty”, because they target so much
Drugs for nicotinic receptors
-drugs present that can select for specific subtypes of nicotinic receptors
NE and Epi
bind to Adrenergic receptors; two major subtypes:
-alpha adrenergic (alpha1, 2)
-beta adrenergic (beta 1,2,3)
What does sympathetic stimulation cause?
- Increased heart rate
2.decreased gastric motility
3.vasoconstriction - Decreased micturition
Sympathetic in Eye
-alpha1: Dilate pupils (let in light)
-beta 2: Relax ciliary muscle (allows animal to see far away)
Parasympathetic in eye
-M3, M2- pupil constriction AND contraction of ciliary muscle
**allows animal to focus nearby on food… rest and digest
Sympathetic in head glands
alpha 1: slight increase in secretion of lacrimal and salivary glands
**dry, thick feeling
Parasympathetic in head glands
M3: large increase in secretion of lacrimal and salivary glands
**watery, viscous
Sympathetic stimulations causes:
-vasoconstriction
-increases heart rate
-decreased gastric motility
-inhibit micturition
Parasympathetic stimulation causes
- decreased heart rate
- micturition (still voluntary control but will have increased urge)
-increased gastric motility
**only sympathetic innervates arterioles= therefore no impact on vessels
Sympathetic stimulations in lungs
**targets bronchiolar smooth muscle
-Bronchiolar dilation (more air into the lungs)
-Receptor: beta 2; need very large stimulation
Parasympathetic stimulations in lungs
**targets bronchiolar smooth muscle
-Contraction
-Receptor: mostly M3, some M2
Sympathetic stimulation on heart
Increased heart rate in SA node, contractility of atria and ventricles, automaticity of AV node
Receptor: mostly Beta 1, some beta 2
**goes to both pacemakers and diffusely throughout the heart
Parasympathetic stimulation on heart
-Decrease in HR on SA node, decreased contractility on ventricles and atria, decreased conduction of AV node
Receptor: M2
**targets just pacemakers
Vocabulary for cardiac changes
- chronotrophic- heart rate
- inotrophic= contractility/force
- dromotropic= speed of conduction
- lusotropic= relaxation
Stimulation of blood vessels
-Sympathetic
-mostly alpha 1; results in constriction
-beta 2 results in dilation
**no parasympathetic stimulation
Sympathetic stimulation on GI tract
-alpha and beta 1 and 2= decreased motility
- alpha 1= increased sphincter tone
-alpha 2= inhibition of secretion
Parasympathetic stimulation of GI tract
M2 M3 receptors: increased motility
M3, M2 receptors= decreased sphincter tone
M3, M2 receptors= increased stimulation secretion
Sympathetic stimulation on urinary bladder
beta 2= relaxation of detrusor muscle (less likely/more difficult to urinate)
alpha 1= contraction of sphincters
Parasympathetic stimulation on bladder
M3= contraction of detrusor muscle (more likely/less difficult to urinate)
M3= relaxation of sphincters
Sympathetic stimulation on sex organs
alpha 1 males: ejaculation
Parasympathetic stimulation on sex organs
M3= erection
sympathetic stimulation of skin
Sympathetic: alpha one effects sweat glands and pilomotor muscles
Parasympathetic: M3
Sympathetic stimulation of adrenal medulla
NN receptors (Ach targeting nicotinic; synapses directly on adrenal medulla) results in secretion of EPI
**no parasympathetic
Sympathetic stimulation of Kidney
beta 1= increased secretion of renin
**no parasympathetic stimulation
Sympathetic stimulation of liver
alpha 1= glycogenolysis
beta 2= gluconeogenesis
**no parasympathetic stimulation
Sympathetic stimulation of splenic capsule
alpha 1= contraction of splenic capsule
Sympathetic stimulation on sympathetic nerves
alpha 2= inhibition of NE release from autoreceptor
ANS receptor signal transduction for betas
- beta receptors are linked with G-receptors (GB type), leading to activation of adenylyl cyclase
- Activates cAMP
- increased biological effect
ANS receptor signal transduction for alphas
- alpha receptors are linked with G-receptors (Gi type)
- inhibits adenylyl cyclase activation
3.decreased in cAMP activation - decreased biological effect
