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