ANS Flashcards
Describe pre/post ganglia for SNS.
- short pre/long post
- pre cell bodies in thorocolumbar division (T1-L2/L3) in intermediolateral horn of grey matter
- post cell bodies in paravertebral and prevertebral (celiac/sup/inf mesenteric ganglia) columns
Describe pre/post ganglia for PSNS.
- long pre/short post
- pre cell bodies in cranio-sacral = CN 3/7/9/10 and s2-s4
- post cell bodies in target organs or discrete ganglia in head/necl (ciliary)
What is most important function of SNS
- vasomotor tone; regulates BP w/ changes in position, exercise, etc
- does multiple functions vs PSNS which is discrete, one at a time/selective
Describe a SNS innervated receptor for blood vessel
-preganglia causes release of ACH onto NICOTINIC receptor then postganglia causes release of NE into blood stream
Describe a SNS innervated receptor for sweat glands
-preganglia causes release of ACH onto NICOTINIC receptor then postganglia causes release of ACH onto a MUSCARINIC receptor
(same as PSNS but sweat glands are only innerv by SNS)
Describe a SNS innervated receptor for adrenal medulla
-preganglia causes release of ACH onto NICOTINIC receptor directly on medulla which then acts as ganglia and releases NE (20%) and Epi (80%)
Describe a PSNS innervated receptor for
-action potential causes release of ACH onto NICOTINIC receptor which then causes release of ACH onto a MUSCARINIC receptor
Most organs have both PSNS and SNS innerv except for?
- sweat glands = only SNS (but muscarinic receptors present)
- blood vessels = only SNS
- ciliary eye muscles = only PSNS
- bronchial smooth muscle = only PSNS (but B2 receptors present)
If a receptor is present in a tissue but not innervated (nerve releases NT onto it), how is it activated?
-drug or hormone = something circulating in the blood
Describe how both SNS and PSNS have baseline tone at rest.
- SNS - baseline motor tone via blood vessels
- PSNS - heart rate via Vagus n.
What are the two main types of cholinergic receptors?
- nicotinic Ach (ligand gated) = nn (nerve), nm (skeletal)
2 muscarinic Ach (G protein) = M1-M5
What are the types of adrenergic receptors?
alpha 1, 2
beta 1,2,3
What are the endogenous catecholamines?
epi/NE/DOPA
What are the synthetic/exogenous catecholamines?
dobutamine/isoproteronol
What are the synthetic NON-catecholamines:
- indirect acting
- direct acting
- ephedrine, amphetamines, mephentermine
2. phenylephrine, methoxamine
What are the selective alpha-2 agonists?
clonidine, dexmedetomidine (precedex)
sedation/analgesia/
What are the selective beta-2 agonists?
albuterol, terbutaline, ritodrine