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What areas receive Ach as a neurotransmitter?
- 1) All parasympathetics
- 2) Adrenal Medulla
- 3) Sympathetic Sweat glands
- 4) Somatic skeletal muscle
Ach role in Enteric Nervous system?
Increase peristalsis and acid secretion
Role of NE and Epi in the enteric nervous system?
Inhibit peristalsis and acid secretion
What is the major excitatory NT of the enteric nervous system?
What is the role of Substance P and ATP in the enteric nervous sytstem?
Contribute to excitation
Role of NO, VIP and ATP in the Enteric nervous system?
What is the role of the myenteric and Auerbach's plexus in the Enteric Nervous system?
- Myenteric: contraction & relaxation
- Auerbach's: secretion, absorption & BF
5 Steps of Neurotransmitter release
- 1) Synthesis
- 2) Storage: in vesicles
- 3) Release: due to increased calcium
- 4) Receptor activation: Pre or Post-synaptic
- 5) Termination of action: Enzyme destruction or reuptake
Role of Vesamicol?
Block uptake of Ach into the vesicle
Role of Botulinum Toxin?
Inhibit release of Ach from presynaptic cleft vesicle
Role of AchE?
Break down Ach after function is complete back to cholien and acetate
Role of Hemicholinium?
Block reuptake of Choline
What is the rate limiting step in the production of NE?
Conversion of Tyrosine to L-dopa using Tyrosine hydroxylase
Role of Metyrosine?
Stop hydroxylation of tyrosine to L-dopa
What activates Tyrosine hydroxylase activity?
Increased sympathetic activity
Role of Reserpine?
Block uptake of Dopamine, NE or Epi into vesicles
Role of Antidepressants and Cocaine on NE?
Block reuptake by NET
Role of Guanethidine in adrenergic transmission?
Inhibits release of NE
Role of Amphetamines and Tyramine for adrenergic transmission?
Increase release of NE
Role of MAO?
Break down NE in nerve terminal
Role of COMT?
Break down circulating NE
What is the role of 3-methoxy-4-hydroxy-mandelic acid (VMA) ?
24-hr uring sample used to measure NE and Epi metabolism
Name the three common ion channels
Na, Ca & K
What is cleaved to activate Adenylyl Cyclase pathway?
GDP to GTP
Roles of IP3 and DAG from the Gq pathway?
- IP3: release stored calcium
- DAG: activate PKC
Role of Heteroreceptors:
Presynaptic Alpha2 receptor
Presynaptic Beta receptors
Presynaptic M2 receptors
- Presynaptic Alpha2 receptor: inhibit NE release
- Presynaptic Beta receptors: increase NE release
- Presynaptic M2 receptors: inhibit NE release
Four organs not affected by Parasympathetic system?
- Adrenal medulla
- Sweat glands
- Blood vessels
What is the main role of parasympathetics?
- Rest and Digest:
- Heart slows
- secret gastric acid
- GI motor activity
- relax sphintors
- constrict pupil
- constrict ciliary muscles
- decrease intraocular pressure
- Bronchioles constrict
- contract uterus
What is the main role of sympathetics?
- Fight or flight:
- constrict sphinctor
- dilate pupil
- Bronchioles dilate
- relax ciliary muscles
- increase HR
- vasoconstric arterioles
- vasodilate arteries to Sk.mm
- Increase Renin
- relax GI
- Relax & contract Uterus
How does the baroreceptor system function for high HR?
- 1) High BP = afferent impulse to VMC
- 2) Decrease SNS impulse = Vasodilation of arterioles
- 3) Increase PNS impulse via Vagus N = decreased HR via M2
How does the baroreceptor system function for low BP?
- 1) NE stimulates alpah receptors
- 2) vasoconstriction of arterioles - alpha receptors
- 3) increased heart rate - B1 receptors
- 4) HR increases
What is the role of Ach on HR and BP?
Will cause both to drop
Role of Ach in the bronchioles
Role of isoproterenol?
increase HR if there is an extreme drop
What receptors contract radial muscles, what Autonomic system?
Does dilation cause a huge effect on accomodation of lens shape?
No, only PNS activation via M3 receptors that constrict via radial muscles
Role of Beta receptors in eye?
- 1) increase aqueous humor
- 2) increase intraocular pressure
- 3) relax ciliary muscles