Physiology Review Flashcards
What is the function and alternative name of the Myenteric Plexus?
Function: Motility
AKA: Auerbach’s Plexus
Mnemonic: Myenteric Motility
What is the function and alternative name of the Submucosal Plexus?
Function: Ion and Fluid Transport
AKA: Meissner’s
Mnemonic: Submucosal Meissneir’s
What are the exceptions of Autonomic Innervation that have only** **Sympathetic Innervation?
Hair follicles
Thermoregulatory sweat gland
Liver
Adrenal gland
Kidney
Mnemonic: Symply Hair TALK
Where do sympathetic and parasympathetic produce similar rather rather than opposing effects?
Salivary Glands
What neurotransmitter stimulates all pre-ganglinic receptors and what receptor type are they?
Acetylcholine stimulates all pre-ganglionic receptors, which are all Nicotinic Receptors
What is the sympathetic organ that is the exception to the rules and what type of receptors does it have?
Sweat Glands
-Has Muscarinic receptors that respond to Acetylcholine
What two locations do not have post ganglionic fibers?
Adrenal Medulla
Skeletal Muscle
What determines the action of an organ?
Dependent on type of receptor, as well as what is secreted by the POST GANGLIONIC fibers
What effect would be caused by blocking the autoreceptors of a nerve terminal?
INCREASE in effect
(Homotropic Interaction)
What are some mechanisms of withdrawl rebound hyperactivity/disuse hyperactivity?
- Proliferation of receptors
- Loss of mechanisms for removal of transmitter
- Increased post-junctional responsiveness
What is Neuropeptide Y (NPY) a good example of?
A neurotransmitter (works on own specific receptor) and a neuromodulator (modulates the release of other molecules)
How do Hemicholiniums effect Cholinergic Transmission?
Choline Carrier Blocker
-Block the ***Synthesis*** of Ach
Mnemonic: Hemicholiniums block Choline carriers
How does Vesamicol (VAT) effect Cholinergic Transmission?
Acetylcholine Carrier Blocker
-Block the ***Storage*** of Ach
How does Botulinum Toxin effect Cholinergic Transmission?
Inhibits SNAPs
***Blocks the ***Release*** of Ach
Mneomnic: “Ohhhh SNAP, you got poisoned!”
How does Neostigmine effect Cholinergic Transmission?
It’s an Anticholinesterase inhibitor
Blocks ***Termination of Action_***_ of AchE
What is the function of M3 receptors in the Eye? What does Muscarinic Antagonism cause?
Constricts the Sphincter and Ciliary Muscle
***Miosis/Opens Canal of Schlemm***
Antagonism: causes paralysis of accomodation (Cycloplegia)
What effect does activation of M2 receptors have on the Heart?
DECREASED:
-Heart Rate (negative chronotropy) SA Node
-Conduction Velocity AV node
-Atrial Contraction
-Ventricular Contraction (Weak effect)
What effect does activation of M3 receptors have?
Bronchi/Bronchioles –> Contraction / BronchoSPASM
Bronchiolar Submucosal Gland –> Secretion –> NARROW lumen
***NEVER USE M3 Receptor agonists on people with ASTHMA***
Stomach –> INCREASED motility/cramps
Glands (M1, M3) –> Secretion (sweat, salivation, lacrimation)
Intestine –> Contraction (diarrhea, fecal incontinence)
Bladder –> Contracts Detrusor, Relaxes trigone/sphincter –> VOIDING, INCONTINENCE
Sphincters –> RELAXED (except LES)
What happens if you damage the endothelial cell layer (M3-rich) in blood vessels?
Will get vasoCONSTRICTIONdue to lack of endothelium-derived relaxing factor (i.e. no N.O. release) andunopposed action of vascular smooth muscle
(e.g. Cigarettes, Post-prandial)
What type of protein is the Muscarinic Receptor? Nicotinic Receptor?
Muscarinic: G-protein
Nicotinic: Ion Channel
What types of Receptors do the Adrenal Medulla, Autonomic Ganglia, and Neuromuscular Junction have?
Adrenal Medulla –> NN (Secretion of Epi and NE)
Autonomic Ganglia –> NN (Stimulation - Net effects depend on PANS/SANS innervation/dominance)
Neuormuscular Junction –> NM (Stimulation - Twitch/hyperactivity of skeletal muscle)
Direct vs Indirect Cholinomimetics
Direct: bind directly to muscarinic/nicotinic receptors
Indirect: produce effects by inhibiting Acetylcholinesterase (AchE)
What molecule blocks Tyrosine Hydroxylase in Catecholamine Synthesis?
Metyrosine
What is the immediate precursor of Norepinephrine and where does NE’s synthesis occur?
Dopamine
-Synthesis continues in the storage vesicles
Which part of Adrenergic Transmission does Reserpine effect?
Blocks Vesicular Monoamine Transporter (VMAT) during the Catecholamine STORAGE step
Mnemonic: MAT rides the pine
How does Bretylium affect Adrenergic Transmission and at what stage?
Bretylium inhibits VAMP
Effects the Catecholamine Release step
Mnemonic: Brett gets so AMPed up, bro! ;)
How is Adrenergic Transmission Terminated? (3 ways)
- Diffusion (at synapse; metabolized by liver Catechol-O-Methyl Transferase (COMT))
- Autoreceptor –> Decreased release
-
Re-Uptake via NET1 (NE transporter)
- Repackaged in vesicles
- Metabolized by Mitochondrial Monoamine Oxidase (MAO)
Gq Receptor Activation Mechanism
H1, a1, V1, M1, M3 Receptor – Gq –> Phospholipase C –> PIP2 produces IP3 (increased Ca++) and DAG (PKC activation)
Mnemonic: HAV an M&M (or 3)
Gs Mechanism of Receptor Activation
B1 B2 D1 H2 V2 Receptor –Gs–> Adenylyl Cyclase –> ATP –> Increased cAMP –> Increased PKA Activity
mnemonic: BBD stimulates 2HV
Gi Mechanism of Receptor Activation
M2 a2 D2 Receptor –Gi–| (Inhibited) Adenylyl Cyclase –> Decreased cAMP –> Decreased PKA Activity
Mnemonic: Don’t get 2 MAD
a1 Responses to Adrenoceptor Activation
Eye (Radial/Dilator muscle) –> DILATION (Mydriasis) due to contraction of Dilator muscle
Arterioles (skin, viscera) –> Contraction (INCREASED TPR, Diastolic Blood Pressure, Afterload) –> Reflex Bradycardia
Veins –> Contraction (INCREASED Venous Return, Preload)
Bladder Trigone/Sphincter –> Contraction ***Urinary RETENTION***
Male Sex Organ –> Ejaculation (Vas Deferens)
Liver –> Increased glycogenolysis
Kidney –> DECREASED Renin release (opposite to B1)
a1 effect on the Heart
Makes the heart work HARDER
a2 Receptor Response to Activation
***Autoreceptor at Nerve Terminal***
Prejunctional Nerve Terminal –> DECREASED release and NE synthesis
Platelets –> Aggregation
Pancreas –> DECREASED Insulin secretion
B1 Receptor Activation Effects
Heart –> INCREASED Heart Rate (chronotropy), Conduction Velocity (dromotropy), Force of Contraction (inotropy), Cardiac Output, Oxygen Consumption, and Automaticity (His-Purkinje)
Kidney –> INCREASED Renin Release (opposite to a1)
B2 Receptor Activation Effects
Blood Vessel (ALL) –> VasoDILATION (Decreased TPR, Diastolic Blood Pressure, Afterload) ***opposite of a1***
Uterus –> Relaxation
Bronchioles –> Dilation
Skeletal Muscle –> INCREASED glycogenolysis and contractility (tremor)
Liver –> INCREASED glycogenolysis (same as a1)
Pancreas –> INCREASED insulin secretion (opposite of a2)
What is the general effect of B2 receptor activation?
RELAXATION
D1 (Peripheral) Receptor Activation Effects
Renal, Mesenteric, Coronary Vasculature –> VasoDILATION** which leads to INCREASED GFR, RBF & Na+ excretion
***Treats URINARY RETENTION***
How does atropine effect the M3 receptors of the Eye?
INHIBITS them, leading to Dilation and no response to PEN LIGHT
