Physiology Review

Question 1

What is the function and alternative name of the Myenteric Plexus?

Answer 1

Function: Motility

AKA: Auerbach’s Plexus

Mnemonic: Myenteric Motility

Question 2

What is the function and alternative name of the Submucosal Plexus?

Answer 2

Function: Ion and Fluid Transport

AKA: Meissner’s

Mnemonic: Submucosal Meissneir’s

Question 3

What are the exceptions of Autonomic Innervation that have only** **Sympathetic Innervation?

Answer 3

Hair follicles

Thermoregulatory sweat gland

Liver

Adrenal gland

Kidney

Mnemonic: Symply Hair TALK

Question 4

Where do sympathetic and parasympathetic produce similar rather rather than opposing effects?

Answer 4

Salivary Glands

Question 5

What neurotransmitter stimulates all pre-ganglinic receptors and what receptor type are they?

Answer 5

Acetylcholine stimulates all pre-ganglionic receptors, which are all Nicotinic Receptors

Question 6

What is the sympathetic organ that is the exception to the rules and what type of receptors does it have?

Answer 6

Sweat Glands

-Has Muscarinic receptors that respond to Acetylcholine

Question 7

What two locations do not have post ganglionic fibers?

Answer 7

Adrenal Medulla

Skeletal Muscle

Question 8

What determines the action of an organ?

Answer 8

Dependent on type of receptor, as well as what is secreted by the POST GANGLIONIC fibers

Question 9

What effect would be caused by blocking the autoreceptors of a nerve terminal?

Answer 9

INCREASE in effect

(Homotropic Interaction)

Question 10

What are some mechanisms of withdrawl rebound hyperactivity/disuse hyperactivity?

Answer 10

• Proliferation of receptors
• Loss of mechanisms for removal of transmitter
• Increased post-junctional responsiveness

Question 11

What is Neuropeptide Y (NPY) a good example of?

Answer 11

A neurotransmitter (works on own specific receptor) and a neuromodulator (modulates the release of other molecules)

Question 12

How do Hemicholiniums effect Cholinergic Transmission?

Answer 12

Choline Carrier Blocker

-Block the ***Synthesis*** of Ach

Mnemonic: Hemicholiniums block Choline carriers

Question 13

How does Vesamicol (VAT) effect Cholinergic Transmission?

Answer 13

Acetylcholine Carrier Blocker

-Block the ***Storage*** of Ach

Question 14

How does Botulinum Toxin effect Cholinergic Transmission?

Answer 14

Inhibits SNAPs

***Blocks the ***Release*** of Ach

Mneomnic: “Ohhhh SNAP, you got poisoned!”

Question 15

How does Neostigmine effect Cholinergic Transmission?

Answer 15

It’s an Anticholinesterase inhibitor

Blocks ***Termination of Action_***_ of AchE

Question 16

What is the function of M₃ receptors in the Eye? What does Muscarinic Antagonism cause?

Answer 16

Constricts the Sphincter and Ciliary Muscle

***Miosis/Opens Canal of Schlemm***

Antagonism: causes paralysis of accomodation (Cycloplegia)

Question 17

What effect does activation of M₂ receptors have on the Heart?

Answer 17

DECREASED:

-Heart Rate (negative chronotropy) SA Node

-Conduction Velocity AV node

-Atrial Contraction

-Ventricular Contraction (Weak effect)

Question 18

What effect does activation of M3 receptors have?

Answer 18

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)

Question 19

What happens if you damage the endothelial cell layer (M3-rich) in blood vessels?

Answer 19

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)

Question 20

What type of protein is the Muscarinic Receptor? Nicotinic Receptor?

Answer 20

Muscarinic: G-protein

Nicotinic: Ion Channel

Question 21

What types of Receptors do the Adrenal Medulla, Autonomic Ganglia, and Neuromuscular Junction have?

Answer 21

Adrenal Medulla –> N_N (Secretion of Epi and NE)

Autonomic Ganglia –> N_N (Stimulation - Net effects depend on PANS/SANS innervation/dominance)

Neuormuscular Junction –> N_M (Stimulation - Twitch/hyperactivity of skeletal muscle)

Question 22

Direct vs Indirect Cholinomimetics

Answer 22

Direct: bind directly to muscarinic/nicotinic receptors

Indirect: produce effects by inhibiting Acetylcholinesterase (AchE)

Question 23

What molecule blocks Tyrosine Hydroxylase in Catecholamine Synthesis?

Answer 23

Metyrosine

Question 24

What is the immediate precursor of Norepinephrine and where does NE’s synthesis occur?

Answer 24

Dopamine

-Synthesis continues in the storage vesicles

Question 25

Which part of **Adrenergic Transmission** does **_Reserpine_** effect?

Answer 25

Blocks **Vesicular Monoamine Transporter (VMAT)** during the Catecholamine **_STORAGE_** step Mnemonic: **MAT** rides the **pine**

Question 26

How does **_Bretylium_** affect **Adrenergic Transmission** and at **what stage**?

Answer 26

Bretylium inhibits **_VAMP_** Effects the Catecholamine **_Release_** step Mnemonic: **Bret**t gets so **AMP**ed up, bro! ;)

Question 27

How is **Adrenergic Transmission _Terminated_**? (3 ways)

Answer 27

1. _Diffusion_ (at synapse; metabolized by **liver** **_Catechol-O-Methyl Transferase (COMT)_**) 2. _Autoreceptor_ --\> **Decreased** release 3. _Re-Uptake_ via **NET1 (NE transporter)** - Repackaged in vesicles - _Metabolized_ by **_Mitochondrial Monoamine Oxidase (MAO)_**

Question 28

**G_q** Receptor Activation Mechanism

Answer 28

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)

Question 29

**G_s** Mechanism of Receptor Activation

Answer 29

B1 B2 D1 H2 V2 Receptor --**Gs**--\> Adenylyl Cyclase --\> ATP --\> **Increased cAMP** --\> **_Increased PKA Activity_** mnemonic: **BBD** **stimulates** **2HV**

Question 30

**G_i** Mechanism of Receptor Activation

Answer 30

M2 a2 D2 Receptor --**Gi**--| (**Inhibited**) Adenylyl Cyclase --\> **Decreased cAMP** --\> **_Decreased PKA Activity_** Mnemonic: **Don't** get **2 MAD**

Question 31

**a₁** Responses to Adrenoceptor Activation

Answer 31

_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**)

Question 32

**a₁** effect on the **Heart**

Answer 32

Makes the heart **work HARDER**

Question 33

**a₂** Receptor Response to Activation

Answer 33

\*\*\***_Autoreceptor_** at Nerve Terminal\*\*\* _Prejunctional Nerve Terminal_ --\> **DECREASED** release and _NE synthesis_ _Platelets_ --\> **Aggregation** _Pancreas_ --\> **DECREASED** _Insulin_ secretion

Question 34

**B₁** Receptor Activation Effects

Answer 34

_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**)

Question 35

**B₂** Receptor Activation Effects

Answer 35

_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**)

Question 36

What is the **general effect** of **B2 receptor activation**?

Answer 36

**RELAXATION**

Question 37

**D₁** **(Peripheral)** Receptor Activation Effects

Answer 37

_Renal, Mesenteric, Coronary **Vasculature**_ --\> **Vaso**_DILATION_**** which leads to **INCREASED** _GFR, RBF & Na+ excretion_ \*\*\*Treats **URINARY RETENTION**\*\*\*

Question 38

How does **atropine** effect the **M3** **receptors** of the **Eye**?

Answer 38

**INHIBITS** them, leading to **_Dilation_** and **no response to PEN LIGHT**