ANS

Question 1

Organization of nervous system

Answer 1

Question 2

ion channel receptor

Answer 2

• either open or closed
• a closed channel prevents ions from flowing along a concentration gradient
• an open channel allows ions to flow along a concentration gradient

Example: voltage gated Na+ channel

Question 3

G Protein Coupled Receptor

Answer 3

Works in 1 of 2 ways:
- Opens/closes ion channel (Ex: Musc. 2 receptor in SA node)
- Activates or inhibits an enzyme inside a cell (A1 receptor in vascular smooth muscle- picture)

Question 4

Enzyme-linked receptor

Answer 4

• receptor is also an enzyme
• at rest, catalytic domain inactive
• signal binds, catalytic domain activated

Ex: insulin receptor in skeletal muscle (linked to enzyme tyrosine kinase)

Question 5

Intracellular receptor

Answer 5

• located in cytoplasm or nucleoplasm
• signal diffuses through cell membrane and binds to receptor inside cell

Ex: steroid binds to receptor in cystoplasm; thyroid hormone binds to receptor in nucleus

Question 6

GPCR Signal Transduction

Answer 6

Question 7

Receptors:
* A1
* M1, 3, 5
* V1
* H1

Answer 7

• Signal transduction: Gq
• Effector: stimulates Phospholipase C
• 2nd mess: increase IP3, DAG, Ca+

Question 8

Receptors:
* A2
* M2, 4
* D2

Answer 8

• Signal transduction: Gi
• Effector: inhibit adenylate cycle
• 2nd mess: decrease cAMP

Question 9

Receptors:
* B1, B2, B3
* D1
* V2
* H2

Answer 9

• Signal transduction: Gs
• Effector: stimulates adenylate cyclase
• 2nd mess: increase cAMP

Question 10

B1 (sympathetic)

Answer 10

Effects:
Heart
* + inoptropy
* + chronotropy
* + dromotropy

Question 11

B2 (sympathethetic)

Answer 11

Effects:

Lung
*Bronchodilation

Urinary tract
* Bladder sphincter contraction
* Increase renin secretion

Skeletal muscle
* Vasodilation

Question 12

A1 (sympathetic)

Answer 12

GI tract:
*Vasoconstriction sphincter contraction

Glands:
* Sweating
* Decrease pancreatic activity

Urinary Tract
* Bladder sphincter contraction
* Increase renin secretion

Skin
* Vasoconstriction

Pupils
* Dilation (mydriasis)

Question 13

M1 (Parasympathetic)

Answer 13

Glands-
Increased:
* Salivation
* Lacrimation
* Pancreatic activity

Question 14

M2 (Parasympathetic)

Answer 14

Heart
* - inotropy
* - chronotropy
* - dromotropy

Question 15

M3 (Parasympathetic)

Answer 15

Lungs
* Bronchoconstriction
* Increased gland secretions

GI
* Increase motility
* Sphincter relaxation
* Increase gland secretion

Glands
Increased:
* Salivation
* Lacrimation
* Pancreatic activity

Urinary Tract
* Bladder sphincter relaxation

Pupils
* Constriction (miosis)

Question 16

ANS influence on eye

Answer 16

• SNS > A1 stimulation > radial (dilator pupillae) muscle contraction > mydriasis (pupil dilation)
• PSNS > Muscarinic stimulation > sphincter pupillae muscle contraction > miosis (pipil constriction)

Question 17

Stimulation of alpha-2 receptors reduces: (select 2)
A. sympathetic tone
B. shivering
C. serum glucose
D. platelet aggregation

Answer 17

A. sympathetic tone
B. shivering

Also produces sedation, hypnosis, analgesia, depresses LOC, inhibits insulin release > hyperglycemia, promotes platelet aggregation

Question 18

Name three A2 receptor locations

Answer 18

1. Presynaptic: NE releasing neurons in CNS & PNS
2. Postsynaptic: smooth muscle & other tissues/organs
3. Nonsynaptic: Platelets

Question 19

A2 receptor location and effects

Answer 19

Question 20

A2 receptor stimulation & transient HTN

Answer 20

Rapid administration of precedex can produce biphasic BP pressure response:

• stimulation of postsynaptic A2 receptors in PERIPHERAL aterial & venous circulation > acute vasoconstriction 7 HTN
• CNS effects lag behind; once kick in, CENTRAL A2 effect over powers peripheral A2 effects: sedation, MAC reduction, bradycardia, vasodilation (hypotension)