Lecture 8: ANS 2

Question 1

5 types of adrenergic receptors

Answer 1

Alpha 1
Alpha 2
Beta 1
Beta 2
Beta 3

Question 2

What is the most common type of alpha receptor?

Answer 2

Alpha 1

Question 3

Alpha 1 receptor

Answer 3

Cause the contraction of smooth muscle (ex. vasculature, bladder sphincter and radial muscles of the eye)

Question 4

Alpha 2 receptor

Answer 4

Less common that alpha one and usually have an inhibitory effect of the cells
(ex. found on presynaptic adrengergic nerve terminals, and on beta cells of pancreatic islets)

Question 5

Beta 1

Answer 5

Involved in metabolic functions such as lipolysis and in all functions of the heart

Question 6

Beta 2

Answer 6

Cause relaxation of smooth muscles of bronchioles and wall of the bladder

Question 7

Beta 3

Answer 7

Involved in metabolic functions such as lipolysis

Question 8

what adrenergic receptor is present in the SA node, AV node, and cardiomyocytes?

Answer 8

Beta 1

Question 9

Activation of beta 1 effects on heart

Answer 9

SA node: increase heart rate
AV node: increase conduction velocity
Cardiac muscle: increase contractility

Question 10

General Beta adrenergic receptor mechanism of action

Answer 10

• Beta receptor activated by epinephrine
• Activation f adenylate cyclase
• If b1: stimulation of metabolism, cardiac
• If b2: inhibition and relaxation of smooth muscle in respiratory passageways and in blood vessels of skeletal muscles

Question 11

Beta 1 mechanism of action

Answer 11

1. Protein kinase A stimulates an increase in Ca ions influx to target cells leading to:
   - increase in heart rate
   - Increase in gland secretion
   - Increase in renin secretion by kidney
2. Protein kinase A also stimulates production of hormone sensitive HSL in adipose tissue. HSL catalyzes hydrolysis of triglycerides into free fatty acids and glycerol

Question 12

Beta 3 mediates the lipolysis via

Answer 12

stimulation of adenylate cyclase

B1 receptor antagonists do not block this response

Question 13

Where are B2 receptors found?

Answer 13

Vascular smooth muscle of coronary vessels, walls of bladder, and bronchioles

Question 14

Beta 2 mechanism of action

Answer 14

1. Protein kinase A inhibits myosin light chain kinase which inhibits myosin phosphorylation = relaxation of smooth muscle

Question 15

Alpha adrenergic receptor mechanism of action

Answer 15

-Norepinephrine binds

A1:

• Second messengers activated
• Release of ca from endoplasmic reticulum
  1. Smooth muscle contraction
  2. Gland secretion

A2:

• Reduction in cAMP levels
• Inhibition of cell