Receptors

Question 1

H (1,2,3,4) Receptors

Answer 1

Histamine is the endogenous ligand

Effects:
 H1
Systemic vasodialation
bronchoconstriction
ileum contraction
itching

H2
speed up sinus rhythm
gastric acid secretion
smooth muscle relaxation

H3 Neurotransmitter release in CNS

H4 mediate mast cell chemotaxis

Question 2

Beta 1 Receptors

Answer 2

• Increase cardiac output by increasing heart rate, conduction velocity, and stroke volume (by enhancing contractility).
• Increase renin secretion
• Increase ghrelin secretion from the stomach.[11]

Question 3

B 2 Receptors

Answer 3

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Question 4

Andrenergic Receptor

Answer 4

The adrenergic receptors (or adrenoceptors) are a class of G protein-coupled receptors that are targets of the catecholamines, especially norepinephrine (noradrenaline) and epinephrine (adrenaline).

Many cells possess these receptors, and the binding of a catecholamine to the receptor will generally stimulate the sympathetic nervous system.

Question 5

Sympathetic nervous system

Answer 5

Fight or Flight response
which includes widening the pupils of the eye, mobilizing energy, and diverting blood flow from non-essential organs to skeletal muscle.

Question 6

Adregenergic Receptors A1

Answer 6

vasoconstriction

smooth muscle contraction

Question 7

Adregenergic Receptors A2

Answer 7

Inhibition of transmitter release

Smooth muscle contraction

Question 8

Adregenergic Receptors B

Answer 8

vasodialation

Heart muscle contraction, smooth muscle relaxation, glycogenolysis

Question 9

Beta 1 receptors - heart muscle contraction
Beta 2 receptors - smooth muscle relaxation - bronchodilator

Alpha 1 receptors - smooth muscle contraction
Alpha 2 receptors - smooth muscle contraction and neurotransmitter inhibition

Beta-1 vs Beta-2 receptor location
“You have 1 heart and 2 lungs”
Beta-1 are therefore primarily on heart
Beta-2 primarily on lungs

Answer 9

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