NBEO: Boards: General Physiology

Question 1

Membrane Receptors: Adrenoreceptors

1. Alpha 1: What do they do?
   a. Location?
2. Alpha 2: Does what?
   a. Location?
3. Beta 1: Does what?
   a. Location? (SHAK)
4. Beta 2: Does what?
   a. Location?

Answer 1

1. Increase [IP3] –> increased Intracellular [Ca2+]
   a. RADIAL MUSCLE of the IRIS, Vascular Smooth Muscle, and GI Tract (Sphincters)
2. Inhibit Adenylyl Cyclase –> Decreases cAMP.
   a. Presynaptic Adrenergic neurons; Walls of GI tract
3. Stimulates Adenylyl Cyclase –> Increased cAMP
   a. Salivary Glands, HEART, Adipose Tissue, Kidneys
4. Stimulates Adenylyl Cyclase —> Increased cAMP
   a. BRONCHIOLES, GI Tract, Bladder Wall, Vascular Smooth Muscle

Question 2

Cholinergic Receptors

1. Nicotinic
   a. Opens what channels?
   b. Locations?
2. Muscarinic
   a. What does it do?
   b. Location?

Answer 2

1. a. Na+ and K+ channels –> Depolarization **ONLY receptors to open K+ and Na+ Channels. Other receptors alter Ca2+ concentration or cAMP.
   b. Motor End Plates of Skeletal Muscles, Postganglionic Neurons of SNS and PNS, and Adrenal Medulla.
2. a. Increases [IP3} –> increased intracellular [Ca2+]
   b. Vascular smooth muscle, sweat glands, and PNS effector organs.