1. Which of the following statements about the adrenergicreceptors is TRUE? Select one:
a. Alpha 1, alpha 2, and beta 1 receptors have greater affinity(or sensitivity) to norepinephrine than epinephrine.
b. Beta 2 receptor has an equal affinity for norepinephrine andepinephrine while beta 3 receptor has a greater affinity forepinephrine than norepinephrine.
c. Beta 1, beta 2, and beta 3 receptors increase cAMP but onlybeta 1 receptor causes an excitatory response in the heartmuscle.
d. Alpha 1receptor activates cAMP and causes an excitatoryresponse to most of the sympathetic target tissues.
e. Alpha 2 activates cAMP and causes an inhibitory response inthe gastrointestinal tract.
2. Which line of defense mechanisms against acid-basedisturbances will be the quickest to maintain blood pH?
a. Buffered by bicarbonate in the blood
b. Respiratory compensation by expiration of carbon dioxide
c. Renal compensation by tubular reabsorption of bicarbonate andtubular secretion of H+
3. Which of the following is TRUE about the signal transductionfor cyclic AMP (cAMP)?
a. Beta 1, Beta 2, and Beta 3 increases cAMP while Alpha 2deactivates cAMP. Â Â
b. Epinephrine and norepinephrine are first messengers that bindequally to Beta 1 receptors to activate adenylyl cyclase in theheart muscle or kidney.
c. Adenylyl cyclase, an amplifier enzyme, converts anintracellular ATP into cAMP, a second messenger.
d. Cyclic AMP (cAMP) activates protein kinase A. Protein kinaseA phosphorylates other proteins that will lead into a cellularresponse.
e. All of the above
f. None of the above
