During a cardiovascular examination,a patient has a resting heart rate of 65 beats/minute and a blood pressure of 100/70 mm Hg in the supine position.In the upright position at steady state,the patient's heart rate is 74 beats/minute,and the blood pressure is 105/70 mm Hg.One physiological change that occurred in the patient as a result of assuming an upright position is:
During a cardiovascular examination,a patient has a resting heart rate of 65 beats/minute and a blood pressure of 100/70 mm Hg in the supine position.In the upright position at steady state,the patient's heart rate is 74 beats/minute,and the blood pressure is 105/70 mm Hg. Agents that increase intracellular cyclic adenosine monophosphate (cAMP),such as β-adrenergic agonists,have a potent vasodilator effect by:
A)Increasing nitric oxide production in smooth muscle. B)Stimulating guanylate cyclase activity in endothelial cells. C)Reducing myosin light-chain kinase (MLCK)activity. D)Suppressing calcium entry into smooth muscle cells. E)Reducing the synthesis of guanosine monophosphate (cGMP)in smooth muscle
The myogenic mechanism for autoregulation of vascular smooth muscle tone:
A)Requires the release of nitric oxide from endothelial cells. B)Involves the release of norepinephrine from sympathetic nerve endings. C)Responds to changes in vessel wall transmural pressure. D)Depends on changes in flow through the vessel. E)Arises from changes in shear stress in the vessel wall.