Cardio - case study 13

Question 1

What is the primary goal of cardiovascular responses to exercise?

Answer 1

increase O2 delivery to tissues

Question 2

Venoconstriction has what overall effect?

Answer 2

increased venous return to the heart. A1 receptors are stimulated during exercise to induce arteriolar and venoconstriction

Question 3

What metabolites induce vasodilation? of what arterioles?

Answer 3

nitric oxide, adenosine, lactate, K+ - produce vasodilation of skeletal muscle arterioles

Question 4

What effect on TPR does local vasodilation produce?

Answer 4

decrease in overall TPR

Question 5

Where do local responses dominate?

Answer 5

myocardium - controlled by adenosine and decreased PO2

Question 6

Pulse pressure =

Answer 6

systolic pressure - diastolic pressure

Question 7

Why does pulse pressure increase during exercise?

Answer 7

because stroke volume increased, which increased arterial pressure (difference between systolic and diastolic volume)

Question 8

Why is diastolic volume decreased?

Answer 8

because TPR is decreased due to local factors producing vasodilation

Question 9

Why would propranolol decrease exercise tolerance?

Answer 9

propranolol is a beta 1 antagonist - beta 1 receptor stimulation is responsible for the increase in cardiac output for increased O2 to tissues

Question 10

What mechanisms are responsible for changes in skin tone and temperature?

Answer 10

early in exercise, blood is shunted away due to cutaneous sympathetic stimulation. As more O2 is consumed during exercise, vasodilation occurs and blood is shunted to skin surface