Question

a. How will adding a warm solution to the heart effect heart rate and contraction and state the physiological reasoning behind this.

b. How will adding epinephrine to the heart effect heart rate and contraction and state the physiological reasoning behind this.

c. How will cooling the heart down effect heart rate and contraction and state the physiological reasoning behind this.

d. How will adding an epinephrine agonist effect the heart and predict the effect it will have on the heart and state your

reasoning.

Answer 1

a) Adding warm solutions to heart leads to Increased heart rate and contraction. As adding warm solution leads to vasodilation of the blood vessel and leading to more heat loss. increased temperature is sensed by thermoregulatory system and activate sympthetic outflow and it leads to increased heart rate.

b) Addinng epinephrine will inrease the heart rate and contraction. As heart has beta-1 adrnergic receptors to which epinephrine binds and leads to increased heart rate and contraction.

c) Cooling the heart down leads to decrease in heart rate and contraction. This occurs due to vasoconstriction caused by decrased temperature leading to decrease in heat loss. This Decreased temperature sensed by thermoregulatory system and it increases parasympathetic outflow and hence decreasing heart rate and contraction.

d) epinephrine agonist has similar effect as epinephrine i.e. leading to increased heart rate and contraction. Epinephrine agonist act directly on Beta-1 receptor on heart and leads to increased heart rate and contraction.