Both controls can be seen in this lab. Intrinsic controls are within the heart while extrinsic controls are external to the heart (book). The nodal system is one intrinsic control example that has an effect on the heart's pumping activity. The nodal system occurs when the pacemaker places a depolarization rate on the rest of the heart (book). The pacemaker in a frog heart is positioned in the sinus venous, which is an enlarged area between the right atrium and the vena cava (pdf). If the impulse from the depolarization does not reach the ventricle(s) then the heart will beat at a much slower rate than what it usually beats at. The rate can be modified by extrinsic factors such as chemicals, hormones, ions, and metabolites (book). The chemicals and agents used in this lab to modify the frog's heart rate and contraction are extrinsic factors. They are cold water, warm water, pilocarpine, histamine, epinephrine, calcium chloride, sodium chloride, hydrochloric acid, and potassium
Both controls can be seen in this lab. Intrinsic controls are within the heart while extrinsic controls are external to the heart (book). The nodal system is one intrinsic control example that has an effect on the heart's pumping activity. The nodal system occurs when the pacemaker places a depolarization rate on the rest of the heart (book). The pacemaker in a frog heart is positioned in the sinus venous, which is an enlarged area between the right atrium and the vena cava (pdf). If the impulse from the depolarization does not reach the ventricle(s) then the heart will beat at a much slower rate than what it usually beats at. The rate can be modified by extrinsic factors such as chemicals, hormones, ions, and metabolites (book). The chemicals and agents used in this lab to modify the frog's heart rate and contraction are extrinsic factors. They are cold water, warm water, pilocarpine, histamine, epinephrine, calcium chloride, sodium chloride, hydrochloric acid, and potassium