CHS 370 Cardio CW

2. Blood ______ balances with a need for greater blood flow to working muscles and may be limited during exercise.
4. The pause of the action potential within the heart at the AV bundle (Bundle of His) before passing to the bundle branches allow for atrial _________. It is represented by the P-R interval on an EKG.
6. Training can increase stroke volume and decrease heart rate, leading to greater efficiency and an improved pressure-_______ relationship.
8. Training can reduce the intrinsic firing rate of the ________ node.
10. The greatest control over heart rate during exercise is provided by the _________.
11. Veins serve as reservoirs of blood storing as much as 65% of blood volume at rest. They are _______ vessels.
12. The heart remains depolarized for a fraction of a second in both the atria and ventricles before being rapidly repolarized. The period of depolarization is represented by a _________ which allows for a long, strong isometric contraction to build pressure.
13. EDV – SV = ______. The volume in the ventricles during isovolumetric relaxation.
15. Blood flow through the heart is __________ and the orientation of valves control the flow.
17. As much as 75% of blood is stored in ______, the low pressure collection and return circuit.
18. ______ dominance occurs during exercise, increasing parasympathetic activity and possibly reducing sympathetic activity.
21. Primary purpose of the atria, although they do also act as primer pumps.

1. After the ventricles eject blood, a period of isovolumetric _______ occurs where pressure drops within the ventricles but volume stays the same.
3. Trained individuals may have and increase in myocardial _______ as stroke volume is increased, possibly as much as 20%.
5. Structures that connect myocytes which allow for chemical and electrical coupling.
7. The anticipation of exercise will _______ heart rate and blood flow before activity begins due to cortical input.
9. The best predictor of V02 max (cardiovascular capacity) is cardiac ______ which can be increased as much as 20% with training.
14. During steady-state exercise, a prolonged increase in temperature may exhaust the metabolic systems of the heart causing cardiovascular _______.
16. Period of time when an additional action potential is prevented from restimulating the heart. Required to allow the heart to fill so it can keep pumping.
19. The action potential that spreads through the heart is greater than the resting membrane potential by about 20 mV. The extra voltage is called the _______ potential.
20. After submaximal exercise, _______ blood pressure can be reduced to pre-exercise levels temporarily because total peripheral resistance is low after exercise.