Cardiovascular System: Intrinsic Conduction System
1. autorhythmic cardiac, impulses (action potentials)
2. heart depolarization
3. a. initiates the depolarizing impulse and sets the pace for the entire heart
b. link between the SA node and the AV node
c. delay occurs allowing atria to contract
d. link between atria and ventricles
e. convey impulses down the interventricular septum
f. convey the depolarizations throughout the ventricular walls
4. contractile
5. ECG—electrocardiogram (or EKG)
6. a. atrial depolarization
b. ventricular depolarization
c. ventricular repolarization
7. QRS complex
8. atrial, contraction
9. QRS complex
10. tachycardia
Cardiovascular System: Cardiac Action Potential
1. Through gap junctions
2. contract
3. 1. sodium, into
2. potassium, out of
3. fast calcium, into
4. positive
5. decreased, potassium, sodium
6. –40, fast calcium channels
7. potassium, repolarization
8. Na+-K+ ATPase
9. Sarcoplasmic reticulum
10. Sodium, calcium, and potassium
11. a. fast sodium channels
b. slow calcium channels
c. potassium channels
12. Sodium channels
13. Calcium channels
Cardiovascular System: Cardiac Cycle
1. differences in blood pressure
2.
Chamber
Valve
Chamber/Vessel
Right ventricle
Pulmonary semilunar
Pulmonary trunk
Left ventricle
Aortic semilunar
Semilunar aorta
Left atrium
Mitral
Left ventricle
Right atrium
Tricuspid
Right ventricle
3. a. mid to late, diastole
b. atrioventricular, AV
4. Intraventricular pressure is greater than atrial pressure.
5. Intraventricular pressure is greater than pressure in the pulmonary trunk and aorta.
6. Blood flow back toward the heart (due to aortic pressure being greater than intraventricular
pressure).
7. Atrial pressure is greater than intraventricular pressure.
8. With hypertension, the ventricular pressure must rise higher to open the semilunar valves.
For the same increase in pressure in a normotensive person, less blood is ejected in a
hypertensive person. Thus, the heart of someone with hypertension must work harder to
eject the same stroke volume.
9. 70
10.
Phase
AV Valves
Semilunar Valves
Ventricular filling
Open
Closed
Isovolumetric
Closed
Closed
Ventricular ejection
Closed
Open
Isovolumetric
Closed
Closed
contraction
relaxation
Cardiovascular System: Cardiac Output
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
The amount of blood pumped out by each ventricle in one minute
CO = HR  SV
The amount of blood ejected from each ventricle in one heartbeat
SV = EDV – ESV
a. 75 beats/minute (bpm)
b. 70 ml/beat
c. 120 ml
d. 50 ml
CO = HR  SV
= 75 beats/minute x 70 ml/beat
= 5250 ml/minute or 5.25 L/minute
HR SV CO
a.  SNS



b.  Venous return



c. Exercise



d.  Calcium



e.  HR



An increase in contractility leads to an increase in the force of contraction.
An increase in filling time leads to an increase in end diastolic volume (Frank Starling
mechanism).
3 bottles (6 liters)