NOTES: CONDUCTION AND BLOOD VESSELS

1. What is the location and function of the SA node?  Cardiac conduction system = special cells that create its own nerve impulse  Location: wall of the right atrium  Function: “pacemaker” that causes the atria to contract = heart beat

2. What is the location and function of the AV node?  Location: junction between the atria and ventricles  Function: receives electrical impulse from SA node and causes the ventricle to contract

The heart in action:

3. What is the location and function of the AV bundle?  Location: between the ventricles  Function: the electrical connection between the atria and ventricles

4. What is the location and function of the Perkinje fibers?  Location: bottom of the ventricles  Function: conduction of signals to the ventricular muscles

5. What is a EKG/ECG? What is its function?  Electro- cardiogram  A graphical tracing of the hearts electrical activity

6. EKG Explanation  There are 5 major deflections on an EKG: P, Q, R, S, and T

6. EKG Explanation  P Wave: atria contract

6. EKG Explanation  QRS Complex: ventricles contract and the atria relax during this time

6. EKG Explanation  T wave: ventricles relax and aortic and pulmonary valves close.

7. 5 general classes of blood vessles  Arteries: carry blood away from heart  Arterioles: smallest branches  Capillaries: connect arteries and veins, site of gas exchange  Venules: smallest branches  Veins: carry blood towards the heart

8. Arteries!  Carry blood away from the heart.  Main artery called the aorta  Tough on the outside  Smooth on the inside  Elastic walls of smooth muscle to withstand blood pressure

9. Capillaries  Connect arterioles and venules  Very thin  Only one cell thick  Site of gas exchange  O2 and nutrients from capillaries diffuses across the membrane into the tissues  CO2 and other wastes diffuses into the capillaries

10. Veins!  Carry blood back to heart  Transport waste and un-O2 blood back to heart and lungs  Valves located inside to allow blood to move in one directions

11. Pulmonary circulation  Circulation from heart to the lungs and back to heart

12. Systemic circulation  Circulation from heart to the rest of the body