1. Bundle of His

3. Atrial systole P wave Ventricular systole QRS wave P Q R S T http://www-medlib.med.utah.edu/kw/pharm/hyper_heart1.html

4. Sinoatrial node (PACEMAKER) Generates electrical impulses that initiate heartbeats. CARDIAC CYCLE: Diastole: Relaxation of atria and ventricles Systole: Contraction of atria and ventricles

5. Circulatory system function Digested food (as glucose) and fuel to cook the food (oxygen) need to be carried to every cell of the body for metabolism.

6. Evolution of the heart

7. Circulatory system Open (Mollusks and arthropods): Hemolymph (blood) flows through a system of channels and cavities. Closed (from annelids on): Circulating fluid always enclosed within vessels that transport blood to and from a pump (heart).

8. Open vs Closed

9. Circuits Pulmonary: Circulation between heart and lungs. Systemic: Circulation between heart and rest of body.

10. ventricle Tricuspid valve Semilunar valve

11. ventricle Tricuspid valve Semilunar valve

12. Blood vessels Arteries: Blood leaving heart. Branch out to arterioles and then capillaries. Veins: Blood returning to heart. After gas exchange, blood is collected in venules leading to veins. Check your homework after reading this slide!

13. Arteries comprised of 3 layers and made up of elastic fibers. Fat in aorta acts as shock absorber.

14. Composition of blood PLASMA: extracellular environment (proteins, ions, hormones, etc.) BLOOD CELLS Erythrocytes (RBC): Oxygen transport Leukocytes (WBC): Immunological defense Platelets: Blood clotting

15. Erythocytes = red; platelets = yellow; T-lymphocyte = light green (SEM x 9,900). Copyright Dennis Kunkel, www.DennisKunkel.com