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1. Mod 11: Part II Heart anatomy, blood flow, blood vessels, heartbeat

2. External Anatomy of the Heart: Front View (anterior)

3. External Anatomy of Heart: Back View (posterior)

4. Internal View of Heart (anterior )

5. Videos https:// www.youtube.com/watch?v=xDaR-j2pwuU https:// www.youtube.com/watch?v=X9ZZ6tcxArI

6. Path of Blood Systemic Circulation Left ventricle thru aortic semilunar valve (AV) into Aorta Aorta (largest artery) to smaller arteries then to arterioles Arterioles –capillaries (gas exchange)— venules Venules to veins to Superior/Inferior Vena Cava Superior/Inferior Vena Cava to Right Atrium Pulmonary Circulation Right atrium thru right atrioventricular valve to right ventricle Right ventricle thru pulmonary semilunar valve into pulmonary trunk Pulmonary trunk splits into right and left pulmonary arteries R/L pulmonary arteries to lungs where gas exchange occurs (gets rid of carbon dioxide, picks up more oxygen) Lungs to pulmonary veins Pulmonary veins to left atrium Left atrium thru left atrioventricular valve into left ventricle Left Atrioventricular Valve has 2 more names: Mitral Valve & Bicuspid Valve Right Atrioventricular Valve has one other name: Tricuspid valve

7. General Info about blood vessels A. Three layers 1. Tunica  intima ( intera ) a . Inner most layer b . Endothelium          i . Simple squamous  c. Some larger vessels have  subendothelium          i . Loose connective tissue        ii. Basement membrane 2. Tunica media   a . Middle layer  b. Circularly arranged smooth muscle   c . Chemical and nervous control of degree of contraction          i . Sympathetic NS    d . Change in diameter          i . Vasoconstriction        ii. Vasodilation 3. Tunica  adventitia (externa)   a. Made of collagen fibers   b. Function        i . Protection      ii. Reinforcement     iii. Anchor to surrounding tissue     c . Accessory tissues         i . Nerve fibers       ii. Lymphatic vessels       iii. Elastic network      iv. Tiny blood vessels within layer-vasa  vasorum

8. Blood Vessels Arteries 3 Tunics Tunica intima ( endolithium ) Tunica media Tunica adventitia Capillaries Tunica Intima Only Made of simple squamous epithelium and a basement membrane called endolithium Veins All 3 tunics  Formed from  venules             b. Thinner walls and less muscle than arteries             c. Little muscle in media                          i . Mostly elastin             d. Externa is thickest wall layer B. Capacitance vessels 1. Veins act as reservoirs             a. Large lumens             b. Low blood pressure allows walls to thin 2. Venous valves             a. Prevent backflow             b. Folds of  interna

9. Your Heartbeat http:// my.clevelandclinic.org/health/articles/heart-blood-vessels-heart-beat Lub -sound of atrioventricular valves closing Dub-sound of semilunar valves closing