2. Heart Double Pump: Rt side is pulmonary circulation, left side is systemic circulation. Pulmonary circulation – blood in the right side of heart, pulmonary vessels, and lungs. Systemic circulation – blood in the left side of heart and the rest of the body. Heart is the size of your fist. Located between lungs within the mediastinum, apex found in the 5 th intercostal space, approx. 9 cm of midline. Round point is called apex, this is what you see beating. Flat portion is called base, it lies on diaphragm. Pericardial sac: closed sac that surrounds heart and anchors to the mediastinum.

3. Cardiovascular System

4. External Features of Heart Left and right coronary artery, feeds the heart with blood. Left and Right pulmonary artery, feeds the lungs with deoxygenated blood from RV. Left and Right pulmonary vein, feeds the LA with oxygenated blood from lungs. Aorta: ascending, transverse, and descending. Superior and Inferior Vena Cava Apex Base

6. Internal Features of Heart Right Atrium Tricuspid Valve Right Ventricle Left Atrium Mitral Valve (Bicuspid) Left Ventricle Papillary Muscles Chordae Tendinae Aortic and Pulmonary Semi-lunar valve.

7. Heart Composed of myocardial muscle. Heart is autorhythmic, it beats automatically and rhythmically. If taken out of body, it can continue to beat under proper circumstances. SA node is the pacemaker of the heart. It signals the contraction of the atria, which in turn signal the AV node to send impulse to cause ventricles to contract. Heart sounds: first sound- Lubb, closing of tricuspid and bicuspid valves. Second sound- Dupp, closing of semilunar valves

8. Arteries and Veins Arteries lead away from the heart. Always carry oxygenated blood. Exception is Pulmonary artery, which flows away from heart to lungs with deoxygenated blood. Arteries are very elastic in order to expand to hold up to high pressure. Veins lead to heart. Always carry deoxygenated blood. Exception is Pulmonary vein, which flows toward heart from lungs with oxygenated blood. Veins are non-elastic, don’t need to expand for pressure. Contain valves to prevent backflow, moves passively by surrounding muscle contractions.

9. Adventicia: (Tunica Extera), glues blood vessels to surrounding areas. Media: mostly smooth muscle, some connective tissue. Intima: endothelium

11. Vessels and blood flow Artery, arteriole, capillary, venule, vein. Connective tissue in the arteries is elastic connective tissue. Smooth muscle provides a smooth steady flow at end of arterioles, even though at beginning its pulsatory. Velocity of flow is inversely related to the cross sectional area, smaller vessel = faster flow, wider vessel = slower flow. Total cross section is what counts, smallest in aorta, largest in capillaries.

12. Vessels and blood Total blood volume is about 5 liters. Broken into pulmonary and systemic systems. Pulmonary: blood flow from Rt. Ventricle to lungs and back to Lt. Atrium Systemic: blood flow from Lt. Ventricle to tissues of body and back to heart. 15% is in systemic arteries.

13. Arterioles Terminal arteries, last of the arteries on the branching tree. Very little elastic tissue, with more smooth muscle to adjust size of vessel, adjustable vessel allows us to have adjustable flow. Like faucets on a sink. Vasoconstriction: decreasing diameter of vessel Vasodilation: increasing diameter of vessel. Must be about 20 thick before you can see Pre-capillary sphincter are faucets that control flow into capillary bed.

14. Capillaries Site of gas and waste exchange. Very small, cells go through one at a time. No connective tissue or smooth muscle. Consists of a single layer of endothelium. Very permeable Dissolved materials in blood that is smaller than proteins can leak out from cracks of capillary into ISF because of pressure difference.

15. Blood flow back into venuoles Arteriole end has high pressure inside of vessel, ISF is low pressure, results in blood flow out. Venuole end of capillary, there is higher pressure in ISF and wants to flow back into low pressure venuole.

16. Veins Have thinner walls with more smooth muscle which allows for alteration of diameter of veins. Valves run all along length of veins Vein wall thickened at place of valve. Valves are needed for unidirectional flow. Veins have low pressure, high volume. 50% of blood in veins at all times. Venous side is a reservoir for blood.

17. Veins Contraction of smooth muscle leads to high venous return and an increased cardiac output. “Venous Pumps” concept, not real pumps 1. Passive constriction of veins by skeletal muscle. 2. Arterial pulses 3. Valves

18. EKG- electrocardiograph A normal EKG consists of a P wave, a QRS complex, and a T wave. P wave is the result of A.P. that cause depolarization of atria, it signals the onset of atrial contraction.

19. EKG (QRS Complex) The QRS complex is composed of three individual waves, the Q, R, and S waves. The QRS complex results from ventricular depolarization and signal the onset of ventricular contraction.

20. EKG (T wave) T wave represents the repolarization and precedes ventricular relaxation. A wave of repolarization of atria cannot be seen because it happens during QRS complex.

24. Major cardiac disorders Tachycardia- heart rate in excess of 100 beats per minute. Ventricular Tachycardia (Asystole)- frequently causes fibrillation. Heart vibrates uncontrollably. Brachycardia- Heart rate less than 60 beats per minute. SA Node Block- Cessation of P wave, low heart rate due to AV node acting as pacemaker. Myocardial Infarction (Heart Attack)- section of heart does not receive blood, usually coronary artery is blocked. Usually caused by a thrombus. Stroke – lack of blood to the brain, either caused by an embolus, clot in vessel, or a hemorrhage, a burst vessel, in brain.