1. Chapter 42: Circulation By Lauren Shevchek and NonyeEnogwe

2. Circulation…. the continuous motion by which blood travels through all parts of the body under the action of the heart • Helps with the transportation of blood throughout the body • Regulates the

3. Different forms of circulatory sytstems… • Closed circularory system • Open circulatory system -Circulatory fluid (blood) -Set of tubes (blood vessels) -Muscular pump (heart) • Gastrovascular cavity

4. Vertebrate Circulatory System • Blood: used to carry dissolved materials and cells • Blood vessels: carries materials and allows for exchange through the body • Heart: muscle that moves blood in a distinct direction

5. Fish Amphibians Mammals Amphibians have a three-chambered heart and two circuits of blood flow: pulmocutaneousand systemic. With double circulation, blood is delivered to systemic organs under high pressure. There is some mixing of oxygen-rich and oxygen-poor blood within the single ventricle. Mammals have a four-chambered heart and double circulation. Inside of the heart, oxygen-rich blood is kept separated from oxygen-poor blood. Fish have a two-chambered heart and a single circuit of blood flow

6. Pulmonary & Systemic • lead to capillaries in the gas-exchange organs • Where most of the returning oxygen-rich blood is pumped into

7. Double Circulation Advantages over single circulation • no mixing of the oxygenated and deoxygenated blood • blood is pumped to the rest of the body with a higher concentration of oxygen

8. Cardiac Cycle  the alternating contractions and relaxations of the heart • Systole • Diatole

9. Cardiac Output Main two factors • Heart rate • Stroke volume

10. Heart Valves

11. Abnormal heart Heart Murmur: an abnormal sound of the heart; sometimes a sign of abnormal function of the heart valves

12. SA Node • As nerves become more sympathetic, heart rate goes up and when it becomes parasympathetic the heart rate goes • Hormones secreted into the blood by glands influence the pacemaker like epinephrine (“fight-or-flight” hormone from the adrenal glands) which increases heart rate • As temperature increases, the rate of the pacemaker also increases and vise versa • Exercise increases heart rate, an adaptation which allows the circulatory system to provide extra oxygen needed by the muscles hard at work a small body of specialized muscle tissue located in the wall of the right atrium of the heart that acts as a pacemaker by producing a contractile signal at regular intervals

13. Structures