Cardiovascular System PDF

Cardiovascular system  cardiovascular system delivers blood-vascular, or simply the oxygen, nutrients, hormones, circulatory, system and other important Heart-a muscular pumping device, a substances to cells and organs closed system of vessels called in the body...

Cardiovascular system  cardiovascular system delivers blood-vascular, or simply the oxygen, nutrients, hormones, circulatory, system and other important Heart-a muscular pumping device, a substances to cells and organs closed system of vessels called in the body. It plays an arteries, veins, and capillaries. important role in helping the body meet the demands of activity, exercise, and stress. functions- transportation, protection, fluid balance and thermoregulation.  The heart is a hollow, muscular organ situated in the space between lungs in he thoracic cavity It lies obliquely, little more to the left that the right Apex is about 9cm to the left About the size of a clenched fist Composed pf endocardium, myocardium and pericardium  Endocardium – the inner layer and it consists of endothelial tissue that lines the inner surface of the heart and the cardiac valves Myocardium – the middle layer and composed of muscle fibers that enable the heart to pump Epicardium-outer layer, tightly adherent to the heart ad the base of the great vessels Pericardium-thin, fibrous, double layered sac that surrounds the heart The heart is consist of 4 chambers Right atrium Left atrium Right ventricle Left ventricle  Right atrium ✓ Quadrilateral in shape ✓ Receives deoxygenated blood from the superior and inferior vena cava and the coronary sinus ✓ Interiorly, the atrium is divided into anterior rough part called atrium proper and posterior smooth aorta called sinus venosus ✓ It is separated from the right ventricles by the tricuspid valve and from the left ventricle by the tricuspid valve and from the left atrium by the interatrial septum  Right ventricle It is a triangular chamber situated to left and right atrium which receives blood from right atrium and pumps blood into the pulmonary trunk The interior is rough due to muscular rings called as trabeculae carnae It contains cords connecting cusps of valves and the papillary muscles known as cordae tendanae It is separated from the right atrium and left ventricle by tricuspid calve ad interventricular septum respectively Heart valves The cardiac valves are composed of fibrous tissue and allow blood to flow in one direction they prevent regurgitation of the blood The valves open and close as a result of blood flow and pressure differences there are 2 pairs of valves in the heart A pair of atrioventricular valves The tricuspid and mitral valves are known as the atrioventricular A pair of semilunar valves valve because they are located between the atria and the ventricles The pulmonic and aortic valves are known as the semilunar valves because each has three leaflets shaped like half-moons AV Valves Semilunar Valves Description Atrioventricular valves are present between the arteries Semilunar valves are present between the ventricles and and ventricles. major heart arteries. Flow of Blood It allows the flow of blood from the right atrium to the It allows the flow of blood from the left ventricle to the right ventricle and the left atrium to the left ventricle. aorta and the right ventricle to the pulmonary artery. Sound of the Heart The closure of the valves makes the first sound of the The closure of the valves makes the second sound of the cardiac cycle, “LUBB” cardiac cycle, “DUB” Valves The two valves are the tricuspid and mitral valves. The two valves are aortic and pulmonary valves. Special Feature The AV valves are attached to connective tissue chordae No such tissue is found. tendineae that prevents the valves from inverting.  Circulation of the blood The blood supply throughout the body including the heart, lungs and Pulmonary circulation. This part of the cycle other body organs and tissue is carries oxygen-depleted blood away from the called circulation of blood heart, to the lungs, and back to the heart. Systemic circulation. This is the part that 3 types carries oxygenated blood away from the heart and to other parts of the body. Systemic/ general Coronary circulation. This type of circulation provides the heart with oxygenated blood so it can Pulmonary function properly Coronary  Superior vena cava 7 Capillaries of head and Returns deoxygenated blood from Forelimbs - EXCHANGE body to heart RA Pulmonary artery Pulmonary artery Carries deoxygenated blood to lungs Capillaries Aorta 9 Capillaries of right Lung GAS EXCHANGE of left Lung GAS EXCHANGE 3 2 3 4 11 Pulmonary vein Pulmonary vein Carries oxygenated blood 5 to heart: LA 1 Right Atrium Left Atrium - LA RA - Receives deoxygenated blood 10 Receives oxygenated blood from body from lungs Right Ventricle Left Ventricle - LV RV - Pumps blood to lungs Pumps oxygenated blood to body Inferior vena cava Aorta = main artery to body Returns deoxygenated blood from for Systemic Circulation body to heart RA mammalian 8 Capillaries of abdominal organs and hind limbs cardiovascular system EXCHANGE with body cells Coronary circulation is the circulation of blood in the arteries and veins that supply the heart muscle (myocardium). Coronary arteries supply oxygenated blood to the heart muscle. Cardiac veins then drain away the blood after it has been deoxygenated. Because the rest of the body, and most especially the brain, needs a steady supply of oxygenated blood that is free of all but the slightest interruptions, the heart is required to function continuously. 5 types of blood vessels Circulatory systems link exchange surfaces with cells throughout the body In small and/or thin animals, cells can exchange materials directly with the surrounding medium. In most animals, transport systems connect the organs of exchange with the body cells. Most complex animals have internal transport systems that circulate fluid.  Gastrovascular Cavities Simple animals, such as cnidarians, have a body wall that is only two cells thick and that encloses a gastrovascular cavity. This cavity functions in both digestion and distribution of substances throughout the body. Some cnidarians, such as jellies, have elaborate gastrovascular cavities. Flatworms have a gastrovascular cavity and a large surface area to volume ratio.  Internal transport in gastrovascular cavities Circular canal Mouth Pharynx Mouth Radial canal 5 cm 2 mm (a) The moon jelly Aurelia, a cnidarian (b) The planarian Dugesia, a flatworm  Open and Closed Circulatory Systems In insects, other arthropods, and most More complex animals have molluscs, blood bathes the organs directly in an open circulatory system. either open or closed In an open circulatory system, there is no circulatory systems. distinction between blood and interstitial fluid, and this general body fluid is more Both systems have three basic correctly called hemolymph. components: A circulatory fluid = blood or In a closed circulatory system, the hemolymph. blood is confined to vessels and is distinct A set of tubes = blood vessels. from the interstitial fluid. A muscular pump = the heart. Closed systems are more efficient at transporting circulatory fluids to tissues and cells.  Open and closed circulatory systems Heart Heart Blood Hemolymph in sinuses Interstitial Small branch vessels surrounding organs fluid In each organ Pores Dorsal vessel (main heart) Tubular heart Auxiliary hearts Ventral vessels (a) An open circulatory system (b) A closed circulatory system  Organization of Vertebrate Closed Circulatory Systems Humans and other vertebrates have a closed circulatory system, often called the cardiovascular system. The three main types of blood vessels are: arteries - away from the heart. veins - toward the heart. capillaries - exchange with body cells.  Arteries branch into arterioles and carry blood to capillaries. Networks of capillaries called capillary beds are the sites of chemical exchange between the blood and interstitial fluid. Venules converge into veins and return blood from capillaries to the heart.  Vertebrate hearts contain two or more chambers. Blood enters through an atrium and is pumped out through a ventricle. Atria - receive blood Ventricles - pump blood  Single Circulation Bony fishes, rays, and sharks have single circulation with a two-chambered heart. In single circulation, blood leaving the heart passes through two capillary beds before returning. Single Gill capillaries circulation in fishes Artery Gill circulation Ventricle Heart Atrium Systemic Vein circulation Systemic capillaries  Double Circulation Amphibian, reptiles, and mammals have double circulation. Oxygen-poor and oxygen-rich blood are pumped separately from the right and left sides of the heart. Mammals and Amphibians Reptiles Birds Lung and skin capillaries Lung capillaries Lung capillaries Pulmocutaneous Right Pulmonary Pulmonary circuit systemic circuit circuit aorta Atrium (A) Atrium (A) A A A A Ventricle (V) V V Left V V Right Left Right Left systemic Right Left Systemic aorta Systemic circuit circuit Systemic capillaries Systemic capillaries Systemic capillaries  In reptiles and mammals, oxygen-poor blood flows through the pulmonary circuit to pick up oxygen through the lungs. In amphibians, oxygen-poor blood flows through a pulmocutaneous circuit to pick up oxygen through the lungs and skin. Oxygen-rich blood delivers oxygen through the systemic circuit. Double circulation maintains higher blood pressure in the organs than does single circulation.  Adaptations of Double Circulatory Systems Amphibians: Turtles, snakes, and lizards have a Frogs / amphibians have a three- three-chambered heart: two atria chambered heart: 2 atria and 1 and one ventricle. ventricle. In alligators, caimans, and other The ventricle pumps blood into a crocodilians a septum - partially forked artery that splits the or fully divides the ventricle. ventricle’s output into the pulmocutaneous circuit and the Reptiles have double circulation, systemic circuit. with a pulmonary circuit - lungs Underwater, blood flow to the and a systemic circuit. lungs is nearly shut off. Mammals and birds have a four-chambered heart with two atria and two ventricles. The left side of the heart pumps and receives only oxygen-rich blood, while the right side receives and pumps only oxygen-poor blood. Mammals and birds are endotherms and require more O2 than ectotherms.