PowerPoint Presentation: THE CIRCULATORY SYSTEM Part B – Blood Circulatory system Compiled by – Nagaraj Kamble PowerPoint Presentation: Introduction The circulatory system is comprised of the heart, veins, capillaries, arteries, lymph vessels, and lymph glands , which work together to supply the body tissues with nourishment and collect waste materials. PowerPoint Presentation: Anatomy and Physiology of the Heart The heart is a funnel-shaped, hollow, muscular organ that is responsible for pumping blood to all parts of the body. PowerPoint Presentation: Location : The heart is located near the center of the thoracic cavity between the lungs and above the diaphragm. Covering: It is contained in the pericardium (pericardial sac), a double walled membranous covering. It contains fluid called Pericardial fluid which reduces friction during heart beat and protects it from mechanical injuries. Size: In adult about the size of ones fist. Length 12cm, Width 9cm. NOTE: Wrong Notion Heart is on the left side. Fact Contraction of the heart is most powerful at the end and since heart is tilted towards left, it feels as if it is present on left PowerPoint Presentation: The broad end, or base, of the heart is also supported by large arteries and veins . The pointed end, or apex, of the heart is directed toward the abdomen. PowerPoint Presentation: In mammals and birds, the heart is divided into a right and left side and each side is divided into an atrium (upper) and ventricle (lower) . Therefore, the heart is said to have four chambers ( right atrium, right ventricle , left atrium, and left ventricle ). NOTE : atrium = auricle = atria Auricle has thin wall as they receive blood from and pump into the ventricle (Short distance). Ventricle as thick wall because – long distance pumping R. Ventricle upto lungs for oxygenation L.Ventricle to farthest body parts e.g. toe, brain PowerPoint Presentation: NOTE: Heart Attack : Any time if there is a blockage in coronary artery or their branches there is ‘ deadening ’ of corresponding area of heart muscles leading to “ myocardial infarction ” (Common term – Heart attack) Cardiac veins collect blood from heart walls. Regulation of Blood flow by valves: Regulation of Blood flow by valves Total of 4 Valves in heart The atrioventricular valves (AV valve) separate the atrium and ventricle on each side of the heart. The AV valves have flaps of tissues, called leaflets or cusps, which open and close to ensure that the blood flows only in one direction and does not backflow into the atriums. Right auriculo – ventricular valve (atrioventricular valves) The AV valve on the right side of the heart is called the tricuspid valve because it has three leaflets (cusps). The apices of the cord are held by tendinous cords ( Chordae tendinae ) arising from the projections of the ventricle wall known as papillary muscles. Regulation of Blood flow by valves: Regulation of Blood flow by valves 2. Left auriculo – ventricular valve: The AV valve on the left side of the heart is called the bicuspid valve (or mitral valve) because it has two leaflets . 3 Pulmonary semilunar valves: Location: Opening of right ventricle into pulmonary artery. Pocket shaped & 3 in number 4 Aortic semilunar valves: Location: Point of origin of aorta from left ventricle. Pocket shaped & 3 in number bkjbn: bkjbn PowerPoint Presentation: The atrioventricular valves (AV valve) separate the atrium and ventricle on each side of the heart. The AV valves have flaps of tissues, called leaflets or cusps, which open and close to ensure that the blood flows only in one direction and does not backflow into the atriums. PowerPoint Presentation: The AV valve on the right side of the heart is called the tricuspid valve because it has three leaflets (cusps). The AV valve on the left side of the heart is called the bicuspid valve (or mitral valve) because it has two leaflets. PowerPoint Presentation: The pulmonary valve and the aortic valve prevent blood from back-flowing into their respective ventricles . PowerPoint Presentation: The pulmonary valve is located between the right ventricle and the pulmonary artery. The aortic valve is located between the left ventricle and the aortic artery. PowerPoint Presentation: Following the path that the blood takes as it flows through the heart and lungs is the best way to understand the heart’s operation. (This process will be discussed later in the topic of pulmonary circulation.) PowerPoint Presentation: A group of cells called the sinoatrial node (SA node) control the beat of the heart by sending out electrical signals to make the heart pump. PowerPoint Presentation: Anatomy and Physiology of the Vascular System The vascular system is made up of three types of blood vessels : Arteries, Capillaries, and Veins PowerPoint Presentation: Photo from U. S. Federal Government courtesy of Wikipedia. Blood Vessels PowerPoint Presentation: Arteries are blood vessels that carry blood, rich in oxygen, from the heart to other parts of the body. The large arteries have thick walls of elastic-like tissue that enables them to withstand the blood pressure created by the heart’s beating. PowerPoint Presentation: As the arteries extend away from the heart, they branch out into smaller arteries called arterioles . The smaller arteries’ walls are composed of large amounts of smooth muscle instead of the elastic tissue. PowerPoint Presentation: Arterioles branch into smaller vessels called capillaries . At this junction, the arterioles have an especially thick layer of smooth muscle in their walls that carefully controls the amount of blood each capillary receives. PowerPoint Presentation: Blood pressure for the entire circulatory system is maintained by the tension at the end of the arterioles. Shock is a serious condition that occurs when the arterioles dilate (relax) and allow a large volume of blood into the capillary beds. The reduced blood flow that occurs with shock jeopardizes vital organs. PowerPoint Presentation: Capillaries are tiny, thin-walled blood vessels that connect arteries to veins and are located in all body tissues. Capillaries are so small in diameter that blood cells pass through in a single file. PowerPoint Presentation: The semi-permeable membrane of capillary walls allows nutrients , oxygen , and water to diffuse from the blood to the tissues. Waste products, like carbon dioxide , diffuse from the tissues into the blood. PowerPoint Presentation: Capillary Bed Interaction of molecules flowing in and out of blood at a capillary bed. PowerPoint Presentation: Larger tubular connectors, which also connect arterioles to venules, are located within the capillary beds. These tubules allow more blood to flow through an area, help warm tissues, and increase the return of blood pressure to the heart. PowerPoint Presentation: Once blood passes through the capillary beds, it begins its return to the heart. Veins are the blood vessels that return blood to the heart from all parts of the body. PowerPoint Presentation: Capillaries unite to form small veins called venules . The venules join together to form larger veins , which have thin walls and are collapsible. For each artery, there is a much larger vein counterpart. PowerPoint Presentation: Veins have valves that aid the return flow of blood and prevent the blood from reversing flow. These valves allow for muscle contractions and movement of body parts. The valves also assist the return flow of blood to the heart when blood pressure is low. PowerPoint Presentation: Parts of the Circulatory System The total circulatory system is divided into two main parts: Pulmonary circulation, and Systemic circulation. PowerPoint Presentation: Pulmonary Circulation System Red portion of heart and red blood vessels carry oxygen-rich blood. Blue portion of heart and blue blood vessels carry oxygen-poor blood. PowerPoint Presentation: Pulmonary circulation is the part of the circulatory system that takes the blood from the heart to the lungs, where it is oxygenated, and returns it to the heart. The main parts of the pulmonary circulation system include the heart, pulmonary arteries, capillaries of the lungs, and pulmonary veins. PowerPoint Presentation: Blood that is low in oxygen returns to the heart through two large veins called the superior (or cranial) vena cava and the inferior (or caudal) vena cava. The un-oxygenated blood enters the right atrium of the heart. Flow of Blood in Pulmonary Circulation PowerPoint Presentation: The blood then passes through the right atrioventricular ( tricuspid ) valve into the right ventricle. The right ventricle pumps the blood through the pulmonary valve into the pulmonary artery . PowerPoint Presentation: The pulmonary artery quickly divides into two branches. Each branch of the pulmonary artery carries blood to a lung . In the lungs the pulmonary arteries branch into capillaries that surround the alveoli . PowerPoint Presentation: Through diffusion, carbon dioxide moves from the blood into the alveoli and oxygen moves from the alveoli into the blood. The oxygenated blood then returns to the heart through the pulmonary vein into the left atrium . PowerPoint Presentation: From the left atrium , the blood flows through the left atrioventricular ( bicuspid ) valve into the left ventricle . PowerPoint Presentation: The thick-walled left ventricle pumps the blood through the aortic valve into the aorta . The amount of pressure that is required for pulmonary circulation is much less than what is required for systemic circulation. Therefore, the muscle mass developed in the right ventricle is much less that of the left ventricle. PowerPoint Presentation: Un-oxygenated blood is dark or brownish red, while oxygenated blood is bright red. In the pulmonary system, un-oxygenated blood is carried by the pulmonary arteries and oxygenated blood is carried by pulmonary veins. In the systemic system, arteries carry oxygenated blood and veins carry un-oxygenated blood. PowerPoint Presentation: The Systemic Circulation System PowerPoint Presentation: The systemic circulation includes the flow of oxygenated blood from the heart to the tissues in all parts of the body and the return of un-oxygenated blood back to the heart. The blood vessels , including the arteries , capillaries , and veins , are the main parts of systemic circulation. PowerPoint Presentation: Through systemic circulation, oxygen and nutrients are delivered to the body tissues via the arteries. Blood is filtered during systemic circulation by the kidneys (most of the waste) and liver (sugars). PowerPoint Presentation: The systemic circulatory system is complex and its functions vary. The systemic circulatory system is divided into subsystems for particular regions of the body. PowerPoint Presentation: The Flow of Blood Through the Systemic Circulatory System Oxygenated blood leaves the left ventricle of the heart through the aorta , the largest artery in the body. PowerPoint Presentation: The left and right coronary arteries immediately branch from the aorta and carry fresh blood to the heart muscle itself. The coronary veins quickly return that blood back to the heart. PowerPoint Presentation: A heart attack often involves a clot in the coronary arteries or their branches. In this illustration, a clot is shown in the location of #1. Area #2 shows the portion of the damaged heart that is affected by the clot. Image by J. Heuser courtesy of Wikipedia. PowerPoint Presentation: Veins normally accompany arteries and often have similar names. Veins are always larger than the arteries and are sometimes more visible than arteries because they are closer to the skin surface. Most veins eventually empty the un-oxygenated blood into the vena cavas. PowerPoint Presentation: The cranial veins return the blood from the head, neck, forelegs, and part of the thoracic cavity to the right atrium of the heart via the superior vena cava . These cranial veins include the jugular vein , brachial veins , internal thoracic veins , and the vertebral veins . PowerPoint Presentation: The caudal veins return blood from the iliac , lumbar , renal , and adrenal veins to the right atrium of the heart via the inferior vena cava . Before blood is returned to the heart from the stomach, pancreas, small intestine, and spleen, it goes through the liver for filtration. PowerPoint Presentation: This portion of the systemic system is known as the hepatic portal system. The gastric vein (stomach), splenic vein (spleen), pancreatic vein (pancreas), and mesenteric veins (small intestines) empty into the portal vein that carries the blood to the liver. PowerPoint Presentation: In the liver, the portal vein branches into smaller venules and finally into capillary beds. In the capillary beds of the liver, nutrients are exchanged for storage and the blood is purified. The capillaries then join into venules that empty into the hepatic vein , which carries blood to the inferior (caudal) vena cava. PowerPoint Presentation: Anatomy and Physiology of the Lymphatic System The lymphatic system is part of the immune system and acts as a secondary (accessory) circulatory system. PowerPoint Presentation: Functions of the lymphatic system: remove excess fluids from body tissues, absorb fatty acid and transport fat to circulatory system, and produce immune cells (lymphocytes, monocytes, and plasma cells). PowerPoint Presentation: Blood fluid escapes through the thin-walled capillaries into spaces between body tissue cells. Lymph vessels , which have very thin walls, pick up these fluids called lymph . PowerPoint Presentation: Flow of Blood & Lymph Within Tissue PowerPoint Presentation: The lymph vessels join to form larger ducts that pass through lymph nodes (or glands). Each lymph node has a fibrous outer covering (capsule), a cortex, and a medulla. PowerPoint Presentation: Photo from U. S. Federal Government courtesy of Wikipedia. PowerPoint Presentation: Lymph nodes filter foreign substances, such as bacteria and cancer cells, from the lymph before it is re-entered into the blood system through the larger veins. Lymph nodes, which are scattered among the lymph vessels, act as the body’s first defense against infection. PowerPoint Presentation: Lymph nodes produce the following cells: Lymphocytes – a type of white blood cell, Monocytes – a leukocyte that protects against blood-borne pathogens, and Plasma cells – produce antibodies. PowerPoint Presentation: Each lymph node has its own blood supply and venous drainage. The lymph nodes usually have names that are related to their location in the body. PowerPoint Presentation: When a specific location gets infected, the lymph nodes in that area will enlarge to fight the infection . If the lymph node closest to an infected area is unable to eliminate the infection, other lymph nodes in the system will attempt to fight the infection. PowerPoint Presentation: This is particularly critical in the case of cancer , which can be spread from its point of origin to all parts of the body through the lymphatic system. PowerPoint Presentation: Anatomy and Physiology of the Blood Blood is an important component of the circulatory system. Anatomically and functionally, blood is a connective tissue. PowerPoint Presentation: Components of Blood PowerPoint Presentation: Plasma , which makes up 50 – 65% of the total volume of blood, is a straw-colored liquid containing water (90%) and solids (10%). The solids in plasma include inorganic salts and organic substances such as antibodies, hormones, vitamins, enzymes, proteins, and glucose (blood sugar). PowerPoint Presentation: The non-plasma , or cellular, portion of blood is composed of red blood cells, white blood cells, and platelets. Photo from U. S. Federal Government courtesy of Wikipedia. From left to right: Red blood cell (erythrocyte); Platelet (thrombocyte); White blood cell (leukocyte). PowerPoint Presentation: Red blood cells, called erythrocytes , are responsible for carrying oxygen from the lungs to various body tissues. Red blood cells contain hemoglobin, which gives them their characteristic red color and helps them carry the oxygen. PowerPoint Presentation: Red blood cells are biconcave discs, a shape that provides a large area for oxygen exchange. PowerPoint Presentation: Blood platelets, or thrombocytes , are oval-shaped discs that are formed in the bone marrow. Blood platelets help prevent blood loss from injuries to blood vessels by forming clots (white thrombus). PowerPoint Presentation: Platelets may secrete a substance that causes the clot to contract and solidify. Platelets may also secrete a substance that causes an injured vessel to constrict at the injury. PowerPoint Presentation: White blood cells, or leukocytes , are divided into two general categories: Granulocytes, and Agranulocytes. PowerPoint Presentation: Granulocytes are the category of leukocytes that contain granules within the cytoplasm. Granulocytes include: Neutrophils, Eosinophils, and Basophils. PowerPoint Presentation: Agranulocytes are the category of leukocytes that contain very little, if any, granules. Agranulocytes are produced by the lymph nodes, spleen, thymus, and other lymphoid tissue. PowerPoint Presentation: Lymphocytes, and Monocytes. There are two types of agranulocytes: PowerPoint Presentation: Blood clotting is called coagulation and is important in reducing blood loss caused by injury and in healing the injury. PowerPoint Presentation: Fibrin is a thread-like mass produced by fibrinogen (fibrous protein in blood) and thrombin. Fibrin holds the red blood cells, white blood cells, and platelets together to form a blood clot. PowerPoint Presentation: Blood types are classified based on certain antigens and antibodies found on surface of red blood cells. For example, in humans there are a total of 29 blood group systems based on antigens on the surface of the red blood cells, but the ABO and Rhesus factor (positive or negative) are the commonly used groups to determine blood type. PowerPoint Presentation: Human ABO Blood Types Image courtesy of Wikipedia. PowerPoint Presentation: Many blood types and groups have been identified in domestic animals. Cattle have 9 recognized blood groups; Horses have 8 recognized blood groups; and Canine have 13 described groups, but only 8 recognized groups.