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Cardiovascular System

Cardiovascular System. Blood.

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Cardiovascular System

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  1. Cardiovascular System

  2. Blood • Blood is a viscous fluid. It is thicker and more adhesive than water. It has an average temperature of 100.4 degrees. It constitutes 8% of the total body weight. The average man has 5-6 quarts, and the average woman has 4-5 quarts. The blood is made up of formed elements and plasma

  3. The Formed Elements Are: • 1. Erythrocytes (Red Blood Cells) • 2. Leucocytes (White Blood Cells) • 3. Thrombocytes (Platelets)

  4. … • Hematopoieses or red blood cell production takes place in the bone marrow. Most white blood cells are produced in the spleen, tonsils, and lymph nodes.

  5. Blood Functions: • 1. Transport Oxygen from the lungs to all cells. • 2. Transport Carbon Dioxide from the cells to the lungs. • 3. Transports nutrients from the digestive organs to the cells. • 4. Transports waste products from the cells to the kidneys, lungs, and sweat glands. • 5. Transports hormones form the endocrine glands to cells.

  6. Blood Functions Continued: • 6. Transports enzymes to cells. • 7. Regulates body pH through buffers and amino acids. • 8. Regulates normal body temperature because it contains a large volume of water. • 9. Regulates water content of cells. • 10. Prevents body fluids loss through clotting mechanisms. • 11. Protects against toxins and microbes through special combat-unit cells.

  7. Plasma • When the formed elements are removed from blood, a straw colored liquid is left. This is plasma. Plasma contains the following components… • 1. WATER – makes up 92% of plasma. Most comes from the absorption process from digestion. It acts as a solvent and absorbs heat. Also acts as a suspending agent for solids.

  8. Plasma • 2. SOLUTES: • A. Proteins- Make up 7-9% of plasma • a. Albumins – produced by liver. Provides blood with viscosity and regulates blood volume. b. Globulins – important for anti-body protection. c. Fibrogen – produced by the liver and plays an essential role in clotting

  9. Plasma • B. Nonprotein Nitrogen – Includes urea, uric acid, creatine, ammonium, and salts. These are the products of metabolism and are being carried to the organs of exretion. • C. Food Substances – include amino acids, glucose, and fats. • D. Regulatory Substances – Include enzymes that produce chemical reactions and hormones that regulate growth and development. • E. Respiratory gases – oxygen and carbon dioxide. • F. Electrolytes – maintain osmotic pressure, normal pH and physiology balance between tissues and blood.

  10. The formed elements • See hand out

  11. Blood Vessels • Blood vessels are the network of tubes that carry the blood. • Blood vessels are divided into 5 types : • 1. Arteries • 2. Arterioles • 3. Capillaries • 4. Venules • 5. Veins

  12. Arteries • Vessels that carry blood away from the heart. Arteries are thicker and stronger than veins. The pressure is always greater in arteries than in veins. An artery has 3 layers that make up their walls. The middle layer is made up of smooth muscle which gives the vessel its elasticity. The hollow core is called the lumen

  13. Arteries… continued.. The two major properties of arteries are elasticity and contractibility. The smooth muscle is rounded like doughnuts around the vessel. When the ventricles contract, the arteries expand with the entry of blood. When ventricles relax the arteries recoil, pushing the blood. Vasoconstriction, a decrease in the size of lumen, and vasodilatation and increase, can be caused by temperature, chemical and injury.

  14. Larger arteries divide into arterioles. As they enter tissue they branch into microscopic capillaries.

  15. Capillaries • Walls are constructed of single cells. They permit exchange of nutrient and gases between the blood and interstitial fluid. They are only large enough for one blood cells to pass through one at a time.

  16. Veins • Veins return the blood to the heart. Generally composed the same as arteries with less elasticity and smooth muscle. Vein walls are not as strong as arteries and this leads to problems such as varicose veins and hemorrhoids. These occur when the walls of the vein become weak and blood pools the vein.

  17. Blood Pressure • Blood pressure is the measure of pressure exerted against the artery walls. • Blood pressure is measured with two numbers ex. 120/80. • The top number is the systolic number. It’s the force with which the blood pushes against the artery walls when the ventricles are contracting. • The lower number is the diastolic pressure. It is the pressure against the artery walls when the ventricles are relaxed. Hypertension is high blood pressure.

  18. Causes of High Blood Pressure • 1. Genetic (family history) • 2. Obesity • 3. Stress • 4. Smoking • 5. Lack of exercise • 6. Age

  19. Circulatory Routes • 1. Systemic Route – the largest route. Include all the oxygenated blood that leaves the left ventricle and return to the right atrium. Has many subdivisions..

  20. Subdivisions of Systemic Routes • A. Coronary Circulation – supplies the myocardium of the heart.

  21. Subdivisions of Systemic Routes • B. Hepatic Portal System – runs from the digestive tract to the liver. Contains venous blood flowing from the digestive organs to the liver. Very rich with nutrients and the liver monitors these substances before they pass into the general circulation. The liver also detoxifies substances that have been absorbed by the digestive organs. Includes veins that drain the pancreas, spleen, stomach, intestines, and gallbladder and transport it to the liver.

  22. 2. Pulmonary Circulation – The route of blood through the heart and lungs.

  23. The Heart • The heart is the workhouse of the cardiovascular system. It is a hollow, muscular organ that pumps blood continually your entire lifetime. • Each day the average heart beats over 100,000 times and moves about 2000 gallons of blood. In a 70 year life time, the heart will beat over 2.5 billion times.

  24. Parts of the Heart • 1. Pericardium – tough, loose fitting membrane which encloses the heart. It provides a tough protective covering and anchors the heart inside the internal cavity. It is actually two membranes with a small cavity between them. This cavity contains a watery fluid, pericardial fluid, which prevents friction between the membranes as the heart moves.

  25. Parts of the Heart • 2. Walls – the bulk of the heart is known as the myocardium which is cardiac muscle tissue. The myocardium is responsible for the contractions of the heart. • Chambers-The heart can be divided into 4 chambers. The 2 upper chambers are called atriums and the bottom 2 ones are called ventricles. The septum is the thick wall that roughly divides the two sides of the heart. The walls of the left ventricle are the thickest because it must work the hardest.

  26. Parts of the Heart • 3. Valves – blood is prevented from flowing backwards by valves. A. Tricuspid valve – between the right atrium and the right ventricle. Made up of 3 flaps. Cords called the chordae tendinae connect the ends of the flap to small muscles called papillary muscles. B. Pulmonary valve – between right ventricle and pulmonary artery. C. Bicuspid valve (Mitral) – between the left atrium and the left ventricle. These also contain the chordae tendinae and papillary muscles. D. Aortic valve – between the left ventricle and the aorta.

  27. The Path of Blood • The right atrium receives the blood from all parts of the body through the vena cavas. The right atrium then squeezes the blood into the right ventricle though the tricuspid valve. The blood then passes through the pulmonary valve into the pulmonary artery. This artery carries the blood to the lungs. The pulmonary artery is the only artery to carry deoxygenated blood. In the lungs the blood releases its CO2 and takes on oxygen. It returns to the heart via 4 pulmonary veins that empty into the left atrium. The blood is then squeezed into the left ventricle through the bicuspid valve. From here the blood is passed into the aorta and into the rest of the body.

  28. Heart Sounds • The sounds the heart makes are not the sounds of the heart muscle, but the blood flowing through the valves. • The first sound usually sounds like a “lubb”. It is created by the closure of the atrioventricular valves. • The second sound is a “dubb”. It is created by the closing of the semilunar valves.

  29. Health Applications • 1. Anemia – caused by insufficient erythrocytes or hemoglobin. Generally causes fatigue and intolerance to cold. • 2. Polycythemia – abnormal increase of red blood cells. Increases blood viscosity which leads to high blood pressure and thrombosis. • 3. Infectious mononucleosis – viral disease that elevates the white blood cells. Symptoms include slight fever, sore throat, stiff neck, and general malaise.

  30. 4. Leukemia – “cancer of the blood”. It is an uncontrolled greatly accelerated production of W.B.C. death occurs from hemorrhaging in the brain and infection since W.B.C. do not mature. • 5. Atherosclerosis – occurs when fatty deposits collect along the walls of vessels. Diets high in fat and cholesterol lead to disease. Actually starts in childhood. • 6. Hypertension – high blood pressure.

  31. Heart Disease • Heart diseases account for about 53% of all deaths. Kills more than cancer, accidents, pneumonia, influenza, diabetes combined. • Factors – • 1. high blood cholesterol • 2. high blood pressure • 3. cigarette smoking • 4. obesity • 5. lack of exercise • 6. diabetes mellitus

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