Chapter 37

1. Chapter 37 The Circulatory and the Respiratory Systems

2. 37-1 The Circulatory System • Vocabulary: • Artery Erythrocyte • Arteriole Anemia • Capillary Leukocyte • Venule Leukemia • Vein platelet • Lymphatic system fibrin • Lymph A-B-O system • Plasma Rh factor

3. objectives • Describe 4 functions of the circulatory system • Compare and contrast the structure and function of arteries, capillaries, and veins • State the function of the lymphatic system • Describe the components of the blood • Explain how blood type is determined

4. Opening questions • Why do our cells need oxygen? • What are advantages of a closed circulatory system? • Groups of 4 Brainstorm ideas to the above questions.

5. Chapter 37-1 • Introduction: • The human body has a closed circulatory system made of a network of vessels that extend to all tissues of the body in order to provide them with food and oxygen. It also serves to take away the wastes that are produced in these tissues such as the muscles, bones, and nervous tissues

6. I. Transport of Materials and Distribution of Heat • A. The Human circulatory system connects the various muscles and organs of the body with one another. Four types of materials are transported through this system • 1. Nutrients and wastes • 2. Oxygen and carbon dioxide (gases) • 3. Hormones • 4. Heat

7. 1. Nutrients and Wastes • a. Food molecules fuel muscle contractions and other cell activities • b. cells receive nutrients from the small intestines • c. wastes are taken from cells to the kidneys where they are filtered out of the blood

8. 2. Gases – Oxygen and CO2 • a. Cells need oxygen for cellular respiration • b. carbon dioxide needs to be taken away from the cells. Too much CO2 can be poisonous to the body.

9. 3. Heat • a. The body maintains a constant temperature by using metabolic energy to make heat. • b. The environment also contributes to the temperature of our body • 1. In the cold blood vessels constrict to try to conserve body heat • 2. In the heat blood vessels dilate and let heat escape the body

10. 4. Hormones • a. The body coordinates the activities of many organs with hormones (chemical messengers of the endocrine system) • b. The circulatory system carries the hormones to the target cells in the body.

11. B. Components of the Circulatory System • A. There are four major components of the human circulatory system • 1. Blood vessels – network of tubes that move the blood throughout the body • 2. Lymphatic vessels – recover fluid that leaks out of the blood vessels • 3. Blood – mixture of specialized cells and fluid • 4. Heart – Muscular pump that moves the blood through the vessels

13. B. Pathway of circulation : Arteries -> Arterioles-> Capillaries-> venules -> veins->Heart

14. 1. Arteries – tubes that carry blood away from the heart. Arterial walls are tough, thick and expandable to accommodate for pressure of the blood forced out of the heart. It has 3 layers of tissue: • a. endothelium – inner thin layer made of epithelial cells • b. smooth muscle layer – middle stretchy layer • c. Connective tissue – protective outer layer • The biggest and thickest of the arteries is the Aorta

16. 2. Capillaries • a. thin walls – simple tubes one cell thick for the exchange of gases • b. Narrow in diameter – only slightly wider than one red blood cell so oxygen can diffuse out of the red blood cell into the body cell • 5 % of our blood is in our capillaries. Capillaries put end to end would be several thousand miles in length – able to stretch across the U.S.

17. 3. Veins • a. Return blood to the heart. • c. Contain valves to keep blood flowing in the same direction – working against gravity and not having the same pressure to move the blood as the arteries have. • d. Have the same layers as arteries but they are not as thick or tough. • c. The largest vein in the body is the VENA CAVA leading into the heart.

21. 4. Lymphatic Vessels • a. Fluids that do not return to capillaries collect in spaces around the body’s cells – sometimes causing swollen feet or hands. • b. Lymph – fluid of the lymphatic system • c. Lympahtic vessels – collect the fluid surrounding cells and carries it to ducts that drain into veins in the neck. These vessels contain valves similar to the ones in veins. The Lymph is pushed through the vessels by contracting muscles in the arms and legs. • d. Lymph nodes – filter foreign substances from the lymph before it returns to the circulatory system. An infection in the body may cause the nodes to swell. They are concentrated in the armpits, neck, and groin areas • e. Thymus, tonsils, spleen, appendix, and bone marrow all contain lymph tissue for fighting infections

23. C. Blood Components • A. Plasma – liquid portion of the blood • 1. 90% water • 2. Metabolic Wastes – glucose, food molecules, vitamins, hormones, and nitrogen wastes • 3. Salts and Ions – sodium, chloride, bicarbonates, and traces of calcium, magnesium, metallic ions (copper, potassium, and zinc) • 4. Proteins – keep plasma from losing water to the body cells.

24. B. Blood Cells • 1. Red blood cells – erythrocytes • Round flat disks that are collapsed in the center • Center carries the protein hemoglobin – binds to oxygen. • Does not have a nucleus • Can NOT repair itself or make proteins • Life span of about 120 days • Produced in the bones red bone marrow by stem cells.

25. ANEMIA – a decrease of hemoglobin in the blood. • Anemia reduces the amount of oxygen that RBCs can transport resulting in a lack of energy, shortness of breath on minor exertions, listlessness, pale skin and a general feeling of fatigue. There are a number of types of anemia: • Iron-Deficiency Anemia – Most common – vitamin B12 deficiency, nutritional deficiencies, excessive iron loss

26. 2. White Blood Cells – Leukocytes • a. Larger in size then RBCs • b. smaller amount - 1/1000 RBCs • c. primary cells of the immune system i. Lymphocytes – produce antibodies ii. Macrophages – Wonder out of cells to fight infections. d. Cancer of the White Blood Cells is called leukemia

27. 3. Platelets – Thrombocytes • a. cell fragments that lack a nucleus • b. play a role in blood clotting (coagulation) • c. Lack of the clotting protein results in a genetic disorder called hemophilia

28. d. Hemostasis is the stoppage of blood flow leading to coagulation. Hemostasis has 3 stages. • 1. Platelet plug forms – platelets become sticky and stick to the damaged site. As the platelets pile up the small mass is called a platelet plug. • 2. Vascular spasms and vessel dialation - serotonin • 3. Coagulation – Prothrombin is converted to thrombin which joins fibrinogen to make fibrin which acts as a net to capture RBCs and form the clot. • Normally, blood clots within 3 to 6 minutes.

29. Undesirable clotting • Thrombus – a clot in an unbroken blood vessel. Usually occurs in the legs. If large enough, it may prevent blood flow to cells beyond the blockage. If a thrombus forms in the vessels of the heart it is called a coronary thrombosis which may cause a fatal heart attack. • Embolus – a moving thrombus. Usually not a problem unless it lodges in a narrow blood vessel. This could lead to a stroke.

30. D. Blood Type • A. We use what is called the A-B-O system for typing blood. • B. We determine blood types by the type of antigen found on the surface of the RBCs. • A Antigen = A blood • B antigen = B blood • Both A, B antigens = AB blood • No Antigens = O blood

31. C. Antibodies in our blood plasma act against foreign antigens and may cause clumping (agglutinate) of the blood which could be fatal. • A type have B antibodies • B type have A antibodies • AB blood has no antibodies • O blood has both A & B antibodies • Before a blood transfusion can be performed it is important to know the blood type of the donor and the recipient. Many other makers are considered before blood is given to another person.

33. Rh factor • D. Rh factor - named for the Rhesus monkey where it was first discovered. • Another type of antigen found on the surface of the blood. • Those that have the antigen are Rh+ • Those that do not have the antigen are Rh- • Most Americans are Rh+ • This plays a role in pregnancy. If an Rh- mother carries an Rh + baby the first pregnancy will be normal, but the mother will produce antibodies to the Rh- blood, so the second pregnancy the antibodies from the mother’s blood will attack the child’s RBCs. This is called erythroblastosis fetalis. Today this is rare because the mother can be given a drug called RhoGAM immediately after her first birth.

34. 37-2 The Heart • I. The human heart is a double pump made of 4 chambers. One side powers an oxygen acquiring phase, while the other side powers an oxygen delivery phase. • A. The Heart pumps blood in two separate loops. • 1. Pulmonary circulation – Heart to lungs and back. • a. right side of the heart • b. Deoxygenated blood receives oxygen in the lungs and releases it’s carbon dioxide in the lungs.

35. 2. Systemic Circulation – delivers blood to the body tissues and returns it to the heart. • a. Left side of the heart • b. Oxygenated blood is pushed out to the bodies tissues to deliver oxygen and pick up wastes including carbon dioxide to deliver back to the heart.

37. B. Path of blood through the heart • 1. Blood enters the heart from the body through the vena cava. The upper half through the superior vena cava and the lower half through the inferior vena cava. • 2. The right atrium receives the blood from the vena cava. • 3. It then flows through the tricuspid valve to the right ventricle. • 4. The right ventricle then pushes the blood through the pulmonary valve into the pulmonary artery.

38. 5. The pulmonary artery takes the blood to the right and left lungs. • 6. It then returns to the heart through the pulmonary veins which empty it into the left atrium. • 7. It then flows through the bicuspid (mitral) valve to the left ventricle. • 8. The left ventricle then pumps the blood through the aortic valve to the aorta where it is delivered out to the body.

40. C. The chambers • 1. Atria are the upper receiving chambers. • 2. Ventricles are the more muscular lower pumping chambers. • 3. The atria contract simultaneously to pump blood to the ventricles. Both ventricles then contract together to push blood out of the heart.

42. D. The valves • 1. The atrioventricular valves are found between the atria and the ventricles. • a. Tricuspid – between the rt. Atrium and rt. Ventricle. 3 flaps. • b. Bicuspid (mitral) valve – between the left atrium and left ventricle. 2 flaps.

43. 2. Semilunar valves – valves between the ventricles and the vessels • a. Pulmonary valve – valve between the right ventricle and the pulmonary artery. • b. Aortic valve – valve between the left ventricle and the aorta. • Cords called chordae tendineae connect the flaps of the valves to muscle projections called papillary muscles.

44. E. The layers of the heart • 1. The heart is enclosed in a loose fitting serous membrane known as the pericardial sac. The sac is made of two layers. • a. Fibrous pericardium – outer layer, protects and anchors the heart • b. Serous pericardium – thin inner layer next to the heart – also called the epicardium.

45. 2. Heart wall layers • a. Epicardium (serous pericardium) – thin outer transparent layer. Inflammation of this tissue due to friction is called pericarditis. • b. Myocardium – thick muscular layer of the heart that makes up the bulk of the heart • c. Endocardium – thin inner layer lines the myocardium and covers the valves of the heart and the chordae tendineae of the valves.

46. F. Contractions of the Heart • Contractions of the heart are controlled by the autonomic nervous system. The heart also has its own regulating system called the conduction system that generates and distributes electrical impulses over the heart to stimulate cardiac muscle fibers to contract.

47. Sinoatrial node • 1. The system begins at the sinoatrial node known as the SA node or pacemaker. The SA node initiates each cardiac cycle and sets the pace for the heart rate. • a. The SA node is located in the upper right atrium • b. It stimulates both atria to contract at the same time.

48. Contraction of the Ventricles • 2. The contraction of the atria then stimulates the atrioventricular node (AV node) which is located in the lower portion of the right atrium. • 3. From the AV node a tract of conducting fibers called the bundle of His runs between both ventricles separating into left and right branches. The bundle of His stimulates the medial portion of the ventricles.

49. 4. The actual contraction of the ventricles is stimulated by the Purkinje’s fibers that emerge from the bundle branches and pass into the myocardium of the ventricles.

50. On the average heart contractions are initiated at a rate of about 72 beats per minute. During sleep this rate decreases. During exercise this rate increases.