The Circulatory System

1. The Circulatory System Round and round we go!

2. What is its purpose? Moves oxygen, nutrients, and wastes in, out, and around the body. It is the transportation system of the human body!

3. What are the structures of the circulatory system? • the heart • blood vessels • blood

4. The Heart – The Vital Pump! • The main function of the heart is to keep blood moving constantly throughout the body. • Large organ made of cardiac muscle cells • All mammals have a 4-chambered heart

5. The Heart – The Vital Pump! • The heart is enclosed in a protective sac of tissue called the pericardium. • In the walls of the heart, two layers of epithelial and connective tissue form around a thick layer of muscle called the myocardium. • Contractions of the myocardium pump blood.

6. The Heart – A Vital Pump! • Atria • two upper chambers of heart • Walls are thinner and less muscular

7. The Heart – A Vital Pump! • Ventricles • two lower chambers of heart • thicker muscular walls • performs more work than atria

8. The Heart – A Vital Pump! • Blood enters the heart through the atria and leaves through the ventricles.

10. Path of blood through the heart • Both atria fill with blood at the same time • Right atrium receives oxygen-poor blood from head and body through 2 large veins (vena cava) • Left atrium receives oxygen-rich blood from lungs through 4 pulmonary veins. • Both atria contract pushing blood into the two ventricles

11. Path of blood through the heart 3. Both ventricles contract • When the right ventricle contracts, it pushes oxygen-poor blood out of the heart and toward the lungs through the pulmonary arteries. • When the left ventricle contracts, it pushes oxygen-rich blood out of the heart through the aorta (largest blood vessel in body) to arteries.

12. Circulation Through the Body • The heart functions as two separate pumps. • Pulmonary Circulation - circulates blood between the heart and the lungs • Systemic Circulation - circulates blood between the heart and the rest of the body

13. Circulation of Blood through the Body

14. Heart Animations Flow of Blood Operation: Heart Transplant High Blood Pressure – Hypertension

15. Heartbeat – Lub, dub..lub, dub… • Each time the heart beats, a surge of blood flows from the left ventricle into the aorta and into the arteries. This surge is called a pulse! • Heart rate is set by the pacemaker, a bundle of nerves located at the top of the right atrium. The pacemaker sends an electrical impulse that tells the atria to contract.

16. Heartbeat – Lub, dub…lub, dub... • The heart is controlled by the medulla oblongata and the nervous system. • Blood pressure is the force that blood exerts on the blood vessels. • Systolic pressure is when the ventricles contract • Diastolic pressure is when the ventricles relax

17. Blood and Blood Vessels • The functions of blood include: • collecting oxygen from lungs, nutrients from the digestive tract, and waste products from tissues. • regulating the body’s internal environment. • helping to fight infections. • forming clots to repair damaged blood vessels.

18. Blood Flow • As blood flows through the circulatory system, it moves through three types of blood vessels: • arteries • capillaries • veins

19. Blood Vessels Pathways of Circulation • Arteries • large, thick-walled, muscular, elastic vessel • carries blood AWAY from heart • blood is under great pressure

20. Blood VesselsPathways of Circulation 2. Arterioles – small branches of arteries

21. Blood VesselsPathways of Circulation • Capillaries • microscopic blood vessels (walls = 1 cell thick) • red blood cells move through single file! • thin capillary walls allow nutrients and gases to diffuse easily between blood cells and surrounding tissues.

22. Blood VesselsPathways of Circulation • Veins • large blood vessels • carries blood from tissues TO the heart • blood is not under great pressure • blood travels uphill! (legs and arms)

23. Your Blood – Fluid Transport

25. PLASMA! • Plasma is the fluid portion of the blood. • Straw-colored and makes up 55% of the total volume of blood!

26. Red Blood Cells: Oxygen Carriers • Round, disk-shaped cells • Carry oxygen to body cells • Make up 44% of blood • Produced in red bone marrow • Spleen and liver dispose of old red blood cells

27. How do they carry the oxygen?Hemoglobin to the rescue! • HEMOGLOBIN (iron-containing protein) - O2 binds to hemoglobin on red blood cells. • Blood passes from the lungs to body cells and O2 is released from the hemoglobin where it is needed . • Hemoglobin carries some CO2 as well as O2. 70% of this CO2 is made into other substances in the body. 30% travels back to the lungs.

28. HEMOGLOBIN!!!!

29. Platelets – The Clotters! • Small cell fragments • Produced from bone marrow • Short life span  living only one week • Help link together a sticky network of protein fibers which forms a scab.

30. ABO Blood Types • 4 blood types: A, B, AB, O • Differences in blood types are due to presence or absence of antigens • Ex: If you have type A blood, you have the A antigen and the anti-B antibody. If you had a blood transfusion with B blood, your body would attack the new blood cells with the anti-B antibodies! NOT GOOD!

31. Rh factor in blood • Rhesus factor or Rh factor • Rh is an inherited characteristic • Rh+ if you have Rh antigen; Rh- if not. • Problems occur in pregnant women.

32. Problems with Rh factor • If mother is Rh- and becomes pregnant with Rh+ baby, at birth their blood will mix and the mother will make Rh+ antibodies. • If she gets pregnant again with a Rh+ baby, her Rh+ antibodies will destroy the red blood cells in the fetus. • Treatment is available to remove the Rh antibodies from her blood so the fetus is not in danger.

34. Diseases of the Circulatory System • Cardiovascular diseases are among the leading causes of death and disability in the U.S. • Atherosclerosis is a condition in which fatty deposits called plaque build up on the inner walls of the arteries. • High blood pressure is defined as a sustained elevated blood pressure of 140/90 or higher.

35. Diseases of the Circulatory System • Heart Attack and Stroke  • If one of the coronary arteries becomes blocked, heart muscle may begin to die from a lack of oxygen. • If enough heart muscle is damaged, a heart attack occurs. • If a blood clot gets stuck in a blood vessel leading to the brain, a stroke occurs.

36. Circulatory System Health  • Ways of avoiding cardiovascular disease include: • getting regular exercise. • eating a balanced diet. • avoiding smoking.

37. The layer of muscle in the heart that pumps blood through the circulatory system is called the • myocardium. • atrium. • ventricle. • vena cava.

38. 2. Oxygen-poor blood from the body enters the heart through the • left atrium. • left ventricle. • right atrium. • right ventricle.

39. The vein that brings oxygen-poor blood from the upper part of the body to the right atrium is the • pulmonary vein. • inferior vena cava. • aorta. • superior vena cava.

40. 4. Blood cells that do not have nuclei and are produced by the red bone marrow are • red blood cells. • lymphocytes. • platelets. • phagocytes.

41. The function of platelets is to • assist red blood cells in carrying oxygen. • destroy viruses and bacteria. • initiate the blood clotting process. • keep capillaries open so blood can flow freely through.