The Cardiovascular System

1. The Cardiovascular System Lindsey Bily Anatomy & Physiology Austin High School

2. What is Blood? • It is the delivery service for the body. • Picks up food and oxygen from the respiratory and digestive system and delivers them to the cells. • Picks up wastes from the cells and takes them to the excretory organs. • Transports hormones, enzymes, buffers, and other substances vital to life. • Heat regulating mechanism. It can absorb lots of heat without raising the fluid temperature.

3. What is Blood? • 8% of a person’s body weight is blood • Male- 5-6 L, female- 4-5 L • When you donate blood, they generally take 1 L from you. That is about 10% of your total blood volume.

4. What is Blood? • Composed of… • Red blood cells (RBCs)- erythrocytes • White blood cells (WBCs)- leukocytes • Platelets- thrombocytes • Plasma is the fluid portion and is mostly water

5. A B A: red blood cells B. Blood smear with all components C. Platelets D. White blood cells D C

6. Red Blood Cells • Do not have ribosomes, mitochondria, or many other organelles. • Contain lots of hemoglobin. That’s why they are red. • They can change shape to fit through tiny blood capillaries. • Testosterone may stimulate RBC production-males typically have more RBCs than women. (5,500,000 vs. 4,800,000 per/mm3

7. Red Blood Cells • Transport oxygen and carbon dioxide. • The total surface area of all the RBCs in an adult is equal to an area larger than a football field for exchanging gases! • Each hemoglobin molecule can carry 4 oxygen or carbon dioxide molecules. • Anemia: having a hemoglobin content of less than 10g per 100/mL of blood (normal~ 12-16 g per 100/mL)

8. Red Blood Cells • Erythropoiesis: RBC formation • Occurs in the red bone marrow and the process takes about 4 days. • Each minute of our life, we replace 200 billion RBCs that have been destroyed! • If the blood oxygen level decreases (higher altitudes) we make more RBCs. • The life span is 105-120 days. They usually break apart in the capillaries as they age. • Macrophages lining the blood vessels phagocytose them.

9. Sickle Cell Anemia • Due to an abnormal type of hemoglobin. • Causes the RBC to change shape and get stuck in capillaries. • Inherit the gene from 1 parent and you have a less severe form called “sickle cell trait”. • Inherit from both parents and you have a more severe case. • Causes strokes, swelling, ulcers, etc. due to blockage in the blood vessels.

10. Sickle Cell Anemia Spleen with sickle cell anemia

11. White Blood Cells • There are 5 types of WBCs that each have a different form of protection for the body. Some destroy bacteria, parasitic worms, ingesting inflammatory chemicals, contain histamine, eat viral infected cells and cancer cells. • WBCs are formed in red bone marrow and in lymphatic tissue.

12. White Blood Cells

13. Platelets • They stick together to form plugs or clots to stop blood flow. • Usually form at the site of injury. • We are always having microhemorrhages in our capillaries. Without platelets we could bleed to death. • Formed in the red bone marrow, lungs, and spleen and “live” about 7 days.

14. Platelets

15. Blood Types • Blood type refers to the antigens that are attached to the RBC membrane. (A, B or Rh) • Type A: A antigens on the RBC • Type B: B antigens on the RBC • Type AB: both A & B on the RBC (universal recipient) • Type O: neither antigens (universal donor) • Blood plasma contains antibodies that are different from the antigens on the RBCs so that you don’t attack your own RBCs.

16. Blood Types

17. Blood Types

18. The Rh System • Rh + blood has the Rh antigen on the RBC. Rh- doesn’t. • Plasma does not have antibodies against Rh naturally. Only if a (-) person has been in contact with Rh (+) blood may they make the antibodies. • Sometimes a mother could be Rh- and her baby is Rh+. During delivery, the blood mixes, and the mom develops the antibodies. • The first baby is born fine, but if the mother has another Rh+ baby in the future, the baby is at risk of dying.

19. Plasma • Liquid part of the blood. • contains… • 90 % water • 10% solutes • Proteins that regulate blood clotting and help with immunity • Glucose, amino acids, lipids • Urea, uric acid, creatinine and lactic acid • Oxygen and carbon dioxide • Hormones and enzymes

20. Blood Clotting (Coagulation) • We need our blood to clot to stop bleeding and prevent loss of body fluid. • Clotting is a series of chemical reactions that happen really fast that causes a net of fibers to be built which traps RBCs.

21. Blood Clotting • Proteins involved… • Prothrombin • Thrombin • Fibrinogen • Fibrin

22. Blood Clotting • You need calcium in order for some of the chemical reactions to occur. If you have a low blood calcium level, you may have trouble clotting. • The pale yellowish liquid left over after the clot has formed is blood serum. It is the blood, minus the blood cells and clotting elements. • You need Vitamin K for the liver to make the clotting proteins. You get this from foods (broccoli, cabbage, asparagus, okra, beans, etc..) and also bacteria in your gut make it.

23. Opposing Clotting • We only want our blood to clot under certain conditions. • Normal blood vessels are very smooth, so platelets can’t attach. That makes sure clotting is not activated. • Heparin is an anti-thrombin in blood that keeps it from clotting.

24. Promoting Clotting • A rough spot in the blood vessel lining will cause clotting as will an abnormally slow blood flow. • Atherosclerosis causes rough spots due to the cholesterol-lipid plaques that have built up. • People who are immobile can get clots (thrombosis) since blood flow decreases. • Once started, a clot continues to grow unless medicine is taken to stop it.

25. Blood Disorders • Most blood disorders are due to the tissues not forming blood cells properly. • If a blood disorder is suspected, bone marrow is taken from the pelvis and tested. • A bone marrow transplant may be required.

26. RBC Disorders • Anemia: inability to carry sufficient oxygen to the body’s cells. • Polycythemia: too many RBCs and it becomes too thick to flow properly. • Aplastic anemia: too few RBCs. Causes by destruction of bone marrow by drugs, toxic chemicals, radiation, or cancer. • Pernicious anemia: low # of RBCs. Deficiency of Vitamin B12. Usually due to a problem with the stomach that doesn’t allow you to absorb it. • Folate-deficiency anemia: low # of RBCs due to a deficiency in folic acid (Vitamin B9). Common in alcoholics and other malnourished individuals.

27. Hemoglobin Problems • Iron-deficiency anemia: too little iron means that you can’t make hemoglobin. • Sickle Cell Anemia • Thalassemia: Similar to sickle cell anemia. Abnormal hemoglobin causes changes in RBC shape.

28. WBC Disorders • Leukopenia: too few WBCs (HIV/AIDS). • Leukocytosis: too many WBCs (usually caused by bacterial infection). • Leukemia: a group of malignant disorders where adult stem cells replace normal cells. They can eventually leave the bone marrow and travel to other parts of the body.

29. Clotting Disorders • Thrombus: clot that stays in the place where it was formed. The condition is called thrombosis. • Embolus: When the clot dislodges and circulates through the bloodstream. Called an embolism. • Drugs that can prevent clotting are Heparin (prevents prothrombin from turning into thrombin) and Coumadin (prevents Vitamin K from stimulating the liver to produce clotting proteins).

30. Clotting Disorders • Hemophilia: X-linked disorder and affects 1 in 10,000 males. Failure to produce 1 or more of the clotting proteins. • Thrombocytopenia: low levels of platelets. Caused by destruction of bone marrow due to drugs, immune system diseases, chemicals, radiation or cancer. • Bleeding from many small blood vessels in the body.

31. The Heart • 4 chambered pump the size of a fist. • Weighs 310g (males) and 225g (female) • Heart Coverings • Pericardium-sac that surrounds the heart. Contains pericardial fluid that protects the heart from friction while pumping. • Myocardium- the bulk of the heart wall made up of cardiac muscle . • Endocardium- inner layer of the heart. Very delicate layer.

32. Chambers of the Heart • 4 Chambers • 2 upper: right and left atria • They receive the blood from the body • 2 lower: right and left ventricles • They receive blood from the atria and pump it out to the lungs and the rest of the body

33. Valves of the Heart • The valves permit blood flow in one direction only. • 2 Atrioventricular Valves: Also called “cuspid” valves • Right AV Valve (tricuspid)-right atrium to right ventricle • Left AV Valve (bicuspid)-left atrium to left ventricle • 2 Semilunar Valves • Pulmonary Semilunar valve: right ventricle to pulmonary artery • Aortic Semilunar Valve: left ventricle to aorta

34. Valves of the Heart

35. Blood Flow

36. Blood Supply to Heart Tissue • The heart muscle cells (myocardium) receive blood via the coronary arteries that branch off of the aorta. • The left ventricle cells receive the most blood because it does the most work. • The atria receive blood from a small branch off the coronary arteries. • The right coronary artery is dominant in about 50% of all hearts, left 20% and in 30% neither is dominant.

37. Blood Supply to the Heart • There are few connections between the coronary arteries. • If the main route is blocked, there are few detours. • Myocardial Infarction (MI): Death of oxygen deprived heart muscle cells. This is a heart attack.

38. Blood Supply of the Heart • Cardiac Veins surround the heart and once blood has supplied the cells with oxygen, they enter the vein and go back to the right atrium.

39. Heart Conduction System • Sinoatrial Node (SA node): “pacemaker” of the heart. Sets up the action potential and causes atria to contract. • Atrioventricular Node (AV Node): small mass of special cardiac muscle tissue that lies at the lower part of the right atrium. • Atrioventricular Bundle (AV Bundle): Action potential passes to the ventricles and then down the Purkinje Fibers to cause the ventricles to contract.

40. Heart Conduction

41. Blood Vessels • Carry blood to and from the heart. • Arteries-carry blood away from the heart. All arteries EXCEPT the pulmonary artery carry oxygenated blood. • Veins-carry blood to the heart. All veins EXCEPT the pulmonary vein carry deoxygenated blood.

42. Blood Circulation • Blood leaves the heart Arteriesarteriolescapillariesvenulesveinsback to the heart

43. Functions of the Blood Vessels • Capillaries: microcirculation to every cell • Arteries: “distributors”. Arterioles regulate blood pressure by acting as resistance vessels for the capillaries. • Veins: “collectors and reservoir vessels”. They can stretch called capacitance.

44. Major Blood Vessels • Aorta: serves as the main trunk of the entire systemic arterial system.

46. Blood Vessels • The main arteries and veins lie deep in the body alongside bone- deep veins and arteries • Superficial veins and arteries are the ones that are closer to the skin and you can see.

48. Hepatic Portal System • Veins from the spleen, stomach, pancreas, gallbladder and intestines send their blood to the liver for filtering via the Hepatic Portal Vein. • Purpose: • Liver removes excess glucose from the digestive system blood after a meal. • Liver puts glucose back into the blood when levels are low. • Toxic molecules such as alcohol are partially removed or detoxified before blood goes to the rest of the body.

49. Hepatic portal circulation. In this unusual circulatory route, a vein is located between two capillary beds. The hepatic portal vein collects blood from capillaries in visceral structures located in the abdomen and empties it into the liver. Hepatic veins return blood to the inferior vena cava. (Organs are not drawn to scale.)

50. Fetal Circulation • Fetal blood gets oxygen and food from the mom’s blood as opposed to its own lungs and digestive organs. • Fetuses have additional blood vessels to do this. • Umbilical arteries (2) • Umbilical vein • DuctusVenosus