Monday March 23 rd 2015

1. MondayMarch 23rd 2015 • Bell Ringer (index card) • About how much blood (in liters) does your body hold? About 5 Liters! That’s 2 ½ soda bottles

2. The Circulatory System

3. The Circulatory System • Also called the cardiovascular system • Is made of 3 parts: • Heart • Blood • And blood vessels • Allows blood to flow to all parts of your body • Has 3 main jobs: • Carries needed substances to cells • Oxygen and glucose • Carries waste products away from cells • Carbon dioxide • Contains cells that fight disease - White blood cells

4. The Heart

5. The Heart • A hollow muscular organ that pumps blood throughout the body • About the size of your fist • Located in the center of the chest, beneath the sternum and inside the ribcage • Made of cardiac muscle • Contracts over and over without tiring out

6. The Heart • Acts as two pumps • Right side: pumps blood into the lungs where it picks up oxygen • Left side: pumps blood into the arteries where it is sent throughout the body • The two sides are separated by a wall of tissue called the septum.

7. The Heart • Each side has two chambers • The upper chambers are called atria. • The lower chambers are called ventricles.

8. The Atria (Atrium) • The upper chambers of the heart • Job is to receive blood that comes into the heart • The right atrium has a group of cells called the pacemaker (sinoatrial node) that sends signals to make the heart muscle contract

9. Pacemaker • Whenever someone has problems with an irregular heartbeat, doctors may give them an artificial pacemaker. • This helps their heart maintain a normal rhythm.

10. Ventricles • The lower chambers • Job is to pump blood out of the heart • Right ventriclepumps blood to the lungs • Left ventriclepumps blood into the body

11. Valves • The ventricles are separated from the atria by valves • Flaps of tissue that prevents blood from flowing backward • Also located between the ventricles and the large blood vessels that carry blood out of the heart

12. How the Heart Works • Two phases • Heart muscle relaxes and atria fill with blood • Heart muscle contracts and blood pumps forward • This closes the valves between the atria and the ventricles • Creates the lub sound • The valves between the ventricles and the blood vessels snap shut • Creates the dup sound

13. Two Loops • Overall pattern of blood flow in the body is like the figure eight. • In the first loop, blood travels from the heart to the lungs and then back to the heart. • In the second loop, blood is pumped from the heart throughout the body and then returns to the heart. • Blood travels in only one direction. • One drop of blood could make the journey through both loops in less than a minute.

14. Video http://www.youtube.com/watch?v=18--LFIs-FM

15. Blood Vessels • There are three kinds of blood vessels • Arteries • Carry blood away from the heart • Veins • Carry blood to the heart • Capillaries • Exchange substances (gases) between the blood and body cells

16. To be continued…

17. Blood

18. Blood • Blood is made of four components, or parts: • Plasma, red blood cells (RBCs), white blood cells (WBCs), and platelets • About 45% of the volume of blood is cells; the rest is plasma

19. Plasma • Most of the materials transported in the blood travel in the plasma. • Plasma is the liquid part of blood. • 90% of plasma is water • 10% is dissolved materials, such as glucose, fats, vitamins, and minerals • Many waste products are carried away by the plasma

20. Plasma • Proteins give plasma its yellow color • Three groups of plasma proteins • Helps regulate amount of water in blood • Helps fight disease • Interacts with platelets to form blood clots.

21. Red Blood Cells(RBCs) • RBCs take up oxygen in the lungs and deliver it to cells throughout your body • Produced in the bone marrow (like other blood cells) • Look like doughnuts that someone forgot to cut out the hole • Because they are thin in the middle, they are able to bend and twist easily • Allows them to squeeze into tiny capillaries

22. RBCs • Made mostly of hemoglobin, an iron-containing protein that chemically binds to oxygen. • Hemoglobin is also able to pick up some carbon dioxide, but most is carried by the plasma • When hemoglobin and oxygen join together, the cell becomes bright red; without oxygen, the cell is dark red • Arteries have blood that is bright red • Veins have blood that is dark red

23. RBCs • Mature RBCs have no nuclei • Without a nucleus, it cannot reproduce or repair itself • Only are able to live 120 days • Every second, about 2 million RBCs die • Bone marrow makes new cells at the same rate

24. White Blood Cells(WBCs) • Produced in the bone marrow • WBCs are the body’s disease fighters. • Some recognize disease causing organisms and alert the body that it has been invaded • Others produce chemicals to fight the invaders • Others surround and kill the invaders

25. WBCs • There are fewer WBCs than RBCs. • Larger than RBCs • Several different types of WBCs • WBCs have nuclei • Can live for months or even years

26. Platelets • Platelets are cell fragments that play an important role in forming blood clots

27. Forming Clots • When a vessel is cut, platelets collect and stick around the cut. • Platelets release a chemical that leads to the production of a protein called fibrin. • Fibrin makes a net of fibers across the wound. • This net traps blood cells. • As more and more of the platelets and cells get caught in the fibrin net, a clot forms. • A scab is a dried blood clot on the skin’s surface

28. Blood Types • Four major blood types: A, B, AB, O • Types are determined by the proteins known as marker molecules that are on RBCs • A has the A marker, B has the B marker, AB has both A and B, O has no markers on it

29. Blood Types • Plasma has proteins that recognize cells with foreign markers and they make those cells clump together • A has anti-B proteins • B has anti-A proteins • AB has no anti-proteins • O has both anti-A and anti-B proteins

30. Why is Blood Type Important? • Your blood type determines what type of blood you can safely receive in a blood transfusion. • If you are A, you can receive A and O blood • If you are B, you can receive B and O blood • If you are AB, you can receive, A, B, AB, and O • “Universal recipients” • If you are O, you can only receive O blood • “Universal donors”

31. Cardiovascular Diseases • Cardiovascular disease is the leading cause of death in the U.S. today.

32. Atherosclerosis • Atherosclerosis is a condition in which an artery wall thickens as a result of the buildup of fatty materials such as cholesterol. • This reduces the flow of blood in the affected artery.

33. Atherosclerosis • When atherosclerosis develops in the coronary arteries, the heart muscle receives less blood (less oxygen), which can lead to a heart attack. • Heart attacks occur when the blood flow to part of the heart muscle is blocked. • Cells die in the part of the heart that does not receive blood and oxygen. This permanently damages the heart

34. Treating Atherosclerosis • Low-fat diet and exercise for mild cases. • Some medications can be prescribed. • Severe cases may lead to angioplasty, where a small balloon is inserted into the blocked artery to help open it up. • When arteries are completely blocked, a bypass operation may be performed. • In a bypass, a vein from the leg is used to create an alternate path for blood to flow into the heart muscle.

35. Hypertension • Hypertension is high blood pressure. • A person will have hypertension if their blood pressure is consistently greater than 140/90. • High blood pressure makes the heart work harder to pump blood through the body, possibly damaging the walls of the blood vessel. • Because most people have no obvious signs of the disease it is called the “silent killer”.

36. Treating High Blood Pressure • Closely related to atherosclerosis. • As arteries narrow, the blood pressure increases. • Diet and exercise help • Limit intake of salt • Sometimes given medications that lower blood pressure

37. Measuring Blood Pressure • Blood pressure is measured by a device called a sphygmomanometer • The first number in a blood pressure reading is the measurement of the blood pressure when the ventricles contract. • The second number, which is lower, is the blood pressure when the ventricles relax. • The blood pressure is given as a fraction with the contraction pressure, or systolic, over the relaxation pressure, or diastolic. • A healthy blood pressure is 120/80 or lower.