The Cardiovascular System

1. The Cardiovascular System

2. What do you think of when you hear the word, heart? The heart is the main organ that is used in the circulatory system. The circulatory system includes your heart, blood, veins, capillaries, arteries, and your lymphatic system. Your heart creates pressure every time it beats, pumping blood throughout your body. The cardiovascular system consists of the heart an three types of blood vessels that carry blood throughout your body.

3. “Cardio”-means heart • “vascular”-means blood vessel • The capillaries, veins, and arteries carry blood pumped by the heart. Figure 1 p 606.

4. The Heart • Your heart is an organ made mostly of cardiac muscle tissue. Your heart is about the size of your fist and is almost in the center of your chest cavity. • The right side of the heart pumps oxygen-rich blood to the lungs. • The left side pumps oxygen-rich blood to the body. • The upper chamber is called an atrium (artery) and the lower chamber is called a ventricle.

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6. Between each atrium and ventricle are flaplike structures called valves, these prevent blood from being pumped backwards. • Feel your heart, can you hear it beating. The lub-dub, lub-dub sound…That is the noise of the valves closing. • In figure 3 it shows the flow of blood throughout the heart.

7. Three types of blood vessels • Arteries-carry blood away from the heart, have thick walls, each heart beat pumps blood into your arteries at high pressure-this is your blood pressure. • Capillaries-tiny blood vessel that allows gas exchange between the body cells and blood, narrow walls making blood cells to follow in a single file line, no cell in the body is more than 3-4 cells away from a capillary.

8. Three types of blood vessels • Veins-after leaving the capillary, blood enters the veins, these carry blood back to the heart, valves keep blood from flowing backwards in the veins. When skeleton muscles contract they squeeze the veins pushing blood back to the heart

9. Circulation • the continuous movement of blood through the heart and blood vessels, which is maintained chiefly by the action of the heart, and by which nutrients, oxygen, and internal secretions are carried to and wastes are carried from the body tissues. • Your heart pumps blood to the lungs where carbon dioxide is leaves the blood and oxygen is restored in the blood, then flowing back to the heart and then being shipped out to the other parts of the body.

10. cIRCULATION • Pulmonary circulation- moving oxygen rich blood from lungs to the heart. • Systemic circulation- moving oxygen-rich blood from the heart to the rest of the body. • Figure 5 p 609

11. Cardiovascular Problems • More than just your blood vessels and heart may be harmed from cardiovascular problems. Smoking, high cholesterol, physical inactivity, or heredity may cause cardiovascular problems. • In the US the leading cause of death is heart disease. The major cause of heart disease is what we call athersclerosis. This happens when cholesterol builds up in the inside of a blood vessel. A clogged artery can cause a heart attack.

13. Atherosclerosis • Atherosclerosis can also be caused by hypertension, which is abnormal blood pressure. • The higher the blood pressure the greater the risk for a heart attack, heart failure, kidney disease, and stroke. • Stroke-is when a blood vessel in the brain becomes clogged or ruptures, leaving the brain no way to get oxygen. This results in the death of brain cells.

14. Heart Attack vs. Heart Failure • A heart attack happens when muscle cells die and part of the heart muscle is damaged. Figure 7 p611 • Heart failure happens when the heart cannot pump enough blood to meet the body’s needs. Resulting in the damage of other vital organs.

15. Chapter 23 • Section 2: BLOOD

16. Blood • Gas is to a car, as blood is to the body. • The human body has about 5 l of blood circulating through it. Blood is a connective tissue made up of plasma, red blood cells, platelets, and white blood cells. Blood cells carry oxygen and nutrients to different parts of your body.

17. Plasma-fluid part of blood; mixture of water minerals, nutrients, sugars, proteins, and other substances; RBC, WBC, and platelets are found in plasma. • RBCs-RBCs have hemoglobin (an oxygen carrying protein); gives RBCs their color.

18. Platelets-pieces of large cells found in bones marrow; last for about 5-10 days; form a clump when you cut yourself (figure 2 p 613); release chemicals that react with proteins in plasma causing fibers to form causing a clot. • WBCs-help to keep you healthy by destroying pathogens( bacteria or virus); some look for pathogens while others release antibodies (chemicals that identify or destroy pathogens); most are made in bone marrow.

19. Blood Jobs • Your blood does not only deliver oxygen to parts of your body, it also regulates your body temperature. • When your body temperature is rising it signals blood vessels in your skin to enlarge, allowing heat from your blood to heat up your skin. When your body temperature is normal-your blood vessels go back to their original size.

20. Every time your heart beats, it pushes blood out of the heart and into your arteries. The force exerted by blood on the inside walls of the arteries is called blood pressure. • Read the second paragraph under blood pressure p 614.

21. There are 4 blood types (A, B, AB, O) the letter refers to the type of chemicals on the surface of the RBC’s. (A has “A” antigens, B has “B” antigens, AB has both “A” and “B” and O has neither).

22. Lymphatic System • The group of organs andL tissues that collect the excess fluid and return it to your blood. • Lymph- the fluid that is collected by the lymphatic vessels and nodes. • Lymph nodes-small bean shaped groups of tissues that remove pathogens and dead cells from the lymph. Found in the armpit, necj and groin.

23. Lymphocytes-made in bone marrow and fight off pathogens. • T cells: destroy pathogens • B cells: produce antibodies • Thymus-gland that produces T cells • Spleen-largest, stores and produces lymphocytes. • Tonsils-defend against infection, trap pathogens that enter the throat.

24. Respiratory System • Respiration-the process by which a body gets and uses oxygen and releases carbon dioxide and water. • Inhale and exhale • Cellular respiration • The respiratory system takes in oxygen and releases carbon dioxide.