Circulatory-System-STEM.ppt
- 2. What is the cardiovascular system? The cardiovascular system consists of a network of vessels that circulates blood throughout the body, motored by the action of the heart. We’ll be talking about specifics of the heart in a separate lesson, so will concentrate here on the circulatory system.
- 3. Tracing the flow of blood…pulmonary circulation The inferior vena cava is the largest vein of the body. It carries de-oxygenated blood back from the lower part of the body to the right atrium of the heart. This blood is carrying carbon dioxide. The superior vena cava is above the heart and carries de-oxygenated blood from the head and arms to the right atrium of the heart.
- 4. Tracing the flow of blood…pulmonary circulation From the right atrium, the blood flows through the tricuspid valve to the right ventricle and then onto the lungs through the pulmonary valve and pulmonary artery.
- 5. In the lungs, the blood exchanges the carbon dioxide it is carrying for oxygen. Tracing the flow of blood…pulmonary circulation
- 6. Tracing the flow of blood…pulmonary circulation The fully oxygenated blood now flows BACK to the left atrium of the heart through the pulmonary veins.
- 7. Tracing the flow of blood…systemic circulation The oxygenated blood leaves the left atrium through the mitral (bicuspid) valve into the left ventricle, gets pumped from the left ventricle through the aortic valve to the aorta.
- 8. Tracing the flow of blood…systemic circulation The aorta is the largest artery of the body. The ascending aorta leaves the heart, curves in an inverted ‘U’ shape making an arch, and then descends downward.
- 9. Tracing the flow of blood…systemic circulation At the arch of the aorta, 3 branches extend upward… 1. The brachiocephalic artery (or innominate artery) quickly divides into the right subclavian artery that supplies blood to the right arm and upper torso AND the right common carotid artery that supplies the head and neck.
- 10. Tracing the flow of blood…systemic circulation At the arch of the aorta, 3 branches extend upward… 2. The left common carotid artery supplies the head and neck. 3. The left subclavian artery supplies the left arm and upper torso. ‘Subclavian’ means it is located below the clavicle… or collarbone.
- 11. Tracing the flow of blood… the arteries Arteries are elastic tubes that carry blood in pulsating waves. The blood exerts pressure against the walls of the arteries as it passes through. The peak pressure occurs during the heart’s contraction, and is called systolic pressure. The minimum pressure occurs between contractions when the heart expands and refills, and is called diastolic pressure. This pressure variation within the artery produces a pulse. All arteries have a pulse.
- 12. Tracing the flow of blood… the arteries Common pulse sites used to check circulation are: 1. TEMPORAL (TEM por ul) - side of forehead 2 & 3. CAROTID (kuh RAH did) - neck 4. BRACHIAL (BRAY kee ul) - inside the elbow 5. RADIAL - thumb side of wrist 6. FEMORAL (FEM er all) - groin 7. POPLITEAL (pah plah TEE ul) - behind the knee 8 & 9. DORSALIS PEDIS (dor SAL us PED iss) - upper surface of foot
- 13. Arterioles act like adjustable nozzles in the circulatory system, so they have the greatest influence over blood pressure. Tracing the flow of blood… the arterioles The arteries branch off into even smaller vessels called arterioles, and then to smaller vessels yet called capillaries.
- 14. Tracing the flow of blood… the capillaries The capillaries are the smallest of the blood vessels, and the walls are so thin that molecules can pass through them. They branch out from the arterioles, passing next to the organs, intestines, and through all the cellular tissue. In the cellular tissue, the capillaries provide the means of exchange, through the process of absorption.
- 15. Tracing the flow of blood… the capillaries The capillaries branching away from the arteries in the abdomen pass by the liver and intestines, picking up nutrients and water. The capillaries in the cellular tissue exchange their oxygen, nutrients, and water… and pick up carbon dioxide and other wastes. The capillaries branching away from the arteries in the lungs absorb oxygen.
- 16. Tracing the flow of blood… the venules The capillaries, now carrying carbon dioxide and cell wastes, start merging into bigger vessels called venules (VEEN or VEN yoo als) The venules widen even further, emptying into veins.
- 17. The veins have valves that prevent the backflow of blood. Veins lead back to the heart. Tracing the flow of blood… the veins
- 18. Veins are the vessels that are used to remove blood from the body for analysis. Tracing the flow of blood… the veins This procedure is called a venipuncture (VEEN ah punk chur) and the medical personnel that specializes in this procedure is called a phlebotomist (flah BOTT ah mist).