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Circulatory System

Circulatory System. What is the Circulatory System?. An efficient distribution system for your body that: 1) Distributes nutrients and oxygen to cells 2) Transports hormones throughout your body 3) Carries waste away from cells

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Circulatory System

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  1. Circulatory System

  2. What is the Circulatory System? • An efficient distribution system for your body that: • 1) Distributes nutrients and oxygen to cells • 2) Transports hormones throughout your body • 3) Carries waste away from cells • A system that plays an important role in repairing tissue and protecting the body from infection

  3. Three Primary Components of the Circulatory System • Blood: type of connective tissue made up of cells and liquid • Heart: a multi-chambered, muscular organ that pumps blood through the body • Blood vessels: tubes that form a closed pipeline within the body allowing blood to flow throughout the entire body • Capillaries • Arteries • Veins

  4. Capillaries • The blood vessels that allow close contact with all of the body’s cells. • Microscopic • So narrow that only one blood cell at a time can fit through • Walls are made of a very thin layer of epithelial tissue • This allows diffusion of nutrients and oxygen out of the blood and the diffusion of waste products into the blood

  5. The CAPILLARY Capillaries link Arteries with Veins they exchange materials between the blood and other body cells the wall of a capillary is only one cell thick The exchange of materials between the blood and the body can only occur through capillaries

  6. Arteries • The blood vessels that allow blood to flow from the heart to the capillaries • Thick-walled • Epithelial tissue is wrapped in thick layers of smooth muscle and connective tissue • Allows the artery to constrict (become more narrow) and dilate (relax)

  7. Arteries (continued) • Blood in the arteries is under pressure to help ensure it flows only in one direction - away from the heart and toward the capillaries • As the arteries get further away from the heart, they branch into smaller and smaller vessels, eventually narrowing so much that blood flows into capillaries

  8. The ARTERY Arteries carry blood away from the heart. the elastic fibres allow the artery to stretch under pressure the thick muscle can contract to push the blood along. thick muscle and elastic fibres

  9. Veins • The blood vessels that allow blood to flow to the heart • Epithelial tissue surrounded by smooth muscle and connective tissue • Thinner muscle layer than the arteries • Blood is under very little pressure because the force that pushes it through comes from skeletal muscles tissue, where many veins are found

  10. Veins (continued) • Most veins have valves that allow the blood to flow ONLY toward the heart

  11. The VEIN Veins carry blood towards the heart. Veins have valves which act to stop the blood from going in the wrong direction thin muscle and elastic fibres Body muscles surround the veins so that when they contract to move the body, they also squeeze the veins and push the blood along the vessel.

  12. The CONNECTION A collection of capillaries is known as a capillary bed. artery vein capillaries body cell

  13. Pathway • The overall flow of blood is from the heart to tissues throughout the body • Your body contains about 5 liters of blood • It takes about 1 minute for all that blood to make a complete circuit throughout the body • Increased activity causes the blood to circulate more quickly in order to keep your cells supplied with the necessary oxygen and nutrients

  14. Lungs Body cells Our circulatory system is a double circulatory system. This means it has two parts parts. the right side of the system deals with deoxygenated blood. the left side of the system deals with oxygenated blood.

  15. The Heart • Pumps blood and dissolves substances around the body in tubes called blood vessels.

  16. Two Circuits of Blood Flow • 1) Pulmonary Circuit: carries oxygen-depleted blood from the heart to the lungs and oxygen-rich blood back to the heart • 2) Systemic Circuit: carries oxygen-rich blood from the heart to the rest of the body and oxygen depleted blood back to the heart.

  17. Pulmonary Circuit • Pulmonary Circuit: transports oxygen-poor blood from the right ventricle to the lungs where blood picks up a new blood supply, then it returns the oxygen-rich blood to the left atrium.

  18. Systemic Circuit • Oxygen-rich blood leaves the left side of the heart through the aorta and flows through branching arteries to the capillaries, where the oxygen diffuses out of the blood and carbon dioxide diffuses in. That oxygen-depleted blood returns to the right side of the heart through the veins.

  19. Anatomy of the Heart • Located between your lungs • A sac, called the pericardium, encloses the heart • Four chambers: • left and right atria (thin walls) • left and right ventricles (muscular walls)

  20. The Heart This is a vein. It brings blood from the body, except the lungs. These are arteries. They carry blood away from the heart. 2 atria Coronary arteries, the hearts own blood supply 2 ventricles The heart has four chambers now lets look inside the heart

  21. The Heart Artery to Lungs Artery to Head and Body Vein from Head and Body Vein from Lungs Right Atrium Left Atrium valve valve Left Ventricle Right Ventricle

  22. blood from the lungs blood from the body The heart beat begins when the heart muscles relax and blood flows into the atria. How does the Heart work? STEP ONE

  23. The atria then contract and the valves open to allow blood into the ventricles. How does the Heart work? STEP TWO

  24. The valves close to stop blood • flowing backwards. • The ventricles contract forcing • the blood to leave the heart. • At the same time, the atria are • relaxing and once again filling with • blood. How does the Heart work? STEP THREE The cycle then repeats itself.

  25. Pathway of Blood • Oxygen-rich blood from the lungs gathers in the left atrium and is pumped into the left ventricle. • Blood is pumped from the left ventricle through the aorta to the rest of the body to deliver oxygen and nutrients. • Oxygen-depleted blood returns to the right atrium through veins. • That blood is pumped into the right ventricle, which pumps it to the lungs through the pulmonary arteries. • Once that blood become oxygenated it returns to the left atrium via the pulmonary veins. • Flaps of tissue known as valves prevent blood from flowing backward.

  26. Valves • Valves are located • Between the atria and ventricles (atrioventricular valves) • Between the ventricles and arteries leading from the heart (pulmonary valve and aortic valve) • “Lub Dupp” Heart Sound • “lub”: atrioventricular valve is closing • “dupp”: pulmonary and aortic valves close

  27. Regulation of Heartbeat • Pacemaker: a specific region in the right atrium of your heart that sets the rate at which your heart contracts. • Generate electrical impulses that spread rapidly over the walls of both atria, causing them to contract • AV node: region of the heart that receive the impulses sent from the pacemaker • Spreads the electrical impulses to the ventricle, causing them to contract and send blood to the rest of the body

  28. Blood Pressure • Systolic pressure: (1st number) the highest recorded pressure in an artery when ventricles contract (systole) • Diastolic pressure: (2nd number) the lowest recorded pressure in an artery, during the relaxation phase of the heartbeat (diastole) • ~120/70 is the average blood pressure for a healthy young adult.

  29. BLOOD • Transports oxygen, water, and nutrients to cells. • Distributes hormones through the body • Removes waste products from the tissues and delivers them to the excretory system • Helps fight infection and heal wounds

  30. BLOOD (continued) • 55% of the volume of blood is plasma • 90% of plasma is water • 10% is salts, proteins, other transported substances • 45% of the volume of blood is mostly red blood cells • Also known as erythrocytes • Carry oxygen from the lungs to all of the tissues in the body • 1 drop of blood contains 5 million red blood cells • Each blood cell contains 250 million molecules of hemoglobin (protein that temporarily stores oxygen for delivery to the cells)

  31. BLOOD (continued) • Red Blood Cells (continued) • Produced in bone marrow at the rate of 2 million/second • As they mature they lose their nuclei and mitochondria resulting in their shape: flat disk that curves inward in the middle on the top and bottom • White Blood Cells (leukocytes) • Have nuclei and mitochondria • Responsible for fighting infection and preventing the growth of cancer • 4,000-11,000 white blood cells in a drop of blood • This number increases when infection invades your body • Active most in the interstitial fluid, outside the blood vessels

  32. Clotting • Platelets • Small fragments of blood cells that originate in the bone marrow • 250,000 - 500,000 in a drop of blood • Adhere to the site of a damaged blood vessel and break apart and release clotting factors • Clotting factors make other platelets sticky and activate reactions that result in the formation of fibrin • Fibrin traps red blood cells and eventually forms a patch that stretches over torn tissue and the patch dries into a scab.

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