Cardiovascular System


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Cardiovascular System

  2. 2. THE HEART <ul><li>The central organ of the cardiovascular system is the heart </li></ul><ul><li>The heart is a hollow, muscular organ that contracts at regular intervals, forcing blood through the circulatory system </li></ul><ul><li>Is cone-shaped about the size of a fist, and is located in the thoracic cavity between the lungs directly behind the sternum BREASTBONE) </li></ul>
  3. 3. Heart made up of three layers <ul><li>1. epithelial tissue- outer and inner layers </li></ul><ul><li>2.myocardium –middle layer(CARDIAC MUSCLE TISSUE) </li></ul><ul><li>MITOCHONDRIA -powerhouse of the cell </li></ul>
  4. 4. HOW THE HEART WORKS <ul><li>The heart can be thought of as two pumps sitting side by side. The human Heart with a right atrium and right ventricle as well as a left atrium and a left ventricle. </li></ul><ul><li>The right side of the heart pumps blood from the body into the lungs where oxygen poor blood(Deoxygenated,usually shown in blue) Gives up carbon dioxide and picks up oxygen. </li></ul>
  5. 5. <ul><li>The left side of the heart pumps oxygen rich blood(Oxygenated usually shown in red) from the lungs to the rest of the body except the lungs. </li></ul><ul><li>PERICARDIUM – Heart is enclosed by protective membrane sac and is surrounds the heart and secrete a fluid that reduces friction as the heart beats. </li></ul>
  6. 6. FOUR CHAMBERS OF THE HEART <ul><li>Upper Chambers – Right and Left Atrium – receives blood coming into the heart. </li></ul><ul><li>Lower Chambers - Right and Left Ventricle receive blood out to the heart </li></ul><ul><li>SEPTUM – dividing the right and left sides of the heart. Septum prevents the mixing of oxygen-poor and oxygen-rich blood </li></ul>
  7. 7. THE RIGHT SIDE OF THE HEART <ul><li>Vena cava – oxygen-poor blood from the body enters the right side of the heart through two large blood vessel. </li></ul><ul><li>Superior Vena Cava – brings blood from the lower part of the body to the heart. </li></ul><ul><li>Inferior Vena Cava – brings blood from the lower tract of the body to the heart. </li></ul><ul><li>Both vena cava empty into the right atrium. </li></ul>
  8. 8. <ul><li>ATRIOVENTRICULAR VALVE – When the heart contracts blood is squuezed from the right atrium into the right ventricle through flaps of tissue. And prevents blood from flowing into the right atrium </li></ul><ul><li>TRICUSPID VALVE – the valve that separates the right atrium and ventricle </li></ul><ul><li>Purpose: prevent blood from the right ventricle to the right atrium when the heart ventricles contracts. </li></ul>
  9. 9. Purposes of all Valves <ul><li>Prevent backflow of blood </li></ul><ul><li>Ensure that blood flows in only one direction. </li></ul><ul><li>Remember: </li></ul><ul><li>When the heart contracts a second time,blood in the right ventricle is sent through a semilunar valve known as the pulmonary valve into the pulmonary artery to the lungs.These are the only arteries to carry oxygen –poor the base of the pulmonary arteries is a valve(Pulmonary Valve) That prevents blood from travelling back into the right ventricle. </li></ul>
  10. 10. The Left side of the Heart <ul><li>Oxygen rich blood leaves the lungs and returns to the heart by way of blood vessels called the pulmonary veins.these are the only veins to carry oxygen –rich blood. </li></ul><ul><li>Returning blood enters the left atrium,it passes through flaps of tissue called a atrioventricullar valve to the left ventricle. </li></ul>
  11. 11. <ul><li>The valve that separates the left atrium and ventricle is called the Mitral Valve or Bicuspid Valve. </li></ul><ul><li>From the left ventricle blood is pumped through a semilunar valve called the aortic valve into the aorta artery that carries it to every part of the body expet the lungs. </li></ul><ul><li>At the base of the Aorta is a valve (AORTIC VALVE) prevents blood from flowing back into the left ventricle. </li></ul>
  12. 12. THE HEARTBEAT (cardiac cycle ) <ul><li>The cardiac cycle is the sequence of events in one heartbeat ,in its simplex form the cardiac cylce is the simultaneous contraction of the two atria followed a fraction of a second latter by simultaneous contraction of the two ventricles. </li></ul><ul><li>The heart consists of muscle cells that contracts in waves.When the first group is stimulated, they in turn stimulate neighboring cells.Those cells stimulate more cells.This chain reaction continues until all cels contract.The wave of activity spreads in such a way that the atria and ventricles contracts in a teady rhythm. </li></ul>
  13. 13. TWO PHASES OF HEART <ul><li>PHASE I –SYSTOLE – is the term of contraction occurs when the ventricles contract ,closing the AV valves and opening the SL valves to pump blood into two major vessels leaving the heart,. </li></ul><ul><li>PHASE II –DIASTOLE – is the term for relaxation,occurs when the ventricles relax,allowing the back pressure of the blood to closed SL Valves and opening AV Valves. </li></ul>
  14. 14. Cardiac Cycles: <ul><li>Also creates the heart sounds,each heartbeat produces two sounds often called lubb-dup,that can be heard with a stethoscope. </li></ul><ul><li>The first sound the loudest and the longest is caused by ventricular systole ( Contraction ) closing the AV Valves. </li></ul><ul><li>The second sound is caused by the closure of the Aortic and Pulmonary Valve. </li></ul>
  15. 15. <ul><li>If any of the valves do not close properly an extra sound called heart murmur heard. </li></ul><ul><li>The heart is a single muscle does not contract in a single motion. The contraction spreads over the heart like a wave. </li></ul><ul><li>The wave begins a small bundle of specialized heart muscles cells embedded in the right atrium called the Sinoatrial node (SA) </li></ul><ul><li>The SA node is the natural PACEMAKER of the heart. </li></ul>
  16. 16. <ul><li>When the impulse initiated by the SA Node reaches another special area of the heart known as the ATRIOVENTRICULAR (AV) Node. The AV node is located in the septum between the right and left ventricles.The AV relays the electrical impulse to the muscle cells that make up the ventricles.The ventricles contracts almost simultaneously a fraction of a second after the atria completing one full heartbeat. </li></ul>
  17. 17. <ul><li>These contactions causes the chambers to squezze the blood,pushing it in the proper direction along its path. </li></ul><ul><li>The autonomic nervous system does influence heart rate.The sympathetic nervous system increases heart rate and the parasympathetic nervous system decreases it. </li></ul>
  18. 18. BLOOD VESSELS (arteries,veins,capillaries) <ul><li>Circulatory is a closed system bec the blood contained within either the heart or blood vessels at all times.after the blood leaves the heart,it is pumped through a network of blood vessels to different parts of the body </li></ul><ul><li>THREE LAYERS OF TISSUE 1.epithelial tissue –inner layer </li></ul><ul><li>2.smooth muscle tissue –middle layer </li></ul><ul><li>3.connective layer –outer layer </li></ul>
  19. 19. ARTERIES <ul><li>Carry blood from the heart to capillaries and the rest of the body. </li></ul><ul><li>Walls are thicker than those of veins </li></ul><ul><li>The smooth muscles cells and elastic fibers made up the walls help make arteries tough and flexible.this enables arteries to withstand the high pressure of blood as it is pumped from the heart.the force that blood exerts on the walls of blood vessels is known as blood pressure. </li></ul>
  20. 20. *- <ul><li>Arterioles branch into networks of very small blood vessels called CAPILLARIES. </li></ul><ul><li>-it is the thin-walled(ONE –CELL IN THICKNESS) that the real work of the circulatory system is done. </li></ul><ul><li>Forces of diffusion drive co2 and waste products from the tissue into the capillaries. </li></ul><ul><li>Capillaries are extremely narrow:blood cells moving through them must pass in single file. </li></ul>
  21. 21. <ul><li>VEINS </li></ul><ul><li>- Smallest vein are called VENULES. – are like arteries,veins are lined with smooth muscle.vein walls are thinner and less elastic than arteries.Veins though are more flexible and are able to strech out readily. </li></ul>
  22. 22. PATTERNS OF CIRCULATION <ul><li>Blood moves throgh the body in a continous pathway of which there are two major paths: THE PULMONARY AND SYSTEMIC CIRCULATION </li></ul><ul><li>PULMONARY CIRCULATION carries blood between the heart and the lungs.the circulation begins at the right ventricle and ends at the left atrium. </li></ul>
  23. 23. <ul><li>Oxygen-Poor blood is pumped out of the right ventricle of the heart into the lungs through the pulmonary arteries.These are the only arteries in the body to carry deoxygenated blood. </li></ul><ul><li>Blood returns to the heart through the pulmonary veins,the only veins to carry oxygen rich blood. </li></ul>
  24. 24. <ul><li>The lungs are the only organs directly connected to both chambers of the heart. </li></ul><ul><li>SYSTEMIC CIRCULATION </li></ul><ul><li>- starts at the left ventricle and ends at the atrium ,carries blood to the rest of the body. </li></ul><ul><li>Systemic circulation supplies each major organ with blood, including the heart </li></ul>
  25. 25. Systemic System <ul><li>THREE SUBSYSTEMS: </li></ul><ul><li>Coronary Circulation – supplies blood to the heart. </li></ul><ul><li>Renal Circulation – supplies blood to the kidneys. </li></ul><ul><li>Hepatic Portal Circulation – Nutrients are picked up by capillaries in the small intestines and are transporte to the liver.Excess nutrients are stored in the live for future needs.The liver receives oxygenated blood from a large artery that branches of the aorta. </li></ul>
  26. 26. BLOOD PRESSURE <ul><li>Blood moves through our circulation system because it is under pressure and caused by contraction of the heart and by muscles that sorrounds blood vessels. </li></ul><ul><li>A measure of force that blood exerts against a vessel wall . </li></ul><ul><li>Maintained by two ways: </li></ul><ul><li>1.The nervous system which can speed up or slow down the heart rate. </li></ul><ul><li>2.The kidneys – which regulate blood pressure by the amount of fluid in our blood. </li></ul><ul><li>When our pressure is too high,kidneys remove water from blood, lowering the total amount of fluid in the circulatory system. </li></ul>
  27. 27. <ul><li>Both high and low blood pressure can cause our bodies problems. </li></ul><ul><li>Blood pressure is usually measured in the artery supplying the upper arm to measure blood pressure. </li></ul><ul><li>SYSTOLIC PRESSURE – pressure of the blood when it leaves the ventricles. Normal pressure is about 120 mm Hg for males and 110 mm Hg for females. </li></ul>
  28. 28. <ul><li>DIASTOLIC PRESSURE – or the pressure of the blood is sufficient to keep arteries open constantly even with the ventricles relax. Normal pressure is about 80 mm Hg for males and 70 mm Hg for females. </li></ul><ul><li>YOUR BLOOD PRESSURE IS GIVEN TO AS THE SYSTOLIC NUMBER OVER THE DIASTOLIC NUMBER. </li></ul>