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Human Circulatory System

Human Circulatory System. BILL. The Circulatory System. Blood Flow Heart Blood Pressure Blood Flow Lymphatic System Respiratory System. The Heart – draw a diagram of the heart from you book on page 158 – 15 minutes. The Heart. About the size of your fist

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Human Circulatory System

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  1. Human Circulatory System

  2. BILL

  3. The Circulatory System Blood Flow Heart Blood Pressure Blood Flow Lymphatic System Respiratory System

  4. The Heart – draw a diagram of the heart from you book on page 158 – 15 minutes

  5. The Heart • About the size of your fist • Pump that forces blood through vessels with regular contractions • Pericardium – outside tough protective covering of the heart

  6. The Heart • 4 chambers of the heart • Atria (2) – upper chambers, thin walled chambers that collect blood from moving in from veins • Ventricles (2) – lower chambers, thick muscular walls that build up enough pressure to pump blood to lungs/body

  7. The Heart • Septum – separates L and R side of the heart and prevents mixing of oxygen rich (L side) and oxygen poor (R side) blood

  8. The Heart • Blood flow in heart controlled by 4 valves • Atrioventricular Valves (2) – allow blood from atria to ventricles • R Side – Tricuspid Valve (3 flaps) • L Side – Bicuspid Valve (2 flaps) or Mitral Valve • Semilunar Valves (2) – allow blood to move from ventricle to pulmonary artery, or from ventricle to aorta

  9. The Heart

  10. Blood Vessels • Pulmonary Arteries – carries blood from right ventricle to lungs • Pulmonary Veins – carries blood from lungs to left atria • Aorta – carries blood from left ventricle to the rest of the body • Superior/Inferior vena cava – veins that carry blood from the body back to the right atria

  11. Blood Flow through Heart

  12. The Heart – Blood Flow • Pair of side-by-side pumps each consisting of two chambers • Two possible routes • Pulmonary circulation – blood flow from right side of heart to lungs and back • Systemic Circulation – blood flow from left side of heart to body cells and back

  13. Blood Flow through Heart

  14. Pulmonary Circulation • Oxygen poor blood collects in right atrium, and flows through right AV valve into the right ventricle • Once ventricle full, in begins to contract, causing: • Right AV valve closes to prevent backflow • Blood pressure increases inside right ventricle, opening right semilunar valve • Blood is pumped through pulmonary artery to lungs to gain oxygen and back to heart into left atrium

  15. Blood Flow through Heart

  16. Systemic Circulation • Blood flows from lungs to the let atrium through the left AV valve into ventricle • Once ventricle fills, it begins to contract causing: • Closure of left AV valve to prevent backflow • Increase in blood pressure inside ventricle, opening left semilunar valve • Blood pumps into aorta, leaving the heart and traveling to the body

  17. Circulation • Right and left sides of heart act in unison • Both atria contract at same time, both ventricles contract at same time • Closing of the valves causes “lub dub” sound of heart beat

  18. Heart Beat and Pressure

  19. Heart Rate – “lub-dub” sound of heart valve opening and closing (can be heard with a stethoscope) • Myogenic Muscle Contraction – spontaneous contraction/relaxation of cardiac muscle without nervous system control • Diastole – relaxed heart • Systole – contraction of the heart

  20. Sinoatrial (SA) Node (“Pacemaker”) Specialized group of cells in R atria that produce small electrical current , signaling for the atria to contract and keeps contracting (recorded on an ECG – Electrocardiogram)

  21. Atrioventricular Node (AV node) • Specialized mass of tissue that receives signals from SA node and sends the signal for ventricular contraction • Occurs roughy 0.1 seconds after signal is received

  22. Heart Rate Control • During Exercise, heart rate increases due to increased demand for oxygen/removal of CO2 • As CO2 levels rise, area in brain called the Medulla senses increase and sends a signal to SA node through the cranial nerve, called a cardiac nerve, to increase in HR • HR increases the rate of contractions

  23. Heart Rate Control • As CO2 levels decrease after exercise, Medulla senses decrease and sends a signal to SA node through the cranial nerve, called vagus nerve, to decrease HR • SA node returns to normal pace of contractions

  24. Heart Rate Control - Chemicals • Heart rate is also influenced by chemicals • During periods of excitement/stress, adrenal glands secrete adrenaline • Causes SA node to fire more frequently and increase heart rate

  25. Blood Pressure • Pulse – alternate expansion (high pressure) and relaxation (low pressure) of an artery

  26. Blood Pressure • Normal Resting Blood Pressure – 120/80 (systolic/diastolic) • When ventricles contract – high blood volume into arteries (high pressure) • When heart is relaxed, less volume in arteries so pressure decreses

  27. BILL • Explain how the heart beats? (5 marks) • SA node fires (electrical) signal throughout walls of atria to begin cycle; causing atria to undergo systole; SA signal reaches atrioventricular node; which spreads signal throughout; causing ventricles to undergo systole; atrioventricular valves slap shut; causing "lub" sound; after ventricles are emptied semilunar valves close; causing "dub" sound; atrioventricular valves open; ventricles begin diastole and start filling; all four chambers are in diastole and filling;when atria filled and ventricles 70% filled cycle has ended;

  28. Arteries, Capillaries, and Veins

  29. Closed System with Three Types of Blood Vessels • Arteries • Veins • Capillaries

  30. Arteries – carry blood Away from the heart to organs and tissues • Thick, muscular, elastic walls • Blood at High Pressure as it travels through artery • Branch off into smaller arterioles (the smallest arteries) in tissues and organs

  31. Capillaries – connect arteries to veins • So small (1 cell thick), red blood cells must go through single file • Dissolved nutrients, wastes, oxygen, etc exchanged between blood and body cells as blood flows through capillaries

  32. Veins – return blood to the heart from the body organs and tissues • Thin and slightly elastic for large diameters because of low pressure • Flap-like valves in veins allow blood to flow in one direction only (toward the heart) • Venules – smallest veins

  33. Varicose Veins Vein walls become stretched and valves do not work properly causing blood to build up in vein

  34. Blood - liquid tissue that transport, regulates, and protects

  35. Plasma – liquid part of blood (nonliving) • Transports nutrients, wastes, Hormones, etc • Mostly water (90%)

  36. Red Blood Cells (RBCs) - Erythrocytes • Red in color – hemoglobin • Transport dissolved substances (oxygen, carbon dioxide, nutrients, wastes, etc) • No nucleus

  37. Red Blood Cells • Smaller than white blood cells • More numerous than white blood cells (2-5 million per mm3 of blood) • Made by bone marrow and live for about 120 days

  38. Red Blood Cell Disorders • Anemia – too few RBCs or insufficient amount of hemoglobin causing body to not receive enough oxygen • Sickle Cell Anemia – caused by abnormal shaped hemoglobin

  39. White Blood Cells (WBCs) - Leukocytes • AKA phagocytes and lymphocytes • Colorless • Helps fight infection and protect the body from disease causing organisms • Move on their own like amoebas (pseudopods) and through circulatory system

  40. White Blood Cells • Have a nucleus • Larger than RBCs • Less numerous than RBCs (5,000-10,000) – you have more WBCs in your body when you have an infection and less when you are healthy

  41. White Blood Cells • Made by bone marrow and lymphatic tissue • Leukemia – cancer of cells that make WBCs

  42. Platelets • Help to clot blood and begin the healing process • Blood cell fragments (250,000-500,000) • Live for 7 days

  43. Blood Clotting – platelets stick together to damaged/torn area and seal the “leak” • If wound is more serious  clotting process takes over • Platelets release thromboplastin (enzyme) • Thromboplastin converts prothrombin (plasma protein) into thrombin • Thrombin converts fibrinoogen into fibrin • Fibrin forms a network of strands that trap RBCs and platelets to form clot • Once the healing is complete, plasmin (enzyme) dissolves the fibrin clot

  44. Blood Clot

  45. Clotting Problems • Hemophilia – hereditary disease with inability to clot blood • Clotting when not needed  heart attack or stroke

  46. Blood – liquid tissue that transport, regulates, and protects • Transports – oxygen, carbon dioxide, nutrients, wastes, etc • Regulates – absorbs heat, maintains pH and water balance, etc • Protects – defense against pathogens

  47. BILL • Distinguish between the following: Red Blood Cells, White Blood Cells, Platelets • RBCs – small cells with no nucleus, composed of protein hemoglobin, transport dissolved nutrients • WBC – larger cells with a nucleus, help fight infections in the body and protects body from infectious diseases • Platelets – blood cell fragments help to clot blood and begin healing process

  48. Lymphatic System

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