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Circulatory System

Circulatory System. Honors Biology. Circulatory System. Heart Blood Blood Vessels. Heart Approximately the size of your fist Weighs less than a pound 5 Liters of blood is pumped through 60 000 miles of blood vessels per minute

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Circulatory System

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  1. Circulatory System Honors Biology

  2. Circulatory System • Heart • Blood • Blood Vessels

  3. Heart • Approximately the size of your fist • Weighs less than a pound • 5 Liters of blood is pumped through 60 000 miles of blood vessels per minute • Beats ~100 000 times a day

  4. Heart Covering Pericardium •    Protects and anchors heart •    Prevents overfilling Heart Wall Epicardium - visceral layer of the serous pericardium Myocardium – cardiac muscle layer forming the bulk of the heart Endocardium – lines the heartchambers and continues with endothelial lining of blood vessels

  5. External Heart: Major Vessels of the Heart • Superior & inferior venae cava • Right and left pulmonary veins • Pulmonary trunk (splits into right & left pulmonary arteries) • Ascending aorta (3 branches) – brachiocephalic, carotid, & subclavian arteries

  6. Heart Chambers Atria of the Heart • Atria are the receiving chambers of the heart • Blood enters right atria from superior & inferior venae cava & coronary sinus Blood enters left atria from pulmonary veins Ventricles of the Heart • Ventricles are the discharging chambers • Papillary musclesmark ventricular walls • Interventricular septum separate ventricles Right ventricle pumps blood into the pulmonary trunk Left ventricle pumps blood into the aorta

  7. Pathway of Blood through the Heart and Lungs (Pulmonary & Systemic Circuits) Pulmonary Circuit •     Right atrium  tricuspid valve  right ventricle •     Right ventricle  pulmonary semilunar valve  pulmonary arteries lungs Systemic Circuit •      Lungs  pulmonary veins  left atrium •      Left atrium  bicuspid valve  left ventricle •      Left ventricle  aortic semilunar valve  aorta •      Aorta  systemic circulation

  8. Microscopic Heart Muscle Anatomy •      Cardiac muscle is striated, short, fat, branched, and interconnected •  Intercalated discs anchor cardiac cells together & allow free passage of ions •      Heart muscle behaves as a functional syncytium

  9. Cardiac Cycle Cardiac cycle refers to all events associated with blood flow through the heart The cardiac cycle has two phases: Systole (contraction) Diastole (relaxation)

  10. Cardiac Conduction

  11. Electrocardiography (ECG or EKG) Electrical activity is recorded by electrocardiogram (EKG) P wave corresponds to depolarization of SA node & atria (ATRIAL SYSTOLE) QRS complex corresponds to ventricular depolarization (VENTRICULAR SYSTOLE & ATRIAL DIASTOLE) T wave corresponds to ventricular repolarization (VENTRICULAR DIASTOLE) Atrialrepolarization record is masked by the larger QRS complex

  12. Abnormal ECG Deflection Wave Patterns Sinus Bradycardia Rate = 40-59 b.p.m.

  13. Sinus Tachycardia • Rate = 101-160 b.p.m. • Causes • CHF, hypoxia, pulmonary edema • Increased temperature • Stress or response to pain

  14. Sinus Arrest Causes Myocarditis MI Digitalis toxicity

  15. Atrial Flutter Rate = 250-350 b.p.m. Precipitates CHF

  16. Atrial Fibrillation (afib) Causes COPD CHF

  17. Ventricular Tachycardia (V-tac) Rate = 100-220 b.p.m. • Causes • CAD • Acute MI • Digitalis toxicity • CHF

  18. Ventricular Fibrillation (V-fib) Causes Acute MI

  19. Asystole

  20. Coronary Bypass

  21. The 3 major types of vessels Arteries – carry blood away from the heart Veins – carry blood toward the heart Capillaries – contact tissue cells (Serving cellular needs)

  22. Capillaries ·Very narrow (10 µm diameter, the red blood cells that travel through capillaries are 6 µm in diameter). Capillaries are made of thin endothelial cells (one layer thick)

  23. Hydrostatic & Osmotic Pressures • The high hydrostatic pressure on the arterial side squeezes water and nutrients out of the capillaries. • Water leaving the capillaries builds up the osmotic pressure because the blood components have become more concentrated. • Towards the venal end, water and waste materials are sucked into capillaries by the osmotic pressure.

  24. Varicose veins

  25. What Causes Varicose Veins?

  26. How to treat varicose veins Sclerotherapy Compression Stockings Ablation or Laser treatment (Both use heat)

  27. Blood • Cardiovascular System

  28. Blood Functions 1. Transports • Dissolved gasses • Nutrients • Waste products to lungs and kidneys • Enzymes • Hormones from endocrine organs 2. Regulates • pH • Electrolyte concentration of body fluids • Body temperature 3. Restricts fluid loss 4. Defends pathogens and toxins

  29. Blood Composition 1. Formed elements • Erythrocytes • Leukocytes • Platelets 2. Plasma

  30. Overview of Blood Circulation • Blood leaves the heart via arteries that branch repeatedly until they become capillaries • Oxygen (O2) and nutrients diffuse across capillary walls and enter tissues • Carbon dioxide (CO2) and wastes move from tissues into the blood • Oxygen-deficient blood leaves the capillaries and flows in veins to the heart • This blood flows to the lungs where it releases CO2 and picks up O2 •      The oxygen-rich blood returns to the heart

  31. Blood Physical Characteristics and Volume • Sticky, opaque fluid with a metallic taste •  Color varies from scarlet (oxygen-rich) to dark red (oxygen-poor) •  pH of blood is 7.35–7.45 •  Temperature is 38C, slightly higher than “normal” body temperature •   Blood accounts for approximately 8% of body weight •   Average volume of blood is 5–6 L for males, and 4–5 L for females

  32. Plasma • Plasma accounts for 55 % of the volume of whole blood. • 92% of plasma is water, the rest consists of electrolytes and dissolved organic compounds. Blood plasma contains over 100 solutes, including: •    Proteins – albumin, globulins, clotting proteins, etc… •    Non-protein nitrogenous substances – lactic acid, urea, creatinine •    Organic nutrients – glucose, carbohydrates, amino acids •    Electrolytes – sodium (Na+), potassium (K+), calcium (Ca++), chloride (Cl-), bicarbonate (HCO3-) •    Respiratory gases – oxygen and carbon dioxide

  33. Erythrocytes • Biconcave discs • RBCs have no nuclei or organelles (anucleate) allow for a huge surface area to volume ratio • Hematocrit – % of RBCs out of the total blood volume. (Ave) 46 adult men & 42 adult women. • There are roughly 5 million RBCs in each microliter of blood • Erythrocytes are unable to perform normal maintenance operations and usually degenerate after about 120 days in the circulation.

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