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CARDIOVASCULAR SYSTEM

  1. 1. CARDIOVASULAR SYSTEM Presented by Dr. SINDHU. K, MVSc SCHOLAR, Dept of VPT, COVAS, POOKODE
  2. 2. CARDIO VASCULAR SYSTEM CV physiology is study of the functions of the heart, the blood vessels and the blood 3 main divisions of CVS THE DISTRIBUTION SYSTEM - Heart, arteries, arterioles. THE PERFUSION SYSTEM – arteries, arterioles, capillaries. THE COLLECTING SYSTEM – venules, veins, heart.
  3. 3. MAJOR COMPONENTS OF THE CVS • RESISTANCE COMPONENT – the arterial system • CAPACITANCE COMPONENT – the venous system • CARDIAC OUTPUT • PRE LOAD • AFTER LOAD • HYDROSTATIC PRESSURE • CHRONOTROPIC EFFECT ( heart rate ) • IONOTROPIC EFFECT ( contractility )
  4. 4. IMPORTANCE OF CVS 1. The primary function of CVS is TRANSPORT ( metabolic substrates) 2. CONDUCTS chemical messengers ( harmones ) 3. ELECTROLYTE BALANCE & tissue homogeneity 4. Maintains HEMOSTASIS 5. Helps to maintain COLLOIDAL OSMOTIC PRESSURE
  5. 5. WILLIAM HARVEY ( 1628 ) • Father of cardiovascular physiology • Set forth the first proof that HEART PROPELS THE BLOOD THROUGH BLOOD VESSELS IN A CIRCULATORY PATTERNS • Before HARVEY’S proposal it was believed that blood flows in TIDAL FASHION similar to respiratory system • However the circularity of the cardiovascular system makes it difficult • No clear ideas about tissue supply demand & supply of blood to pheriphery
  6. 6. PHYSICAL CHARACTERISTIC OF CIRCULATION • SYSTEMIC CIRCULATION • Blood supplied to all parts of the body • Also called GREATER / PERIPHERAL CIRCULATION • PULMONARY CIRCULATION • Blood transported to LUNGS only
  7. 7. PERFUSION PRESSURE >< TRANSMURAL PRESSURE • PERFUSION PRESSURE • Difference in the pressure between the two points in a blood vessel • Causes the blood to flow through blood vessel • TRANSMURAL PRESSURE • Difference between the blood pressure inside a blood vessel & the fluid pressure outside the vessel • Causes blood to flow out of a vessel if you poked a hole in the vessel wall
  8. 8. MODE OF TRANSPORT OF BLOOD FLOW • BULK FLOW • Rapid over long distances • Transport requires ENERGY which is the HYDRO STATIC PRESSURE DIFFERENCE • DIFFUSION • Primary mechanism by which dissolved substances move across the wall of blood vessels from the blood stream into the interstitial fluids or vice versa • ENERGY source is CONCENTRATION GRADIENT
  9. 9. ORIGIN OF BLOOD CELLS
  10. 10. 10 Blood (4.8%) (95.1%) (0.1%) Plasma Hormones MonocytesBasophilsEosinophilsNeutrophils (54–62%) (1–3%) (<1%) (3–9%) (25–33%) GlobulinsAlbumins (92%) (7%) N2 O2 CO2 Platelets Red blood cells Proteins Nutrients Gases 45% 55% WastesWaterWhite blood cells Electrolytes Vitamins Lymphocytes Fibrinogen Formed elements Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  11. 11. THE ORIGIN OF BLOOD CELLS 11 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. (b) Megakaryoblast Myeloid stem cell Megakaryocyte Monocyte Macrophage T lymphocyte B lymphocyte Plasma cell Hematopoietic stem cell Myeloblast Progranulocyte Erythroblast Normoblast Reticulocyte Erythrocyte Incirculatingblood Neutrophil Basophil Granulocytes Eosinophil Proerythroblast Monoblast Promonocyte Prolymphocyte Prolymphocyte Inredbonemarrow Agranulocytes (a) Lymphoid stem cell Lymphoblast B cell precursor Lymphoblast T cell precursor Neutrophilic myelocyte Basophilic myelocyte Eosinophilic myelocyte Eosinophilic band cell Basophilic band cell Neutrophilic band cell Thrombocytes (platelets) Activatedintissues (somecells)
  12. 12. RED BLOOD CELL PRODUCTION AND ITS CONTROL 12 • Low blood oxygen causes the kidneys and the liver to release erythropoietin (EPO) which stimulates RBC production • This is a negative feedback mechanism Within a few days many new blood cells appear in the circulating blood Low blood oxygen Liver Kidney Erythropoietin Red bone marrow + – Bloodstream Stimulation Inhibition Release into bloodstream Increased oxygen- carrying capacity Increased number of red blood cells Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  13. 13. 13 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Centrifuged Blood Sample Peripheral Blood Smear Liquid (plasma) “Buffy coat” white blood cells and platelets) Red blood cells Red blood cells Platelets White blood cells
  14. 14. 14 (b) (a) a: © The McGraw-Hill Companies, Inc./Al Telser, photographer :b © Ed Reschke Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  15. 15. DESTRUCTION OF RED BLOOD CELLS 15
  16. 16. 16 Bilirubin Bone Blood Liver Globin + Heme 3 2 1 Absorption 4 5 Macrophage Hemoglobin Iron + Biliverdin 8 6 7 Bile Red bone marrow Red blood cells produced Red blood cells circulate in bloodstream for about 120 days Old red blood cells Blood transports absorbed nutrients Nutrients from food Vitamin B12 Folic acid Iron Small intestine Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  17. 17. ERYTHROPOIESIS
  18. 18. TYPES OF WHITE BLOOD CELLS 18 • White blood cells: • Are leukocytes • Protect against disease • WBC hormones are interleukins and colony-stimulating factors which stimulate development • There are five types of WBCs in two categories: • Granulocytes • Neutrophils • Eosinophils • Basophils • Agranulocytes • Lymphocytes • Monocytes
  19. 19. NEUTROPHILS 19 • Light purple granules in acid-base (neutral) stain • Lobed nucleus • Other names • Segs • Polymorphonuclear leukocyte • Bands (young neutrophils) • First to arrive at infections • Phagocytic (What is this?) • 54% - 62% of leukocytes • Elevated in bacterial infections (Why?) © Ed Reschke Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  20. 20. EOSINOPHILS 20 • Deep red granules in acid stain • Bi-lobed nucleus • Moderate allergic reactions • Defend against parasitic worm infestations • 1% - 3% of leukocytes • Elevated in parasitic worm infections and allergic reactions © Ed Reschke Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  21. 21. BASOPHILS 21 • Deep blue granules in basic stain • Release histamine •Release heparin Less than 1% of leukocytes • Similar to Eosinophils in size and shape of nuclei © Ed Reschke Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  22. 22. MONOCYTES 22 • Largest of all blood cells • Spherical, kidney-shaped, oval or lobed nuclei • May leave bloodstream to become macrophages • 3% - 9% of leukocytes • Phagocytize bacteria, dead cells, and other debris © R. Kessel/Visuals Unlimited Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  23. 23. LYMPHOCYTES 23 • Slightly larger than RBC • Large spherical nucleus surrounded by thin rim of cytoplasm • T cells and B cells •Both important in immunity • B cells produce antibodies • 25% - 33% of leukocytes © Ed Reschke Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  24. 24. FUNCTIONS OF WHITE BLOOD CELLS 24 • WBCs protect against infection • These leukocytes can squeeze between the cells of a capillary wall and enter the tissue space outside the blood vessel (called diapedesis) Blood capillary Leukocyte Connective tissue Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  25. 25. 25 Epidermis Dermis Blood vessels 1 Splinter punctures epidermis 5 6 2 3 4 Injured cells release histamine, causing blood vessels to dilate Bacteria multiply Bacteria are introduced into the dermis Neutrophils destroy bacteria by phagocytosis Neutrophils move through blood vessel walls and migrate toward bacteria Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  26. 26. 26
  27. 27. 27
  28. 28. 14.3: BLOOD PLASMA 28 • Blood plasma is: • Straw colored • The liquid portion of blood • 55% of blood volume • 92% water • Function includes transporting nutrients, gases, and vitamins • Helps regulate fluid and electrolyte balance and maintain pH
  29. 29. PLASMA PROTEINS 29 • These are the most abundant dissolved substances (solutes) in plasma
  30. 30. GASES AND NUTRIENTS 30 • The most important blood gases: • Oxygen • Carbon dioxide • Plasma nutrients include: • Amino acids • Simple sugars • Nucleotides • Lipids • Fats (triglycerides) • Phospholipids • Cholesterol
  31. 31. NONPROTEIN NITROGENOUS SUBSTANCES 31 • These are molecules containing nitrogen but are not proteins • In plasma they include: • Urea – product of protein catabolism; about 50% of nonprotein nitrogenous substances • Uric acid – product of nucleic acid catabolism • Amino acids – product of protein catabolism • Creatine – stores phosphates •Creatinine – product of creatine metabolism • BUN – blood urea nitrogen; indicates health of kidney
  32. 32. PLASMA ELECTROLYTES 32 • Plasma contains a variety of these ions called electrolytes • They are absorbed from the intestine or released as by- products of cellular metabolism They include: • Sodium (most abundant with chloride) • Potassium • Calcium • Magnesium • Chloride (most abundant with sodium) • Bicarbonate • Phosphate • Sulfate
  33. 33. 14.4: HEMOSTASIS 33 • Hemostasis refers to the stoppage of bleeding • Actions that limit or prevent blood loss include: • Blood vessel spasm • Platelet plug formation • Blood coagulation
  34. 34. 34
  35. 35. 35
  36. 36. PLATELETS • Platelets are cell fragments produced from megakaryocytes. • Blood normally contains 150,000 to 400,000 per microliter (µl). If this value should drop much below 20,000/µl, there is a danger of uncontrolled bleeding. This is because of the essential role of platelets • in maintaining the integrity of the adherens junctions that provide a tight seal between the endothelial cells that line the blood vessels; • in forming a clot where blood vessels have been broken
  37. 37. PLATELETS
  38. 38. PLATELET ADHESION
  39. 39. PLATELET PLUG FORMATION 39 • Platelet plug formation • Triggered by exposure of platelets to collagen • Platelets adhere to rough surface to form a plug Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Endothelial lining Collagen fiber Platelet Red blood cell 1 2 3 4 Break in vessel wall Blood escaping through break Platelet plug helps control blood loss Platelets adhere to each othe , to end of broken vessel, and to exposed collagen
  40. 40. 40 © SPL/Photo Researchers, Inc. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  41. 41. EXTRINSIC CLOTTING MECHANISM 41 • Extrinsic clotting mechanism • Chemical outside of blood vessel triggers blood coagulation • Triggered by tissue thromboplastin (factor III) (not found in blood) • A number of events occur that includes factor VII, factor X, factor V, factor IV, and factor II (prothrombin) • Triggered when blood contacts damaged blood vessel walls or tissues • This is an example of a positive feedback mechanism
  42. 42. INTRINSIC CLOTTING MECHANISM 42 • Intrinsic clotting mechanism • Chemical inside blood triggers blood coagulation • Triggered by Hageman factor XII (found inside blood) • Factor XII activates factor XI which activates IX which joins with factor VIII to activate factor X • Triggered when blood contacts a foreign surface
  43. 43. INTRINSIC & EXTRINSIC PATH WAYS
  44. 44. FATE OF BLOOD CLOTS 44 • After a blood clot forms it retracts and pulls the edges of a broken blood vessel together while squeezing the fluid serum from the clot • Platelet-derived growth factor stimulates smooth muscle cells and fibroblasts to repair damaged blood vessel walls • Plasmin digests the blood clots • A thrombus is an abnormal blood clot • An embolus is a blood clot moving through the blood vessels
  45. 45. Antithrombin III As its name suggests, this plasma protein (a serpin) inhibits the formation of thrombin. It does so by binding to and thus inactivating:  prothrombin  factor 9  factor 10 Heparin is a mixture of polysaccharides that bind to antithrombin III, inducing an allosteric change that greatly enhances its inhibition of thrombin synthesis. Some surgical patients, especially those receiving hip or heart valve replacements, and people at risk of ischemic stroke (clots in the brain), are given heparin.
  46. 46. Protein C With its many clot-promoting activities, it is probably no accident that thrombin sits at the center of the control mechanism.  Excess thrombin binds to cell-surface receptors called thrombomodulin.  The resulting complex activates a plasma protein called Protein C and its cofactor Protein S.  Together these inhibit further thrombin formation o directly — by inactivating Factor 5 and o indirectly — by inactivating Factor 8. Vitamin K Vitamin K is a cofactor needed for the synthesis (in the liver) of  factors 2 (prothrombin), 7, 9, and 10  proteins C and S So a deficiency of Vitamin K predisposes to bleeding. Conversely, blocking the action of vitamin K helps to prevent inappropriate clotting.
  47. 47. FIBRINOLYSIS
  48. 48. BLEEDING DISORDERS • A deficiency of a clotting factor can lead to uncontrolled bleeding. • The deficiency may arise because • not enough of the factor is produced or • a mvon Willebrand disease (the most common) • hemophilia A for factor 8 deficiency • hemophilia B for factor 9 deficiencyutant version of the factor fails to perform properly. • hemophilia C for factor 11 deficiency
  49. 49. SCREENING TEST • OSPT/PT-One Stage Prothrombin Time • Detects abnormality in plasma level of F5, F7, F10 • Also the abnormality in prothrombin activity or fibrinogen concentration • Detects LIVER DYSFUNCTION • APTT/PTT-Activated Partial Thromboplastin Time • Detects the abnormality in plasma levels of F12, F10, F9, F8,PROTHROMBIN, FIBRINOGEN • Detects the PLATELET COUNTS
  50. 50. THANK YOU • Physiology of cardiovascular system • Origin of blood cells and circulation mechanisms • Hemostasis • Coagulation cascade • Screening tests

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