Veterinary Physiology Lecture 2 PDF

Lecture 02 … Unit I  Veterinary Physiology (Blood, Cardiovascular, Nervous and Muscular Systems) Dr. S. V. Bharucha Physiology of Bl...

Lecture 02 … Unit I  Veterinary Physiology (Blood, Cardiovascular, Nervous and Muscular Systems) Dr. S. V. Bharucha Physiology of Blood An Introduction Copyright © 2023, Dr. S. V. Bharucha Blood Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Overview of blood syllabus  Composition & general functions of blood, blood cells, plasma and serum, anticoagulants, specific gravity, platelets  Erythrocytes, number, shape, size, composition, specific gravity, erythrocyte sedimentation rate, haematocrit and haemolysis, erythropoeisis and its regulations  Life span and fate or erythrocytes, haemoglobin, chemical structure, synthesis and estimation and anemia  Physiological functions, derivatives of haemoglobin and absorption spectra, anaemia Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Overview of blood syllabus  Leucocytes, classification, origin, properties, differential count, role of lymphocytes in immunity  Plasma composition, plasma proteins, origin and function  Coagulation of blood  Reticuloendothelial (RE) system and blood groups Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Fluid systems of the body  Two main fluid systems in the body  blood  lymph  Blood & lymphatic systems are intertwined thr’out the body  responsible for transporting various substances and agents  Essential functions of a living cell depend on  use of O2 and other metabolic fuels  CO2 and essential metabolites elimination  Early embryonic life  cells receive their necessary nutrients by diffusion Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Fluid systems of the body  As cell multiplication continues  diffusion distance   innermost cells would die if not for a distribution system  that transports the needed nutrients, and  the waste materials  Complex masses of cells forming the animal body depend on diffusion of these substances from or into the blood cells and blood plasma through thin – walled capillaries  Distribution is provided by the cardiovascular system (CVS)  and the transport medium is blood Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Fluid systems of the body  Metabolic activity of body organs can be assessed by its capillary blood supply  Blood  pumped out of heart into capillaries via a diffuse organized branching of the arterial system  returns to the heart by a communicating venous network Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Anatomy and physiology of blood  Blood is an important component of the circulatory system  Anatomically and functionally, blood is a connective tissue  Amount of blood is expressed in terms of percentage of body weight Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Composition of blood  Blood is the body’s fluid connective tissue  It is composed of liquid plasma and formed elements  Formed elements include:  erythrocytes / red blood cells (RBCs)  leucocytes / white blood cells (WBCs)  thrombocytes / platelets Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai  Major components of blood Liquid phase and formed elements Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Blood A specialized type of connective fluid whose matrix fluid known as plasma and has formed elements such as erythrocytes, leucocytes and thrombocytes which remain suspended in it Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Composition of blood – matrix fluid – plasma  Plasma, which makes up 55% of the total volume of blood, is a straw – coloured liquid containing water and solids  Plasma solids include organic substances such as antibodies, hormones, vitamins, enzymes, proteins (AAs), fat (FAs), carbohydrates (glucose / blood sugar) and inorganic salts like Na, K, Ca, Mg, Cl, HCO3, etc.  It also contains many chemicals that help form the blood clots necessary to stop bleeding  More than 92% of plasma is water Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Composition of blood – plasma Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Composition of blood – formed elements  Cellular portion of blood is composed of erythrocytes, leucocytes and thrombocytes  A blood cell, also called a haematopoietic cell, haemocyte, or haematocyte, is a cell produced through haematopoiesis and found mainly in the blood Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Formed elements – erythrocytes  Erythrocytes (RBCs) are flattened, doubly concave cells about 7 µm in diameter  Carry O2 associated in the cell's Hb  Erythrocytes number is so large that blood appears red, even though it contains components other than the erythrocytes  Continuously manufactured in red marrow of long bones, ribs, skull, and vertebrae  They are small, ranging between 4 – 9 million cells / cu mm of blood, and have 200 million Hb molecules / cell Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Red blood cells – erythrocytes  Make up almost 45 % of the blood volume  Shape – biconcave disc with large surface area  Mature erythrocytes lack a nucleus (except in poultry)  Can change shape  Contains haemoglobin  No organelles Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Red blood cells – erythrocytes  Lifespan  120 days  Destroyed in liver and spleen  Iron from Hb is recovered and reused by red bone marrow  Liver degrades the haeme units and secretes them as pigment in the bile, responsible for the colour of faeces  Each second two million erythrocytesare produced to replace those taken out of circulation Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Formed elements – leucocytes  WBCs / leucocytes are larger than erythrocytes, have a nucleus and lack Hb  WBC squeeze through pores in the capillaries and fight infectious diseases in interstitial areas  Some types of leucocytes can live for several months out in the tissue, but other may live for only hours or days  They are made from stem cells in bone marrow  WBCs are less than 1% of the blood's volume Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai White blood cells – leucocytes  They function in the cellular immune response  Mobile units of body’s defense system:  “seek and destroy” function  destroy invading microorganisms  destroy abnormal cells (i.e: cancer cells)  phagocytosis (clean up cellular debris)  assist in injury repair Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai White blood cells – leucocytes  Leucocytes are classified into two subcategories:  Agranulocytes:  Granulocytes:  Lymphocytes  Neutrophils  Monocytes  Eosinophils, and  Basophils  Each WBC has a specific function Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai White blood cells – leucocytes  Neutrophils  enter the tissue fluid by squeezing thr’ capillary walls  phagocytose foreign substances  Macrophages  release leucocytic growth factors, causing an  in the leucocytes Macrophages at work Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai White blood cells – leucocytes  Lymphocytes fight infection  T – cells attack cells containing viruses  B – cells produce antibodies  Macrophages phagocytised antigen – antibody complexes  Neutrophils, monocytes and macrophages are collectively known as phagocytes  Lymphocytes are also called immunocytes Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai White blood cells – leucocytes Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Platelets – Thrombocytes  Coagulate, form plug, prevent blood loss  Formed by fragmentation from megakaryoctyes Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Platelets – Thrombocytes  Development  megakaryocytes shed small cytoplasmic fragments  each fragment has plasma membrane  Anatomy  2 – 4 µm diameter with many granules  250,000 – 400,000 / mm3  no nucleus, disc shaped Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Platelets – Thrombocytes  Physiology  Short life span (5 – 9 days) before being removed by the liver and spleen  Platelets function in the clotting mechanism by forming a temporary plug that helps seal breaks in blood vessels  Granules contain regulatory factors which serve several important functions in:  coagulation  inflammation  immune defenses Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Platelets – Thrombocytes  Granules contain serotonin, Ca++, enzymes, ADP, and platelet derived growth factor (PDGF)  Providing correct proteins (clotting factors) has been a common method of treating haemophiliacs  It has also led to HIV transmission due to the use of transfusions and use of contaminated blood products  Platelets not involved in clotting are kept inactive by nitric oxide (NO) and a prostaglandin called prostacyclin (PgI2)  A haemophiliac's blood cannot clot  Platelets here are stained purple Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Plasma vs Serum Include:  Albumin (60%)  Globulins (36%) (Antibodies & transport proteins)  Clotting Proteins (4%)  Enzymes & Hormones Include:  Albumin (60%)  Globulins (36%) (Antibodies & transport proteins)  Clotting Proteins (4%)  Enzymes & Hormones Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Plasma vs Serum  Plasma is the top layer obtained when blood is combined with an anticoagulant and then made to stand  Serum is the top layer when no anticoagulant is used and then made to stand  Serum = Plasma – Fibrin (clotting factors) Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Anticoagulants  An anticoagulant is a substance that prevents coagulation; i.e. it stops blood from clotting  A group of pharmaceuticals called anticoagulants can be used in vivo as a medication for thrombotic disorders  Some chemical compounds are used in medical equipment, such as test tubes, blood transfusion bags and renal dialysis equipment  heparin (mucoprotein, stops thrombin)  EDTA  sodium citrate  coumarin drugs (dicumarol, warfarin)  recombinant TPA (tissue plasminogen activator) Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Anticoagulants Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Anticoagulants  Laboratory instruments, test tubes, blood transfusion bags, and medical and surgical equipment will get clogged up and become non operational if blood is allowed to clot  Heparin is a biological substance, made from pig intestines  it works by activating antithrombin III, which blocks thrombin from clotting blood  heparin can be used in vivo (by injection), and also in vitro to prevent blood or plasma clotting in or on medical devices  vaccutainer brand test tubes containing heparin are usually coloured green Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Anticoagulants  Apart from heparin, most of these chemicals work by binding calcium ions, preventing the coagulation proteins from using them  EDTA is denoted by mauve / purple caps on vaccutainer brand test tubes  it strongly &irreversibly binds calcium  is in a powdered form Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Anticoagulants  Sodium Citrate vaccutainer  blue  it is in liquid form in the tube and is used for coagulation tests, as well as in blood transfusion bags  it gets rid of the calcium, but not as strongly as EDTA  correct proportion of this anticoagulant to blood is crucial because of the dilution  Oxalate has a mechanism similar to that of citrate  it is the anticoagulant used in fluoride (grey top) tubes Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Haematocrit  Percent of formed elements  normal hematocrit is around 45%, depending on:  species  age  gender  test method, etc. Hematocrit Dr. (Ms.) S. V. Bharucha, Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai Components of Whole Blood Plasma (55% of whole blood) Buffy coat: leucocytes and platelets (