University of Ishik Faculty of Dentistry 2 nd stage Lec. Physiology Abdulqadir Kh. Hamad The Cardiovascular System: The Blood

Blood Liquid connective tissue 3 general functions 1. Transportation Gases, nutrients, hormones, waste products 2. Regulation Regulation of pH and osmosis osmotic pressure Maintain of the body 3. Protection Protection against foreign substances By white blood cells, immune proteins (Antibodies & Compete Protein ) Clot formation prevent bleeding

Components of Blood  Blood plasma – water liquid extracellular matrix 90.5 % -91.5% water, 8.5% solutes (primarily proteins) Hepatocytes synthesize most plasma proteins  Albumins, fibrinogen, antibodies Other solutes include electrolytes, nutrients, enzymes, hormones, gases and waste products  Formed elements – cells and cell fragments Erythrocytes: Erythrocytes: Red blood cells (RBCs) : Leukocytes : Leukocytes : White blood cells (WBCs) Thrombocyte : Thrombocyte : Platelets

Components of Blood 1- Plasma  Liquid part of blood  Blood plasma – water liquid extracellular matrix 91.5% water, 8.5% solutes (primarily proteins) Hepatocytes synthesize most plasma proteins  Albumins, fibrinogen, antibodies Colloid: Liquid containing suspended substances that don’t settle out  Albumin: Important in regulation of water movement between tissues and blood  Globulins: Immune system or transport molecules  Fibrinogen: Responsible for formation of blood clots Other solutes include electrolytes, nutrients, enzymes, hormones, gases and waste products

II. Plasma C. ~2% organic solutes 1. amino acids 2. vitamins 3. hormones 4. lipoproteins D. ~1% inorganic salts E. dissolved gases

Formed Elements of Blood

Formation of Blood Cells Negative feedback systems regulate the total number of RBCs and platelets in circulation Abundance of WBC types based of response to invading pathogens or foreign antigens Red bone marrow primary site Pluripotent stem cells have the ability to develop into many different types of cells

Formation of Blood Cells Stem cells in bone marrow  Reproduce themselves  Proliferate and differentiate Cells enter blood stream through sinusoids Formed elements do not divide once they leave red bone marrow  Exception is lymphocytes

Formation of Blood Cells Pluripotent stem cells produce  Myeloid stem cells Give rise to red blood cells, platelets, monocytes, neutrophils, eosinophils and basophils  Lymphoid stem cells give rise to Lymphocytes Hemopoietic growth factors regulate differentiation and proliferation  Erythropoietin – RBCs  Thrombopoietin – platelets  Colony-stimulating factors (CSFs) and interleukins – WBCs

Red Blood Cells/ Erythrocytes Contain oxygen-carrying protein hemoglobin Production = destruction with at least 2 million new RBCs per second Biconcave disc – increases surface area Strong, flexible plasma membrane Glycolipids in plasma membrane responsible for ABO and Rh blood groups Lack nucleus and other organelles  No mitochondria

19-13 Erythrocytes Structure  Biconcave, anucleate Components  Hemoglobin  Lipids, ATP, carbonic anhydrase Function  Transport oxygen from lungs to tissues and carbon dioxide from tissues to lungs

Hemoglobin  Globin – 4 polypeptide chains  Heme in each of 4 chains  Iron ion can combine reversibly with one oxygen molecule  Also transports 23% of total carbon dioxide Combines with amino acids of globin  Nitric oxide (NO) binds to hemoglobin Releases NO causing vasodilation to improve blood flow and oxygen delivery

Shapes of RBC and Hemoglobin

Red Blood Cells RBC life cycle  Live only about 120 days  Cannot synthesize new components – no nucleus  Ruptured red blood cells removed from circulation and destroyed by fixed phagocytic macrophages in spleen and liver  Breakdown products recycled Globin’s amino acids reused Iron reused Non-iron heme ends as yellow pigment urobilin in urine or brown pigment stercobilin in feces

Formation and Destruction of RBC’s

Red blood cell death and phagocytosis Key: in blood in bile Macrophage in spleen, liver, or red bone marrow 1 Globin Red blood cell death and phagocytosis Key: in blood in bile Macrophage in spleen, liver, or red bone marrow Heme 2 1 Amino acids Reused for protein synthesis Globin Red blood cell death and phagocytosis Key: in blood in bile Macrophage in spleen, liver, or red bone marrow Heme Amino acids Reused for protein synthesis Globin Red blood cell death and phagocytosis Transferrin Fe 3+ Key: in blood in bile Macrophage in spleen, liver, or red bone marrow Heme Amino acids Reused for protein synthesis Globin Red blood cell death and phagocytosis Transferrin Fe 3+ Liver Key: in blood in bile Macrophage in spleen, liver, or red bone marrow Ferritin Heme Amino acids Reused for protein synthesis Globin Red blood cell death and phagocytosis Transferrin Fe 3+ Transferrin Liver Key: in blood in bile Macrophage in spleen, liver, or red bone marrow Ferritin Heme Amino acids Reused for protein synthesis Globin Red blood cell death and phagocytosis Transferrin Fe 3+ Transferrin Liver + Globin + Vitamin B 12 + Erythopoietin Key: in blood in bile Macrophage in spleen, liver, or red bone marrow Ferritin Heme Fe Amino acids Reused for protein synthesis Globin Circulation for about 120 days Red blood cell death and phagocytosis Transferrin Fe 3+ Transferrin Liver + Globin + Vitamin B 12 + Erythopoietin Key: in blood in bile Erythropoiesis in red bone marrow Macrophage in spleen, liver, or red bone marrow Ferritin Heme Fe Amino acids Reused for protein synthesis Globin Circulation for about 120 days Red blood cell death and phagocytosis Transferrin Fe 3+ Transferrin Liver + Globin + Vitamin B 12 + Erythopoietin Key: in blood in bile Erythropoiesis in red bone marrow Macrophage in spleen, liver, or red bone marrow Ferritin Heme Biliverdin Bilirubin Fe Amino acids Reused for protein synthesis Globin Circulation for about 120 days Bilirubin Red blood cell death and phagocytosis Transferrin Fe 3+ Transferrin Liver + Globin + Vitamin B 12 + Erythopoietin Key: in blood in bile Erythropoiesis in red bone marrow Macrophage in spleen, liver, or red bone marrow Ferritin Heme Biliverdin Bilirubin Fe Amino acids Reused for protein synthesis Globin Stercobilin Bilirubin Urobilinogen Feces Small intestine Circulation for about 120 days Bacteria Bilirubin Red blood cell death and phagocytosis Transferrin Fe 3+ Transferrin Liver + Globin + Vitamin B 12 + Erythopoietin Key: in blood in bile Erythropoiesis in red bone marrow Macrophage in spleen, liver, or red bone marrow Ferritin Heme Biliverdin Bilirubin Fe Amino acids Reused for protein synthesis Globin Urine Stercobilin Bilirubin Urobilinogen Feces Small intestine Circulation for about 120 days Bacteria Bilirubin Red blood cell death and phagocytosis Transferrin Fe 3+ Transferrin Liver + Globin + Vitamin B 12 + Erythopoietin Key: in blood in bile Erythropoiesis in red bone marrow Kidney Macrophage in spleen, liver, or red bone marrow Ferritin Urobilin Heme Biliverdin Bilirubin Fe Amino acids Reused for protein synthesis Globin Urine Stercobilin Bilirubin Urobilinogen Feces Large intestine Small intestine Circulation for about 120 days Bacteria Bilirubin Red blood cell death and phagocytosis Transferrin Fe 3+ Transferrin Liver + Globin + Vitamin B 12 + Erythopoietin Key: in blood in bile Erythropoiesis in red bone marrow Kidney Macrophage in spleen, liver, or red bone marrow Ferritin Urobilin Heme Biliverdin Bilirubin Fe

Erythropoiesis  Starts in red bone marrow with proerythroblast  Cell near the end of development ejects nucleus and becomes a reticulocyte  Develop into mature RBC within 1-2 days  Negative feedback balances production with destruction  Controlled condition is amount of oxygen delivery to tissues  Hypoxia stimulates release of erythropoietin

Copyright 2009, John Wiley & Sons, Inc.

19-21 Erythropoiesis Production of red blood cells  Stem cells proerythroblasts early erythroblasts intermediate late reticulocytes Erythropoietin: Hormone to stimulate RBC production

Iron Metabolism: Key to Hemoglobin O 2 Transport

19-23 Hemoglobin Breakdown

Copyright 2009, John Wiley & Sons, Inc.