Physiology of the Circulatory System PDF

Physiology of the Circulatory System Physiology Dept. Fac. of Health Sciences Istanbul Atlas University Istanbul Oct. 2024  Introduction Circulatory system is a transport system. Contributes to body defenses and the coagulatio...

Physiology of the Circulatory System Physiology Dept. Fac. of Health Sciences Istanbul Atlas University Istanbul Oct. 2024  Introduction Circulatory system is a transport system. Contributes to body defenses and the coagulation process and controls body temperature.  Components of cardiovascular system Blood : transport medium Blood vessels: Arteries- Veins - Capillaries Heart : circulates blood through vessels A hollow, muscular organ Comprises Cardiac muscle Simultaneous contraction due to depolarizing at the same time Automaticity Blood vessel White blood cell Red blood cell platelet Plasma  Functions of Blood Transportation: the blood transports dissolved gases, nutrients, hormones and metabolic wastes. Protection: the blood restricts fluid losses through damaged vessels. Platelets in the blood and clotting proteins minimize blood loss when a blood vessel is damaged , and against foreign substances Regulation Blood regulates the pH and electrolyte composition of the interstitial fluids. Blood regulates body temperature.  Blood and Its composition Blood, a type of connective tissue, is a complex mixture of cells, chemicals, and fluid. Blood transports substances throughout the body, and helps to maintain a stable internal environment. The blood includes red blood cells, white blood cells, platelets (formed elements) and plasma. Composition of Blood  Blood Plasma ❑ Straw-colored, sticky fluid portion of blood ▪ Approximately 90% water Contains: Ions : Na and Cl ions Nutrients : sugars, amino acids, lipids, cholesterol, vitamins and trace elements Three main proteins : Albumin (60%), globulin (35%), fibrinogen (4%) Dissolved Gasses : including O2 and CO2 Waste Products : other protein wastes such as urea and bilirubin Composition of Whole Blood  Formed Elements Blood cells Erythrocytes, leukocytes, and platelets Summary of Formed Elements Hematopoiesis  Red Blood cell (RBC) Erythrocytes (RBCs) are the most abundant type of blood cell (99%) Structure Biconcave, anucleate 8 m in dia. Components Hemoglobin Lipids, ATP, carbonic anhydrase Function: Transport of oxygen and carbon dioxide majority of CO2 transported as HCO3- pH homeostasis carbonic anhydrase: CO2 + H2O → HCO3- + H+ ❖RBC’s normally bend to pass through small capillaries ❖are destroyed in spleen ❖Phagocytic WBC’s “clear the debris”  Hematocrit Percentage of the concentration of red blood cells in blood Men: 5 million cells/mm3 Women: 4.5 million cells/mm3  Regulation of red blood cells The total number of red blood cells remains relatively constant due to a negative feedback mechanism utilizing the hormone erythropoietin, which is released from the kidneys and liver in response to the detection of low oxygen levels.  Cont. Dietary Factors Affecting Red Blood Cell Production ; Vitamins B12 and folic acid are needed for DNA synthesis, so they are necessary for the reproduction of all body cells, especially in hematopoietic tissue. Iron is needed for hemoglobin synthesis.  RBC Disease Anaemia refers to a reduction of haemoglobin or red cell concentration in the blood. Polycythemia : excess of erythrocytes; Usually caused by cancer, tissue hypoxia, dehydration; however, naturally occurs at high elevations  White Blood Cells Type Of White Blood % By Volume Of WBC Description Function Cells Neutrophils 60 – 70 % Nucleus has many Phagocytize and destory interconnected lobes; blue bacteria; most numerous granules WBC Eosinophils 2–4% Nucleus has bilobed nuclei; Play a role in ending allergic red or yellow granules reactions containing digestive enzymes Basophils