Blood Physiology
OPTOMETRY · SEMESTER 1 Blood Physiology Human Anatomy and Physiology START READING NOTES Contents of This Topic INTROD CONT … INTRODUCTION INTRODUCTION cont … COMPONENTS OF BLOOD COMPONENTS OF BLOOD CONT … BLOOD PLASMA Plasma proteins Plasma proteins CONT … Albumins Globulins BLOOD CELLS FUNCTIONS OF BLOOD CLASSIFICATION OF BLOOD CELLS RED BLOOD CELLS RED BLOOD CELLS CONT.. erythroPOIESIS SITES FOR ERYTHROPOIESIS erythroPOIESIS CONT… MATURATION OF ERYTHROCYTE Differentiation of Formed Elements from Stem Cells HAEMATOPIOESIS Hemopoietic Growth Factors Haemoglobin Control of erythropoiesis Control of erythropoiesis CONT … function of erythrocytes function of erythrocytes CONT … Destruction of erythrocytes Destruction of erythrocytes CONT .. Blood groups Blood groups CONT … The ABO system Leukocytes (white blood cells) Granulocytes (polymorphonuclear leukocytes) Neutrophils Neutrophils CONT … Eosinophils Eosinophils CONT … Basophils Agranulocytes Monocytes The monocyte–macrophage system The monocyte–macrophage system CONT .. Lymphocytes Examples of antigens include: Platelets (thrombocytes) Platelets (thrombocytes) CONT … Haemostasis 1 Vasoconstriction 2 Platelet plug formation 3 Coagulation (blood clotting) CLOTTING FACTORS CLOTTING FACTORS CONT … CLOTTING PATHWAYS BLOOD PHYSIOLOGY PART I INTROD CONT … BLOOD: Is a liquid connective tissue or viscous fluid that: Circulates in a virtually “CLOSED” system of blood vessels Blood, a connective tissue, that is composed of plasma and formed elements. INTRODUCTION Blood is a specialized body fluid that circulates through the cardiovascular system of humans and other vertebrates. It serves multiple critical functions, including the delivery of necessary substances such as oxygen and nutrients to cells, as well as the removal of metabolic waste products. INTRODUCTION cont … It circulates continually around the body, allowing constant communication between tissues distant from each other. Blood makes up about 7% of body weight (about 5.6 litres in a 70 kg man). This proportion is less in women and considerably greater in children, gradually decreasing until the adult level is reached. Blood in the blood vessels is always in motion because of the pumping action of the heart. INTRODUCTION cont … The continual flow maintains a fairly constant environment for body cells. Blood volume and the concentration of its many constituents are kept within narrow limits by homeostatic mechanisms. COMPONENTS OF BLOOD Composition of blood is divided into two aspects, the formed elements part and fluid part, namely; Blood Plasma (Fluid part) – occupies 55% of blood Blood Cells (Formed Element part) – occupies 45% of blood COMPONENTS OF BLOOD CONT … Blood is composed of a clear, straw-coloured, watery fluid called plasma in which several different types of blood cell are suspended. Plasma normally constitutes 55% of the volume of blood. The remaining 45% is accounted for by the cellular fraction of blood. The two fractions of blood, blood cells and plasma, can be separated by centrifugation (spinning) or by gravity when blood is allowed to stand. Because the cells are heavier than plasma, they sink to the bottom of any sample. BLOOD PLASMA Blood plasma is the liquid component of blood that constitutes approximately 55% of its total volume. It is a light amber-colored fluid that serves several critical functions in the body. Plasma is primarily composed of water (about 92%), with the remaining content consisting of plasma proteins, electrolytes, hormones, nutrients, and waste products. Plasma proteins Plasma proteins, which make up about 7% of plasma, are normally retained within the blood, because they are too big to escape through the capillary pores into the tissues. They are largely responsible for creating the osmotic pressure of blood, which keeps plasma fluid within the circulation. If plasma protein levels fall, because of either reduced production or loss from the blood vessels, osmotic pressure is also reduced, and fluid moves into the tissues (oedema) and body cavities. Plasma proteins CONT … Plasma Proteins include albumin, immunoglobulins, fibrinogen Plasma viscosity (thickness) is due to plasma proteins, mainly albumin and fibrinogen. Plasma proteins, with the exception of immunoglobulins, are formed in the liver. Albumins These are the most abundant plasma proteins (about 60% of total) and their main function is to maintain normal plasma osmotic pressure. Albumins also act as carrier molecules for free fatty acids, some drugs and steroid hormones. Globulins Their main functions are: as antibodies (immunoglobulins), which are complex proteins produced by lymphocytes that play an important part in immunity. They bind to, and neutralise, foreign materials (antigens) such as microorganisms. Transportation of some hormones and mineral salts, e.g. thyroglobulin carries the hormone thyroxineand transferrin carries the mineral iron inhibition of some proteolytic enzymes, e.g. α2 macroglobulin inhibits trypsin activity. BLOOD CELLS Blood cells are specialized cells produced through a process known as hematopoiesis, primarily found in the blood. They play crucial roles in various physiological functions, including oxygen transport, immune defense, and blood clotting. There are three main types of blood cells: Red blood cells (erythrocytes) White blood cells (leukocytes) Platelets (thrombocytes). SUMMARY OF BLOOD CONSTITUENTS FUNCTIONS OF BLOOD The major functions of blod includes; Oxygen Transport Nutrient Distribution Waste Removal Hormone Transport Temperature Regulation pH Balance Fluid Balance Immune Response Clotting Mechanism CLASSIFICATION OF BLOOD CELLS Blood cells can be classified into three main types: red blood cells, white blood cells, and platelets. Each type has distinct functions and characteristics. RED BLOOD CELLS Red blood cells are the most abundant type of blood cell, accounting for approximately 40 to 45 percent of the blood’s volume. Their primary function is to transport oxygen from the lungs to the body’s tissues and return carbon dioxide from the tissues back to the lungs for exhalation. Red blood cells contain hemoglobin, a protein that binds oxygen and gives blood its red color. They are characterized by their biconcave disk shape, which allows for flexibility as they navigate through various sizes of blood vessels. RED BLOOD CELLS CONT.. Red blood cells are biconcave discs; they have no nucleus, and their diameter is about 7 micrometres. Their main function is in gas transport, mainly of oxygen, but they also carry some carbon dioxide. Their characteristic shape is suited to their purpose; the biconcavity increases their surface area for gas