Answered: Relate the functions of platelets in…

Human Anatomy & Physiology (11th Edition)

11th Edition

ISBN:9780134580999

Author:Elaine N. Marieb, Katja N. Hoehn

Publisher:Elaine N. Marieb, Katja N. Hoehn

Chapter1: The Human Body: An Orientation

Section: Chapter Questions

Problem 1RQ: The correct sequence of levels forming the structural hierarchy is A. (a) organ, organ system,...

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Components of blood

Blood consist of two main components :-

Blood plasma, mainly composed of extracellular liquid matrix. Blood contains about 55% of blood plasma. Blood plasma is 90-92% of water and 8-10% of solutes which are mainly protein in nature. Hepatocytes synthesize most of these plasma proteins, like albumins(50-55% of plasma protein), globulins (35-40%) and fibrinogen (7-10%). fibrinogen is one of the most important clotting factors produced by liver. Blood plasma without clotting factor is known as serum. Globulins provide defense mechanisms against pathogens and maintain blood volume and pressure. Albumins help to maintain the body's osmotic pressure and pH. Along with these proteins blood plasma also consists of some amount of ions, minerals, amino acids, glucose and lipids. Plasma also has hormones, vitamins and nitrogenous wastes like urea and uric acid.
Formed elements, which is mainly composed of three components : erythrocytes (red blood cell, RBC), leukocytes (white blood cell, WBC) and platelets. erythrocytes and leukocytes consist of the whole cell but platelets consist of cell fragments. These formed elements are synthesized in red bone marrow. The process of formation of formed elements of blood is known as hematopoiesis.
a. Red blood cell is a biconcave shape containing oxygen- carrying protein hemoglobin which is responsible for oxygen transport and responsible for the red color of RBC. Mature RBC does not have nucleus and other membrane bound organelles. RBC survives an average of 120 days. Each RBC contains approximately 280 million hemoglobin molecules.
White blood cells (WBC) have nuclei and do not contain hemoglobin molecules. WBC are colorless due to lack of hemoglobin. They are less in number and short lived. WBC are mainly classified into two categories: granulocytes and agranulocytes. Granulocytes have chemical filled cytoplasmic granules or vesicles. Agranulocytes have very little chemical filled cytoplasmic granules which are not visible under microscope due to small size and poor staining. granulocytes are further divided into eosinophil, basophils and neutrophils. eosinophils mainly deals with allergic conditions and internal parasite infestations. Basophils deals with reactions related to inflammations. It stores and synthesizes histamine and heparin. Neutrophils are phagocytic cells destroying foreign particles that enter into the body.
Agranulocytes are divided into lymphocytes and monocytes. lymphocytes are further divided into B-lymphocytes and T-lymphocytes. B-lymphocytes mainly protect the body by producing antibodies against foreign antigen. T- lymphocytes destroyed the antigen presenting cells. Monocytes are differentiated into macrophage which is a phagocytic cell.