Blood is a major part of the human body. It is required for most functions of cells. Blood is comprised of 3 main sections: Plasma, Thrombocytes, red blood cell (Erythrocytes), White Blood Cells (Leukocytes).
Plasma contains many molecules ranging from clotting factors, dissolved proteins and even carbon dioxide through respiration. Plasma is extremely important in the transport of metabolites such as ATP an glucose around the body. It also can contain waste molecules such as urea and lactic acid.
Erythrocytes are used in gas exchange using the protein Haemoglobin (Hb). The most distinct characteristic of the Erythrocytes is their unique biconcave shape. To be more specific, erythrocytes are flat and disc-shaped with indentations in the middle of both sides. This contribute to the ease of carrying and transporting oxygen across the whole blood stream. Erythrocytes are also able to demonstrate their membrane flexibility by being able to squeeze through the very tiny and narrow blood capillaries.
Leukocytes are used to defend the body against pathogens via phagocytosis or antibody production. There are many leukocytes differing in their mechanisms and appearance (granular/agranular): lymphocytes, monocytes, basophils and eosinophils
- ↑ Sherwood (2010) Human Physiology (From Cells to Systems), 7th edition, Canada : BROOKS/COLE CENGAGE Learning. page 392-4