18 March 2019 The functions of blood include: The transportation and distribution of oxygen and nutrients to the tissues and organs in the body; Collection and disposal of waste resulting from the functioning of these organs and tissues; Combatting infections; Regulation of the acid-base balance (pH) and body temperature; The transportation of hormones from the place they are produced to the place they will act. What is blood made up of? Blood consists of various components that help it to perform the functions for which it is responsible. These can be divided into 2 groups: 1. Cells On average, cells represent 45% of the blood and include: Red blood cells; White blood cells; Platelets. Red blood cells, or erythrocytes , are the cells responsible for transporting oxygen and for the red colour of blood . They contain haemoglobin, the protein that binds to oxygen to enable it to be transported in the blood. White blood cells, or leukocytes , are the cells essential for fighting infection and other attacks on the body, and make up part of the immune system. There are 5 types of leukocyte , which can be grouped as follows: Granulocytes (neutrophils, eosinophils and basophils); Agranulocytes (lymphocytes and monocytes). Platelets, or thrombocytes , are the smallest cells in the blood and are responsible for coagulation , which helps control bleeding . What are the characteristics of blood cells? Blood cells are produced in the bone marrow , a spongy substance found in the internal cavities of the bones. For blood cells to be produced correctly, the bone marrow must be healthy and receive the necessary nutrients, which are transported in the blood. All blood cells originate from stem cells , of which there are two types in the bone marrow: Lymphoid; Myeloid. After they are formed, the blood cells are released by the bone marrow into the bloodstream. 2. Plasma The plasma, or liquid fraction of the blood , represents on average 55% of the blood , is yellowish in colour and is made up of: Water (around 92%); Plasma proteins (around 8%); Small amounts of other substances such as: Carbon dioxide; Urea; Lactic acid; Coagulation factors; Antibodies; Sodium; Chlorine. It is also the method used for transporting blood cells . Serum is obtained from plasma by separating the plasma proteins from other proteins involved in coagulation. Did you know that... Every day millions of blood cells are produced ; each type has an average life span lasting from a few hours to more than 100 days. As the number of cells of each type remains relatively constant under normal conditions, millions of blood cells also die every day . This article was written with the support of physicians and other clinical professionals from the Hospital da Luz network . The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
