💦 Blood and tissue fluid

Blood components
Tissue fluid

Blood components


Blood is fun! Blood is to body as the Thames is to London, although I sure hope slightly cleaner…


Blood is roughly split into the plasma and blood cells including erythrocytes and leucocytes (neutrophils, eosinophils, monocytes, lymphocytes). Plasma is the solution that blood cells are found in, and as such acts as their extracellular matrix. For skin cells for example, the extracellular matrix is formed of collagen, so it’s different to have it essentially a liquid like plasma. Plasma is a water solution containing proteins, sugars, clotting factors (as well as platelets involved in clotting), hormones, electrolytes, carbon dioxide and oxygen.



Erythrocytes are red blood cells/RBC (and also the most common blood cells) carrying haemoglobin around the body. Haemoglobin can bind and release oxygen and is central to aerobic respiration.



Leucocytes of varying types are white blood cells/WBC, colourless, and act in defence against infection and disease.


There are many types of white blood cell. Neutrophils are the most common and, alongside monocytes, digest invading cells of bacteria and fungi by engulfing them in a process called phagocytosis. The invader is engulfed…