Blood Plasma Serum Tissue Fluids and Lymph 1
Blood Plasma, Serum, Tissue Fluids and Lymph 1. 1. 2 e, f
Learning Objectives e) describe the differences between plasma, serum, tissue fluid and lymph; (f) describe the normal composition of blood plasma;
What is blood? Blood is a specialized transport medium that is also considered a special type of connective tissue. An average adult has 4– 6 litres of blood. Blood has a range of functions such as: l l transport defence thermoregulation maintaining p. H of body fluids.
The composition of blood
Features of erythrocytes What are the specialized features of an erythrocyte? flattened, biconcave disc shape: ensures large surface area to volume ratio for efficient gas exchange diameter (6– 8 µm) larger than capillary diameter: slows blood flow to enable diffusion of oxygen large amount of haemoglobin: for transporting oxygen no nucleus or organelles: maximises space for haemoglobin, so more oxygen can be transported
Serum When the blood clotting protein, fibrinogen, has been removed from the blood plasma, the solution which remains is called serum.
Plasma proteins and blood pressure About 8% of blood plasma consists of plasma proteins, of which about half may be albumins. These are a group of small proteins involved in the transport of other substances (e. g. fatty acids, hormones) and which help regulate the osmotic pressure of blood. The balance between the hydrostatic pressure of blood (‘blood pressure’) and the osmotic pressure of blood is important in the formation of tissue fluid.
Formation of tissue fluid
Lymph Not all tissue fluid returns to the capillaries. The excess drains into the lymphatic system, where it forms lymph. Lymph is a colourless/pale yellow fluid similar to tissue fluid but containing more lipids. lymphatic capillaries The lymphatic system drains into the circulatory system near the vena cava via the thoracic duct.
Task Page 17, answer questions 1, 2 and 3.
Homework
- Slides: 11