Chapter Five Flashcards
The circulatory system transports materials throughout the body
Functions of the blood
- Transport
- Regulation
- Protection
Transport
Transports nutrients and oxygen to the tissues and removes waste such as carbon dioxide
Regulation
Assists in maintaining the body’s pH level and temperature
Protection
- Prevent blood loss if blood vessels are damaged
- Protects the body against pathogens and toxins
Red blood cells
- Life span of 120 days
- No nucleus to save space for carrying oxygen and going through narrow spaces (capillaries)
- Haemoglobin is present to attach to oxygen
White blood cells
- Fights infections and foreign substances by engulfing and destroying them
- Contains a nucleus
-Shape varies to squeeze between cells in tissues
Platelets
Irregular shape to help in clotting blood to stop bleeding
Blood plasma
A clear pale yellow liquid which comprises of 46-63% of the whole blood
What does blood plasma consist of
- Water (92%)
- Dissolved molecules (1%)
- Dissolved plasma proteins (7%)
Oxygen transport
- 3% dissolved in plasma as a solution
- 97% combined with haemoglobin in RBCs
What colour is oxyhaemoglobin
Bright red
Carbon dioxide transport
- 8% dissolved in plasma as a solution
- 22% combined with haemoglobin as carbaminohaemoglobin
- 70% in plasma as bicarbonate ions
Blood clotting steps
- Vasoconstriction
- Platelet plug
- Coagulation
Blood clotting
The events that take place to minimise blood loss and prevent entry of infecting micro organisms
Vasoconstriction
Muscles in the walls of the small arteries that are injured/broken constrict to reduce blood flow and therefore blood loss
Platelet plug
- Walls of arteries are normally smooth but become rough with injury that allow platelets to stick
- Platelets build up at the sight to form a plug
- Reduces blood loss
- Platelets release substances that act as vasoconstrictors and prolong constriction of the damaged vessels
Coagulation
- Complex process involving a large number of chemical substances present in the blood plasma
- Formation of threads occur called fibrin which form mesh that traps blood cells, platelets and plasma
- This mesh with its trapped material holds the clot in position
Clot retraction
- Network of threads become denser and stronger pulling damaged blood vessels together
- As clot retraction occurs, fluid (serum) is squeezed out
- The clot dries forming a scab preventing infection
Common name for Thrombocytes
Platelets
Common name for Leucocytes
White blood cells
Common name for Erythrocytes
Red blood cells
Coagulation is
Blood clotting
Arteries
- Thick walled
- Muscular
- Carry blood away from heart to the organs and tissues
- Oxygenated blood
- No valves
Veins
- Thin walled
- Carry blood back to the heart away from the organs and tissues
- Deoxygenated blood
- Valves