Functions of blood Flashcards
How does blood transport things?
- Transports dissolved materials such as glucose, vitamins and minerals, products of digestion (some can’t be dissolved in water)
- Plasma is 90% water, and so some products including fat have to be carried in the blood bound to lipoproteins.
What is the difference between the two forms of cholesterol? (lipoprotein)
Low-density lipoprotein (LDL) is ‘bad cholesterol’. LDL’s deposit more fat than HDL’s ‘good cholesterol’ along the walls of the arteries.
High-density lipoprotein (HDL’s) do not deposit fats on the artery walls and may even remove harmful deposits.
How are oxygen and carbon dioxide transported?
Transported between the lungs and tissues
Erythrocytes contain haemoglobin, a red iron containing protein. It binds to oxygen forming oxyhaemoglobin, and carries it from the lungs to respiring tissues
How are Erythrocytes adapted for this purpose?
biconcave shape
no nucleus
(increases surface area to volume ratio)
How are hormones carried?
Released by glands and transported into the blood to act on target organs and change the way they function or trigger a response
What is the optimum internal body temperature?
37 degrees
Why is it important to remain at this temperature?
All chemical reactions in our bodies use enzymes, which can become denatured. (No longer work-changes shape)
Blood removes heat and circulates it round the body and heat is a product of when cells respire
How are materials exchanged?
Erythrocytes maintain a diffusion gradient in the capillaries in the lungs.
The concentration of oxygen in the air inside the alveoli is greater than in the blood. (vice versa for CO2).
The steeper the diffusion gradient for each gas the faster the rate of diffusion into (oxygen) or out of (CO2) the blood
A good blood supply maintains this gradient
How is infection prevented?
Leucocytes are involved in immune response
Pathogens that invade the body have antigens on their surface that are recognised as threats by neutrophils and lymphocytes which make antibodies specific to the antigen
Antibodies bind to antigens making them easier to spot by monocytes that engulf them and break pathogens down
Viruses can’t live outside of a cell but lymphocytes recognise cells containing viruses, latch onto such cells and kill them, destroying the virus too.
How does blood clot?
Platelets, when exposed to air, activate a series of reactions called coagulation.
This converts a soluble blood protein (fibrinogen) into insoluble fibrin
This fibrin forms a mesh trapping platelets and erythrocytes forming a clot
The platelets also activate the immune system, reducing the risk of infection
