blood gcse
Post on 15-Jan-2015
95 Views
Preview:
DESCRIPTION
TRANSCRIPT
10:45
Red blood cells
• Carry oxygen from lungs to body tissue.• There are 5 000 000 in 1mm3 of blood. • They are adapted in the following ways: (1) Size – thick diameter but thin width. They
just fit through a capillary but the surface to volume ratio is large so they can absorb a lot of oxygen.
10:45
Red blood cells
(2) Shape – they are concave discs – this give greater surface area.
(3) No nucleus – leaves more room for haemoglobin – also no mitochondria or ribosomes.
(4) Haemoglobin – this is a protein that carries oxygen becoming oxyhaemoglobin.
10:45
White blood cells
• Defend against diseases.• They ingest bacteria and viruses.• They produce antibodies.
10:45
Human blood under microscope
10:45
Platelets
• Platelets are small cells that allow blood to clot.
• This stops bleeding and prevent bacteria from entering the body.
10:45
Plasma
• This is the straw coloured liquid in the blood.• Over 90% of plasma is water.• This dissolves: (1) food – amino acids and glucose (2) cholesterol – from the liver (3) hormones – from glands (4) antibodies (5) water – to kidneys (6) waste products like carbon dioxide and lactic acid
10:45
Plasma
top related