B7: Blood Cells

Plasma:

-yellow

-carries:

• carbon dioxide from respiring tissues to lungs
• soluble products of digestion, from gut to cells
• waste products e.g. urea from liver to kidneys, where it's made into urine

Red Blood Cells:

-more numerous than other types

-number count increases in high altitdudes

-picks up oxygen in alveoli and tansports to respiring tissues

-biconcave disc shape = larger surface area = more oxygen diffusing

-no nuclues = more space to carry oxygen

-lots of haemoglobin:

• picks up and reacts with oxygen = oxyhaemoglobin (brighter in colour)
• splits to release oxygen at tissues
• contains iron, less iron in diet = less red blood cells = anaemia

White Blood Cells:

-large nucleus

-defends body against attacking microbes