Functions of blood

• Transport

  • Carries oxygen, nutrients and hormones to cells

  • Carries waste back from them

    • Water

    • CO2

• Defence

  • Destroys bacteria

  • Destroys blood clots

• Controls body temperature

  • 37 degree

Composition of blood

• Plasma

  • Liquid of blood

  • Transports and carries

• Red blood cells

  • Red: haemoglobin

  • Carries oxygen

  • no nucleus

• Platelets

  • Clots blood

  • no nucleus

• White blood cells

  • Fights infections

  • Makes anti-bodies or engulfs the infection

  • Nucleus

Blood vessels

• Artery: carries blood away from the heart

  • Thick wall

  • Small lumen

  • High pressure

  • No valves

  • Goes away from heart

  • High in O2

• Veins: carries blood to the heart

  • Thin wall

  • Big lumen

  • Low pressure

  • Valves

  • Goes to heart

  • Low in O2

• Capilaries: links arteries to veins

  • Very tiny wall

  • Tiny lumen

  • Low pressure

  • No valves

  • Artery to vein

Heart

• The heart is a pump

• Cardiac: to do with heart

Pulse

• Pressure of blood in arteries

• 72 bpm

Can be effected by:

• Age

• Diet

• Gender

• Stress

• Exersise

Why does the pulse increase with exercise

• Exercise needs energy

• More respiration

• More toxic Co2 made

• Pump blood faster to get rid of the Co2

• More O2 and food is brought to the cells for respiration