Download The Blood

The Blood
• How many litres of blood
do you have in your body?
• 4-6 L
• Blood has four main
components
– Plasma
– Red blood cells
– White blood cells
– Platelets
Plasma (55%)
• Straw coloured solution
containing
– Water with dissolved salts
(90%)
– Plasma proteins (10%)
– Nutrients, metabolic wastes,
hormones, O2, CO2
• Plasma proteins help
transport vitamins and fight
viral and bacterial infections
Red Blood Cells (41%)
• Carry oxygen (hemoglobin)
• Produced in bone marrow (2 million/second)
• No nuclei
– Life span of ~100 days
– Gives them a flat disk shape
– Increased surface area for O2 molecules
– Flexibility to squeeze through different sized
blood vessels
Sickle Cell Anemia
White Blood Cells (3%)
• Fight infection, parasites, and bacteria
• Can move through blood vessel walls
• Your WBC count increases when you
have an infection
• Pus is WBCs and dead bacteria
• Produced in the bone marrow
• Life span of years
Platelets (1%)
• Help with blood clotting
• Release clotting factors
• Scab forms
Blood Type
Blood Vessels
• Arteries
• Capillaries
• Veins
Arteries:
– Carry blood away from the heart to the body tissues
– Smaller diameter
– High pressure
Capillaries:
– Exchange of nutrients and wastes (diffusion gradient)
– Tiny tubes with large surface area
Veins:
–
–
–
–
Carry blood back to the heart
Larger diameter
Low pressure
Valves allow blood to only flow in one direction