Cellular Respiration

Glucose + Oxygen = Water + Carbon dioxide + Energy

• Respiration is the process of releasing energy from food for cells to use
• Energy is used for movement, growth, warmth etc.
• It takes place in the mitochondria
• Muscle cells have the most mitochondria because they are most active
• Fat cells have te least mitochondria because they aren't very active

Spirometer: Used to measure the amount of air that enters of leaves the lungs

Arteries: Carry blood AWAY from the heart

Veins: Carry blood TOWARDS the heart

During exercise:

• Heart and breathing rate increases, arteries to muscles dilate
• More oxygen in red blood cells, increased blood flow to muscles
• More oxygen and glucose to muscles, carbon dioxide removed from muscles
• More respiration
• Muscles contract faster

Muscle action:

• Muscles contract by sliding muscle fibres across each other  so the muscle becomes shorter
• Glucose is stored in the muscles as glycogen, which is quickly converted back to glucose when needed
• Glycogen is a carbohydrate

• Respiration without using oxygen

Glucose = Lactic acid + energy

Oxygen Debt:

• Lactic acid is a toxin which builds up in the muscle and causes pain and fatigue
• It is broken down using oxygen, after exercise has stopped

Lactic acid + oxygen = carbon dioxide + water

• The amount of oxygen needed is called the oxygen debt

It takes longer for an unfit person to pay off their oxygen debt becuase their heart/ lungs are weaker so take more pumps to pump the blood all around the body