What is breathing rate?
The volume of air in each breath
The maximum volume of air that can be breathed in or out
How many breaths are taken per unit time
The rate at which a person uses up oxygen
What features do bronchi have?
Large C-shaped pieces of cartilage
Smooth muscle
Elastic fibres
Goblet cells
Ciliated epithelium
Smaller pieces of cartilage
What features do the trachea have?
What features do alveoli have?
What happens during inspiration?
The intercostal and diaphragm muscles contract
The ribcage moves upward and outwards and the diaphragm flattens
The volume in the thorax increases
The lung pressure decreases
Air flows into the lungs
The intercostal and diaphragm muscles relax
The ribcage moves downwards and inwards and the diaphragm becomes curved
The thorax volume decreases
The air pressure increases
Air is forced out of the lungs
Air always flows from areas of high pressure to areas of low pressure.
When using a spirometer, the total volume of gas in the chamber decreases over time.
What happens during expiration?