6.6 Structure of the human gas-exchange surface Flashcards
Why do aerobic organisms require a constant supply of oxygen
To release energy in the form of ATP during respiration
Why is the volume of oxygen that had to be absorbed and the volume of carbon dioxide to be removed so large in mammals
- They are large organisms with a large volume of living cells
- They maintain a high body temperature which is related to them having high metabolic and respiratory rates
Why are lungs located in the body
- Air is not dense enough to support and protect their delicate structure
- The body as a whole would otherwise lose a great deal of water and dry out
What are the lungs supported and protected by
The ribcage
How can ribs be moved
By muscles between them
What are the main parts of the human gas-exchange system
- Lungs
- Trache
- Bronchi
- Bronchioles
- Alveoli
What are the lungs
Lobed structures made up of a series of bronchioles which end in alveoli
What is the trachea
A flexible airway that is supported by cartilage. Cartilage prevents the trachea collapsing as air pressure inside falls
What are the tracheal walls made up of and lined with
Muscle, lined with cliliated epithelium and goblet cells
What are bronchi
Two divisions of the trachea, each leading to one lung.
What do the bronchi produce and what lines them
Mucus to trap dirt particles and they are lined with cilia that move the dirt laden mucus towards the throat
What are the bronchioles
A series of branching divisions of the bronchi. Their walls are made of muscle lined with epithelial cells
What do the muscle of bronchioles allow them to do
Constrict so they can control the flow of air in and out of the alveoli
What are alveoli
Minute air-sacs at the end of bronchioles, they are sized between 100-300 micrometres.
What are between alveoli
Collagen and elastic fibres that allow them to stretch as they fill with air breathing in
