Structure Of Human Gas Exchange System Flashcards
Why is the volume of oxygen absorbed and carbon dioxide removed in mammals large?
- relatively large organisms with a large volume of living cells
- maintain a high body temperature which is related to them having high metabolic and respiratory rates
Why are lungs located inside the body?
- air is not dense enough to protect and support these delicate structures.
- the body would otherwise lose a lot of water and dry out.
How are the lungs protected in the body?
The ribcage which can be moved by the muscles between them.
What are the lungs?
Pair of lobed structures made up of highly branched tubes called bronchioles, which end in tiny air sacs called alveoli.
What is the trachea?
Flexible airway supported by rings of cartilage which prevent the trachea collapsing as air pressure falls. The walls are made up of muscle, lined with ciliated epithelium and goblet cells.
What is the bronchi?
Two divisions of the trachea each leading to one lung. They produce mucus to trap dirt particles and have cilia to move the mucus to the throat. They are also supported by cartilage.
What are the bronchioles?
Series of branching subdivisions of the bronchi. Their walls are made of muscle lined with epithelial cells, allowing them to constrict so they can control flow of air in and out of the alveoli.
What are the alveoli?
Minute air-sacs at the end of bronchioles, Between alveoli are collagen and elastic fibres which allow the alveoli to stretch as they fill with air when breathing in, and spring back during breathing out to expel the carbon dioxide-rich air.
What is the gas-exchange surface of the lung?
The alveolar membrane
