The mammalian gas exchange system Flashcards
(9 cards)
1
Q
What is the structure of the lungs from largest to smallest?
A
1) Trachea
2) Left and right bronchus
3) Bronchiole
4) Alveoli
2
Q
How are the alveoli adapted for gas exchange?
A
- Large surface area to volume ratio = more O2 into blood and more CO2 out of blood
- Moist to allow gases to dissolve
- Covered with capillaries (which maintains the concentration gradient)
- One cell thick so short diffusion distance
3
Q
How is the lungs adapted for gas exchange?
A
- Large surface area provided by alveoli/capillaries
- Fick’s law = diffusion rate is proportional to the surface area
- Large number of red blood cells
- Concentration gradient maintained by blood flow/ventilation
4
Q
What is lung surfactant?
A
- Phospholipid
- Coats the alveoli
- Prevents the alveoli from collapsing
- Makes breathing easier
5
Q
What are incomplete rings of cartilage?
A
- Prevents the trachea and bronchi from collapsing
- Allows food to be swallowed and moved down the oesophagus
6
Q
What is the result of cystic fibrosis?
A
- Produces thicker mucus
- Blocking airways
- Cilia are unable to move mucus out of lungs
- Reduced flow of O2 to alveoli
- Loss of surface area
- Trapped bacteria may result in more respiratory infections
7
Q
How are the lungs protected?
A
- Produces mucus (which lines the airways) that traps pathogens/bacteria
- Cilia sweep the mucus out of the lungs easily as it’s runny
- Some mucus is swallowed (which is digested by digestive enzymes and the acid in the stomach)
8
Q
How does inhalation work?
A
- Intercoastal muscles and diaphragm contract
- Volume increases and pressure decreases
- Air moves into the lungs
9
Q
How does exhalation work?
A
- Intercoastal muscles and diaphragm relax
- Volume decreases and pressure increases
- Air moves out of the lungs
