Gas exchange Systems Flashcards
(25 cards)
What is gas exchange?
The process of oxygen entering the body and carbon dioxide leaving the body.
Where does gas exchange occur in humans?
In the alveoli of the lungs.
What are alveoli?
Tiny air sacs in the lungs where gas exchange takes place.
How are alveoli adapted for gas exchange?
Large surface area, thin walls, moist surface, good blood supply.
Why do alveoli have thin walls?
To allow rapid diffusion of gases across the membrane.
Why do alveoli have a large surface area?
To maximise the amount of gas exchange that can occur.
What is the pathway of air into the lungs?
Nose/mouth → trachea → bronchi → bronchioles → alveoli.
What is the trachea?
The main airway leading from the throat to the lungs (windpipe).
What are the bronchi?
The two main branches of the trachea leading to each lung.
What are bronchioles?
Smaller branches of the bronchi that lead to alveoli.
What supports the trachea and bronchi?
Rings of cartilage that keep them open.
What lines the airways?
Ciliated epithelial cells and mucus-producing cells.
What is the function of mucus in the airways?
To trap dust, bacteria, and other particles.
What is the function of cilia in the airways?
To sweep mucus and trapped particles up and out of the lungs.
How does smoking affect the airways?
Damages cilia, increases mucus production, causes inflammation.
What is emphysema?
A lung disease where alveoli are damaged and lose their elasticity.
What is asthma?
A condition where airways become inflamed and narrow.
What muscles are involved in breathing?
Diaphragm and intercostal muscles (between ribs).
What happens during inspiration (breathing in)?
Diaphragm contracts and flattens, ribs move up and out, chest volume increases.
What happens during expiration (breathing out)?
Diaphragm relaxes and curves up, ribs move down and in, chest volume decreases.
What controls breathing rate?
The medulla in the brain stem.
How does the brain control breathing?
It monitors carbon dioxide levels and adjusts breathing rate accordingly.
What is the composition of inhaled air?
21% oxygen, 0.04% carbon dioxide, 79% nitrogen.
What is the composition of exhaled air?
16% oxygen, 4% carbon dioxide, 79% nitrogen.
