Gas exchange Flashcards
1
Q
How are the airways kept clean?
A
- Goblet cells produce mucus
- Mucus traps the dirt/bacteria
- Cilia (cells with hairlike structures) waft the ladened mucus up to the mouth where it is swallowed and destroyed by HCl in the stomach
2
Q
What is ventilation?
A
Movement of air into and out of the lungs
3
Q
Describe the process of breathing in (inhalation)
A
- External intercostal muscles contract
- Ribs move up and out
- Diaphragm contracts and flattens
- Volume inside thorax increases
- Pressure decreases
- Air is sucked into the lungs
4
Q
Describe the process of breathing out
A
- Internal intercostal muscles contract
- Ribs move down and in
- Diaphragm relaxes and become dome shaped
- Volume inside thorax decreases
- Pressure increases
- Air is forced out of the lungs
5
Q
Compare inhaled and exhaled air
A
Inhaled air contains more oxygen and less carbon dioxide than exhaled air
6
Q
How are the alveoli adapted for gas exchange?
A
- Large surface area
- Good blood supply
- Thin walls - short diffusion pathway
- Moist - dissolve gases
7
Q
Describe the effects of smoking on the body
A
- Cilia are paralysed - build up of mucus - smoker’s cough - infection - bronchitis
- Smoke damages alveolar walls - walls break down - decreased surface area for gas exchange -
emphysema - Carcinogens - tumour growth - lung cancer
- Carbon monoxide combines irreversibly with haemoglobin in red blood cells -
Carboxyhaemoglobin - less oxygen transported