Alveoli- Contain collagen, elastic fibres and lined with epithelium. Elastic fibres allow them to stretch and fill with air and spring back to expel CO2.
Bronchi- Cartalidge gets reduced as it gets smaller. Produce musus and have cilia.
Trachea- Supported by rings of cartalidge.
Rib Cage- Supports and protects the lungs.
Bronchioles- Branching sub-divisions of bronchi. Muscle controls the amount of air which goes into the alveoli.
Macrophages- Found in the alveoli and defend body by bacteria.
Blood Vessels- Warm incoming air.
Surfactant Cells- Cells of the alveoli that produce a phospholipid, release a rich secretion on the surface of the alveoli, minimizes friction.
Hairs- Trap and filter dust particles.
Ciliated Epithelial Cells- Have goblet cells which produce mucus to trap dust particles.
- Intercostal muscles relax.
- Ribs and Sternum move down and in.
- Diaphragm muscles relax.
- Diaphragm more up (domed shape).
- Thorax volume decreases.
- Gas pressure in the thorax increases.
- Intercostal muscles contract.
- Ribs and sturnum move up and out.
- Diaphragm muscles contract.
- Diaphragm move down (flattens)
- Thorax volume increases
- Gas pressure in the thorax decreases.
Lung Diseases- Asthma
- Triggered by dust, smoke, pollution and cold air.
- Symptoms:- coughing, wheezing, shortness of breath.
- Smooth muscle contracts (spasms) which produces more mucus than normal, so airways become narrow, which in turn reduces ventilation and airflow is less efficient.
Lung Diseases- Emphysema
- Alveoli walls are damaged and replaced by connective tissue.
- Permanently stretches the elastin- does not force the air out of the alveoli.
- Surface area of alveoli is reduced.
- Symptoms:- chronic cough, shortness of breath, blue colouration to skin due to lack of oxygen.
- Caused by smoking and pollution.