Structure of the Lungs
Trachea - flexible airway supported by rings of cartilage, preventing collapse. Cilia in the trachea move the mucus to the throat.
Bronchi - two divisons of the trachea, each leading to one lung.
Bronchioles - branching subdivisions of the bronchi.
Alveoli - minute air-sacs with a large surface area and thin wall (increasing the efficiency of gas exchange).
- The external intercostal muscles contract and the internal intercostal muscles relax.
- The ribs are pulled upwards and outwards, increasing the volume of the thorax.
- The diaphragm contracts, flattening it, increasing the volume of the thorax.
- The increased volume of the thorax decreases the pressure in the lungs.
- Atmospheric pressure is more so air is forced into the lungs.
- The internal intercostal muscles contract and the external intercostal muscles relax.
- The ribs are pulled downwards and inwards, decreasing the volume of the thorax.
- The diaphragm relaxes, returning to it's original shape, decreasing the volume of the thorax.
- The decreased volume of the thorax increases the pressure in the lungs.
- Atmospheric pressure is less so air is forced out.
Pulmonary ventilation - the total volume of air taken into the body in one minute.
Tidal volume - volume of air normally taken in at each breath, at rest.
Ventilation rate - number of breaths taken in one minute.
Pulmonary ventilation = tidal volume x ventilation rate
Persisant cough, tiredness, loss of appetite, fever, coughing up blood.
Spread through the air in droplets.
- The bacteria grow and divide in the upper regions of the lungs where there is a plentiful supply of oxygen.
- White blood cells accumulate at the site of infection to ingest the bacteria.
- This leads to enlargement and inflammation of the lymph nodes (primary infection).
- Many years later these bacteria can re-emerge and they destory the tissue of the lungs which the sufferer coughs up (post-primary tuberculosis).
Shortness of breath, dry cough, weakness and fatigue.
- Scars form on the epithelium lining, causing them to become irreversibly thickened. This reduces the efficiency of gas exchange.
- It reduces the elasticity of the lungs making it difficult breathe out.
Difficulty in breathing, wheezing sound, coughing.
Caused by air pollutants, pollen etc.
- White blood cells on the linings of the bronchi and bronchioles release histamine.
- The linings of the airways becomes inflammed.
- The cells on the epithelium lining secrete more mucus.
- Fluid leaves the capillaries and enters the airways.
- Muscles surrounding the bronchioles contract, constricting the airways.
Shortness of breath, cough,bluish skin coloration.
- The elastin of the lungs becomes permanently streched.
- Lungs aren't able to force all air of the alveoli.
- Surface area of alveoli is reduced and they can burst.