1. THE RESPIRATORY SYSTEM
provides oxygen to the cells and removes carbon dioxide from the body.
works closely with circulatory system.
made of following parts:
nasal cavity
mouth
trachea
bronchi
lungs
diaphragm
Nelson Science

2. Gas Exchange travels through the trachea (windpipe) to the lungs.
trachea has cells that have hairlike projections called cilia.
Cilia filter out and remove foreign materials (such as dust)
oxygen enters the bloodstream in the lungs by diffusion and carbon dioxide leaves
gas exchange takes place in the alveoli, which are surrounded by capillary networks containing blood.

3. Breathing
Air is drawn into the lungs by inhaling and is then pushed out by exhaling.
Breathing is controlled involuntarily.
muscles move ribs and lower diaphragm making air flow into lungs (inhalation)
opposite happens for exhalation

4. Diseases
constantly exposed to substances in the air, so it can be affected by many different diseases.
Tuberculosis (TB) - bacteria that are breathed into the lungs, where they grow
Tobacco smoke - contains carcinogens
This chest X-ray shows evidence of TB in the upper part of the lung on the right.