Nasal cavity; has cells that produce mucus; that together with hairs/cilia; trap and propel dust/microbes to the pharynx to be breathed out/swallowed;
Cavity is supplied with capillaries; that warm the air for faster flow in the channels;
Epiglottis; covers the trachea during swallowing; so that particles of food and water may not enter the trachea;
Trachea and bronchi; have cartilage rings; to keep the passages open/prevent them from collapsing; so that air moves in and out freely and continuously; are also lined with mucous membranes which have hairs/ciliated; whose movement/wafting push out dust particles collected in the passages into the pharynx; richly-supplied with blood vessels; to warm the air; for faster flow;
Lungs; have numerous alveoli; to increase the surface area for gaseous exchange;
Alveoli have a thin epithelium; to reduce the distance through which gases diffuse for easier and faster diffusion; alveoli are moist; to dissolve oxygen for faster transport;
Lungs are spongy; because of many air sacs that contain a large amount of/volume of air; Lungs are also supplied with many blood vessels; for transportation of gases; they are also supplied with a network system of trachea, bronchi and bronchioles; to provide an efficient system/large surface area for gaseous exchange; Lungs are enclosed in a pleural membrane; which secrete pleural fluid; that protect the lung surface; lubricate the chest cavity; allowing smooth movement of lungs as they change volumes;
Ribs have intercostal muscles; that moves/contracts and relaxes to allow for inhalation and exhalation; ribs also protect the lungs; has the diaphragm muscles whose contraction and relaxation leads to inhalation and exhalation respectively;
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