respiratory system
structure and fuction
nasal cavity(鼻腔）
trachea
inner walls of the trachea and bronchi
lungs
alveoli
ribs
diaphram
the hair and the mucous layer on the wall can trap dust and forign particles
supported by a C-shaped ring of cartilage（软骨）
always open
secret mucus that trap particles and bacteria
have cilia that sweep and trapped particles and bacteria
bronchial divided to bronchioles
bronchioles end with alveoli
the site of gaseous exchange
numerous alveoli increase gas exchange surface area
alveoli are well-supplied with capillaries to enable the efficient of gas exchange
alveolar surface contain with a thin film of water
the wall only contain one cell thick
support the chest wall
dome-shaped and elastic tissue that contracts and relaxes
gas exchange
happens in alveoli
gases can dissolve and diffuse between the lungs and the circulatory system
from pulmonary artery--oxygen diffuses into red blood cells--carbon dioxide diffuses into alveolus--to pulmonary vein
the concentration of co2 in blood is higher than in alveoli
the concentration of o2 in alveoli is higher than in blood
oxygen binds to haemoglobin in red blood cell to form oxyhaemoglobin
different in inspired and expired air
oxygen
carbon dioxide
water vapour
temperature
inspied:more. expired:less
inspired:less. expired:more
inspired:varible. expired:always high
temperature:variable. expired:about body temperature 37
effect on exercise
exercise increase the frequency and depth of breathing
because muscle working harder and aerobically respiring more and they need high demand for oxygen
smoking
nicotine
carbon monoxide
tar
highly addictive（上瘾的)/increase the risk of heart disease
decrease the ability of red blood cells to transport oxygen
colorless--odorless
reduce the efficiency of gaseous exchange