week 8: Respiration Flashcards
what does the pharynx do
directs food to the stomach and air to the lungs.
what directs food to the stomach and air to the lungs
pharynx
what is moved upward when swallowing to prevent food entering the trachea
larynx
where does the gas exchange occur in the lungs?
alveoli
what are the 6 things that air passes through when inhaled
pharynx, larynx, trachea, bronchi, bronchioles finally reaching the alveoli.
why is the gas exchange in the lungs so efficient
diffusion area is very large, walls of capillaries are thin so diffusion distance is short.
what is the structure of the alveoli
air sacs at the end of the bronchioles
how is gas exchanges at the alveoli?
oxygen diffuses through the moist film of the epithelium and into the capillaries
carbon dioxide diffuses from the capillaries across the epithelium and into the air space
what is the composition of the atmosphere
78% nitrogen
21% oxygen
0.04% carbon dioxide
~1% water
why is a large reserve of oxyhemoglobin important (97% saturation) when only 22% is released to tissues
to meet demands of exercise
incase the the supply of oxygen is interrupted
how is carbon dioxide transported
most CO2 combines with water in erythrocytes to produce carbonic acid which is transported out of the cell into the plasma.
what is the Bohr shift
increase in co2 pressure in very active tissue causes fall in PH
A fall in the PH decreases the affinity of hemoglobin for oxygen
what happens as a result of the Bohr shift
more oxygen is released and made available to the tissue
what part of the brain controls involuntary breathing
medulla oblongata
what is the name of the disease which has the symptoms;
alveoli become dry and brittle and eventually rupture
emphysema
