Respiratory system Flashcards
which part of the brain signals the diaphragm to contract resulting in inspiration?
medulla oblogata of the midbrain
what happens to the diaphragm when it contracts?
it flattens, expanding the chest cavity and creating negative pressure relative to the env. air comes into lungs
what happens when diaphragm relaxes?
it is dome shaped and it will cause the chest cavity to shrink. the air will be forced out (expiration)
what does the nasal cavity do?
filter, moisten, and warm incoming air
what does the cilia do?
move the mucous and dust back toward pharynx(throat) so it can be removed by spitting or swallowing.
what is the function of the pharynx(throat)?
passageway for food and air
what is the larynx?
voice box! sits behind epiglottis. larynx contains the vocal cords
what does the epiglottis do?
prevents food from entering trachea (windpipe) during swallowing
where is the trachea?
lies in front of esophagus. it splits into right and left bronchi- which branch into bronchioles… which terminate in grape like clusters called alveolar sacs composed of tiny alveoli.
what does 98% of oxygen bind to ?
protein called hemoglobin ( 4 subunits, each with heme cofactor- iron in the centre)
what is copperativity?
as one iron atom in hemoglobin binds to oxygen, oxygenation of other heme groups is accelerated. same happens with O2 release
what is the oxygen saturation of hemoglobin dependent on?
1) oxygen pressure (sigmoidal relationship)
2) carbon dioxide pressure
3) ph
4) temperature of blood
which factors cause lower hemoglobin affinity for oxygen?
inc in ph, inc in temp and inc CO2 ( dec affinity = shift to the right)
what can cause a shift to the left?
CO ( bc it has a really high affinity to hemoglobin - more then O2)
Carbon dioxide is carries in the blood in which three forms?
1) physical solution
2) as bicarbonate ion (most commonly)
3) in carbamino compounds ( combined with hemoglobin and other proteins)
