Lecture 9 Flashcards
2 regions of the respiratory system, whah happens in the first region ? (3 things)
upper (until larynx) and lower regions (trachea and rest)
in upper :
- warming air to 37 so that alveoli are not damaged by cold
- adding water vapor -> exhange epithelium doesn’t dry out
- filtering out foreign material
what is each alveoli surrounded by ?
elastic fibers, network or capillaries and lymphathic vessels
how is the thrachea held open ? how many times can the primary bronchi divide ?
Help open by cartilage rings.
Up to 22 times.
at what level of the division does the gas exchange start ?
bronchioles - alveoli
cite the layers where alveoli and capillari are in contact for gas exchange
vessel endothelium - fused basement membrane - surfactant - alveolar space
what is the mucus made of ? how can it move ?
saline + mucins
mucins are glycoproteins (protein core and carbohydrate side chains)
moves thanks to water and ciliated cells
how is saline generated ? one disease ?
Cl- brought from ECF to epithelial cell, then Cl- and Na+ go into the lumen -> concentration gradient and water follows to go to lumen (osmosis)
cystic fibrosis : malfunction of CFTR channel, the one that brings Cl- to lumen -> solid mucus
what acts as the “pump” in the respiratory system ?
diaphragm and thoracic cage (because most lung tissue is thin epithelium)
approximately how much pleural fluid ?
25-30 mL
how do we assess pulmonary function ?
how much air the person moves during quiet breathing and then with max effort
using a spirometer (inverted bell suspended in water)
what is the dead space ?
air that does not reach the alveoli and remains in conducting airways (no gas exchange)
about 150 mL
what is the difference between hyperpnea and hyperventilation ?
both are an increased respiratory rate / volume but :
- hyperpnea : increased metabolism (exercise)
- hyperventilation : no increased metabolism
list the 5 lung volumes that we look at in tests
1) dead space : volume of airways without gas exchange
2) residual volume : volume after max exhalation
3) exspiratory reserve volume : forcefully exhaled after end of normal respiration
4) tidal volume : normal respiration
5) inspiratory reserve volume : additional volume we can maximally inspire above tidal volume
how do we find the partial pressure of a gas in dry air ? and in humid air ? what changes at high altitude ?
Pgas = Patm * gas%
in humid : we substract water vapor pressure
Pgas = (Patm - PH2O) * gas%
At high altitude, the O2% doesn NOT change, but PO2 changes because Patm changes
partial pressure of oxygen in : dry air, alveoli, capillaries, venos blood
all in mm Hg
160
100
40
40
PO2 and PCO2 when alveolar ventilation increases and decreases
hyperventilation : PO2 increases, PCO2 decreases (what divers do)
hypoventilation : PO2 decreases, PCO2 increases
how does the perfusion / ventilation match work ?
if underventilated alveoli, the blood passing there does not get oxygenated -> arterioles constrict to divert blood to better ventilated alveoli
what are hypoxia and hypercapnia ?
hypoxia = too little oxygen on blood
hypercapnia = too much CO2 in blood
how is the carbon dioxide transported in blood ? (three aspects)
1) 7% remains dissolved in plasma
2) 23% binds to hemoglobin in red blood cell
3) 70% in converted to bicarbonate (via carbonic acid) in red blood cell, bicarbonate enters the plasma in exchange of Cl-. At the lungs, it’s pulled back into RBC and converted to CO2.
