Respiratory 2 Flashcards
gas molecules exert pressure by collisions irregardless of the size. If the partial pressure of oxygen in the blood is lower than the air, what will happen. When will it stop
Diffuse into bloodstream
When equilibrium is reached
When is alveolr pressure equal to atmospheric pressure?
When no air is flowing in/out of lungs
What is the relationship between dissolving and partial pressure?
The higher the PP, the more it will dissolve
What is hypoxia?
Reduced pp O2
What is hypocapnia?
Reduced pp CO2
What is hypercapnia?
Increased PP CO2
Why is alveolar pp O2 lower than air?
Due to mixing with water when inhaled
WHat is perfusion?
Blood supply
What happens if the ventilation to perfusion ratio is mismatched/
full equilibrium cannot be reached
Describe oxygens solubility in plasma
Poor
Describe haemoglobin
Iron ion with 4 haem units and globin chain
What is the purpose of globin?
Prevent oxygen binding being irreversible
What is the oxygen capacity of blood
200 ml per litre
What is cooperative binding?
Binding of O2 to haem group increases affinity until saturation point
When does the oxygen haemoglobin curve shift right?
Increased temperature
CO2
Acidity
DCG
In anaemia animals, how does the percentage saturation of haemoglobin Chang?
It doesn’t
The foetal haemoglobin curve is where in comparison to the adult?
Left
How is carbon dioxide transported?
Mainly by HCO3
Some by proteins
Few dissolved in plasma
What is the equation for H20 and C02
H20 + CO2 —> H2CO3 —> H+ + HCO3-
What is chloride shift?
Chlorides move into cell when HCO3- leaves to maintain electrochemical gradient
Can protons diffuse out of RBCs? How do they bind?
No
Bind to deoxyhaemoglobin
Where do alveolar vessels run?
Alveolar septa
Where do extra alveolar vessels run?
Pulmonary arteries/veins
Which lung fields are most perfused?
Caudodorsal
What happens when lungs are over inflated?
Capillaries are crushed
Describe pulmonary vascular difference
Opposite to system resistance
Increased diameter decreases resistnce
Does alveolar hypoxia lead to vaso constriction or dilation?
Vasoconstriction
What is the equation for pulmonary vascular resistance?
P pulmonary artery - P left atria
Divided by cardiac output
How is rhythmic breathing generated and maintained
Pacemaker neurons in medulla oblongata
Central pattern generator provides RR and depth
What is the Hering-Beur reflex?
Baroreceptors in lung detect stretch and decrease action potentials to lungs to prevent over inflation
Where are central chemoreceptors? What do they monitor?
Brain
Pa CO2 only
How do chemoreceptors in the brain detect CO2?
CO2 crosses the BBB
Carbonic anhydride generates HCO3- and H+
Where are peripheral chemoreceptors found? What do they monitor?
Carotid and aortic bodies
Monitor Pa CO2, Pa O2 and arterial H+
Which nerves innervate the carotid and aortic bodies?
CN IX
CN X
