CRRAB2 Flashcards
What is the branch after Segmental bronchi?
Terminal brnochiole
At rest, how long is blood in the capillary?
0.75 seconds
how much is in functional residual capacity?
2.5 L
What is total capacity of lungs?
7 L
How do you calculate functional residual capacity?
Helium! C1V1=C2(V1+V2) solve for V2
How do you calculate alveolar ventilation?
Alveolar ventilation = VCO2/PCO2 X K VCO2 is rate at which CO2 is produced. PCO2 is doubled, VA is 1/2
How do you calculate anatomical dead space?
Nitrogen is inhaled then look for steepest part of graph
How do you calculate physiologic dead space?
VD/VT=(PACO2-PExhaledCO2)/PACO2 Volume deadspace/tidal volum = Alveolar CO2 pressure - Exhaled CO2 all over Alveolar CO2
If there is unequal solubility in blood and blood-gas barrier, what kind of limitations does it have getting into blood?
Diffusion limited
How do you calculated diffusion capacity?
=Volume of CO transfered/partial pressure difference of CO.
Meanarterial pressure calculation?
Systolic pressure minus 2/3 difference
Normal atrial pressure is what?
5
Fick equation
Ecstasy stuff. XTC. you know it
rankings or pressure for zone 2 in breathing
Part>Palv>PVenous
How do hypoxic alveoli make capillaris close?
block voltage gated potassium channels and cause depolarization and calcium channels open
Causes of hypoxia
hypoventilation, diffusion limitations, shunt, ventilation:perfusion mismatch
How do you calculate the oxygen in air?
Air pressure-47 X 0.2093 (to take out humidity then the ratio that is oxygen
See if this is the same equation listed above for alveolar ventilation
/How do you calculate diffusion through a tissue in relation to area, thickness, molecular weight and solubility?
i. Area
ii. 1/thickness
iii. 1/(molecular weight)-1
iv. solubility
What is the calculation for alveolar PO2 with hypoventilation?
PAO2 = PIO2 – [PACO2/R]
P inspired dO2 - Alveolar CO2/R. R is Respiratory quotient which is produced CO2/O2. R is 1 with carbohydrate as substrate, R is 0.7 with fatty acid. normal is 0.8
How do you calculate flow through a shunt?
Does the base of the lung have a high or low ventilation to ratio?
The base has a low ventilation to perfusion ratio, so PO2 will be a little less than 100 and PCO2 will be a little more than 40. 89 and 42. Note, it has higher ventilation than the apex, but there is just that much perfusion.
Note, apex is opposite.
If a patient ahs a PO2 and PCO2 of 60 mmHg at normal atmospheric pressure normal?
No, PA-Pa calculation
PAO2 is calculated as PO2 inspired-(PCO2 arterial/R)
PAO2=149-60/0.8=74, and what was measured was 50, so the difference is 24 and it should never be mroe than 10 for young healthy individual, so ventilation to perfusion mismatch
Do a normal alveolar gas equation calculation.
PAO2=PIO2-PAlveolarCO2/R
100=150-40/0.8
Hemoglobin binding of oxygen in ml/g.
Normal hemoglobin in blood.
Hemoglobin binding at normal 760 mmHg pressure?
1.39 ml/g hemoglobin
normal hemoglobin is 15g/100ml
Max binding is 20 mlO2/100ml blood
What is oxygen concentration in blood required to live?
5 mlO2/100 mL blood. Hyperbaric oxygen will get it to dissolve at that much if carbon monoxide poisoning
What will cause oxygen shifts to the right in hemoglobin?
Decreased pH,
Increased CO2
Increased temp
Increased 2, 3 diphosphoglycerate (end product of RBC metabolism when hypoxic state to kick out O2 to tissues)
How much hemoglobin is dissolved in blood at normal alveolar O2?
0.3 mlO2/100ml blood
if it were 200 mmHg, oxygen is 0.6 mlO2/100 ml blood. It is linear.
Remember, hemoglobin gets maxed out with the curve
How does high carbon dioxide concentration effect RBC carrying capacity of O2?
decreases because it buffers with carbonic anhydrase and holds on to hydrogen like shown in the picture
What is the pH equation?
pH = pK + log (HCO3/CO2)
Higher pH with more HCO3 (more bicarb)
What is the herring breuer reflex?
Stretch receptor in lung suppresses further inspiration, slows breathing and heart rate. It calms you.
What is the stimulus for increased breathing in exercise?
Joint and muscle receptor from movement of limbs increasing resp rate
What is the compliance of the lung? What is something that increases it and worsens it?
200 mL/cm H2O. Change in volume/ change in pressure.
Emphysema increases compliance (obstructive lung disease destroys elasticity).
Fibrotic lung disease is restrictive and reduces compliance
What the shit is dipalmitoyl phosphatidylcholine
It is the fancy name for surfactant
How do you treat a premature baby respiratory wise? Why do you do it?
Surfactant is not sufficient until about 28 weeks (production starts in week 20). if too early, hyaline membrane disease and Respiratory Distress Syndrome(causes 20% of newborn baby deaths)
Give mom glucocorticoids before the birth to make baby produce it sooner, give the baby surfactant.
What causes airway closure? When do you see it?
Increased pressure from exhallation can push airway closed. Only happens at low volumes if young and healthy
Can be at functional residual capacity in old people with respiratory disease and cause air trapping
Pressure in intrapleural space?
-5 at rest, -8 during inspiration
What 2 things decrease airway resistance?
Sympathetics: epinephrine hits those beta two receptors and cAMP and airway dilation.
Larger lung volumes as negative pressure pulls airway open with inspiration
INCREASED RESISTANCE with parasympathetics hiting muscarinic receptors and more IP3 and Ca and airway constriction
What happens to Forced Expiratory Volume (FEV1) in first second of exhalation after a maximum inhalation in emphysema? In pulmonary fibrosis?
What happens to the Forced Expiratory Volume in first second to Fored Vital Capacity in emphysema? In pulmonary fibrosis?
Emphysema: Low FEV1 and low FEV1/FVC b/c low elasticity can’t get air out quickly, but can still put air into lung.
Restrictive lung disease (pulmonary fibrosis): low FEV1 but normal FEV1/FVC b/c can’t fill lung easily.
Breathing style if restrictive lung disease and obstructive lung disease? Work is force times distance.
Restrictive: short rapid breath, obstructive is slow deep breath
Most important receptor for breathing?
Central chemoreceptors which respond toH+ which is indirectly tied to PCO2 b/c CO2 has to cross BBB then carbonic anhydrase makes it into bicarb and H+ and that H+ stimulates to breath more.
THIS CAN BE COMPENSATED over time with COPD, so that is why you see slow breathing despite high PCO2 and low O2 in the resp disease patients. Their driving force is mostly low O2 (peripheral receptors), which is not as strong.
Why do you breath more with exercise?
Joint and muscle receptors sense moving to make you breath and a higher CO2 load to the lungs maybe. B/c you actually see a fall in PCO2 and a rise in PO2!!! pH is stable until you see lactic acid build up
What happens to PCO2 and PO2 in exercise?
fall in PCO2 and rise in PO2, probably b/c joint and muscle receptors moving and increased CO2 to the lung.
What creates baseline control of respiration?
Brainstem pacemakers that are in medulla and pons. Have unstable resting potential to make pacemaker actvity similar to the heart. CORTEX can override and allow panic attacks or breath holding.
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