BIOL 221 Lecture Notes - Lecture 7: Partial Pressure, Perfusion

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peachbeetle258

3 Mar 2020

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Pressure exerted by a gas in a mixture is directly proportional to the. E. g. , o2 = 20. 9% of air at sea level where total gas pressure = 760 mm hg, Po2 = 20. 9% x 760 mm hg = 159 mm hg. Dalton"s law states that the pressure exerted by a gas in a mixture of gases is directly proportional to the percentage of that gas in the mixture. The higher the percentage, the greater the partial pressure. Partial pressures are calculated by multiplying the percentage of gas by the total pressure. At sea level barometric pressure (total gas pressure) is approximately 760 mm hg (although this changes slightly with the weather). The partial pressure of oxygen at sea level is around 159 mm hg. Partial pressures of other gases are calculated in the same way. Note that the partial pressures of carbon dioxide and water are normally very low.

Related Questions

fill the blanks with the terms given

Terms: 0.21, 21, 78, 760, altitude, blood, Boyle's, Dalton's,decimal, decreased, diaphragm, directly, external intercostal,Henry's, into, inverse, lowers, out of, oxygen, parasternal,partial, percent concentration, pressure, solubility, temperature,total, volume

_________ law states that there is a/an ________ relationshipbetween [listed alphabetically] the _________ of a gas and the___________ of the gas. That is, an increase in one of the factorsis associated with a decrease in the other factor and vice versa.Thoracic cavity size determines the volume of the air in the lungs.Thus, this law is fundamental to explaining why an increase in thethoracic cavity size due to expansion of the rib cage in thehorizontal [front-to-back and side-to-side] directions viacontraction of the ___________ and _________ muscles, (listedalphabetically) and vertical [up-and-down] direction viacontraction of the ___________ causes a resultant decrease inintrapulmonary pressure, creating a pressure gradient that drivesair _____________ the lungs. Conversely, it explains why when thesize of the thoracic cavity is _________ by relaxing the musclesused during inspiration, the pressure of the gas in the lungsincreases, exceeding atmospheric pressure, creating a pressuregradient that then forces air _________ the lungs ________ lawstates that the _______ pressure of a mixed gas is equal to the sumof the ___________ pressures exerted by each of the individualgasses in the mix, which are exerted independent of one another.This law is important to pulmonary physiology because theatmospheric air we breath is a mixed gas that contains roughly__________% nitrogen and _______% oxygen. Moreover, according toHenry's law, it is the partial pressure of the oxygen in the air webreath that is the main determinant of how much of the air's oxygenwe can drive into our blood and make available to the body. A gas'spartial pressure can be calculated by multiplying the totalpressure of the mixed gas by the gas's ____________ in the mixedgas. Thus, the partial pressure of oxygen, at sea level isdetermined by multiplying total atmospheric pressure at sea level -which equals ___________ millimeters of mercury (denoted mm Hg) by________ - oxygen's percent concentration in atmospheric air,expressed as a ____________. ________ law actually states that theamount of gas we can drive into solution is _________ dependentupon 3 factors. These 3 factors are 1) the solubility of theparticular liquid for the particular gas you are considering, 2)the temperature (more gas can be driven into liquids at lowertemperatures than at higher temperatures) and 3) the partialpressure of the gas under consideration. In the body, theparticular gas we are interested in driving into a fluid is__________ and the particular fluid we are interested in drivingthe gas into is our ___________. Because blood has a particularsolubility for oxygen - and this is constant, and because thehomeostatic mechanisms in the body keep body temperature relativelyconstant, this means the single most important factor thatdetermines how much oxygen can be driven in to our blood is thepartial pressure of the oxygen in the air we breath. At sea level -the partial pressure of oxygen in atmospheric air = 760 x 0.21 =159 mm Hg. However, if one climbs to the peak of Mt. Everest, wherethe air is still a mixed gas that contains only ~21% oxygen, butthe air there is 'thinner' i.e. there is just less of it up there,the total pressure of the gas drops to about 250 mm Hg, whichsignificantly __________ the the partial pressure of oxygen and theamount of air that can be forced into the blood at that altitude.Thus this gas law explains why many individuals initiallyexperience ____________ sickness when they vacation in the Rockiesor the Swiss Alps but normally live at much lower elevations.

greenbeetle772

PHYSIOLOGY

11. A subject is connected at FRC to a bag containing 2L of 8% He, 92% O₂. He rebreathes from the bag until mixing is complete; at which time the fraction of He is 4.6%. What is the value of FRC?

A. 1.15L

B. 1.48L (can you please explain this answer)

C. 2.48L

D. 3.48L

E. It cannot be calculated from the information given

The minimum time it takes a normal person to go from residual volume (RV) to total lung capacity (TLC) is less than the minimum amount of time to go from TLC to RV. The most probable explanation for this effect is:

A. the chest wall tends to spring outward when the respiratory system is at RV.

B. the chest wall is less compliant at RV.

C. inspiratory muscles are stronger than expiratory muscles.

D. the lungs have less recoil at TLC.

E. the airways tend to collapse during forced expiration. (can you please explain why this is the answer)

Two gases, A and B have the same partial pressure difference across the alveolar capillary barrier. Gas A has a molecular weight of 36 and solubility of 24 while gas B has a molecular weight of 16 and solubility of 2. What is the rate of diffusion of gas A through the barrier compared to gas B?

A. 12:1

B. 8:1 (can you explain why B is the answer?)

C. 6:4

D. 4:1

E. They are the same.

If an individual with a tidal volume of 500 ml and a dead space volume of 100 ml were to exercise and double the CO₂ production, with no change in respiratory rate, what tidal volume would be required to maintain their original P_CO2 of 40 mm Hg?

A. 1200 ml

B. 1100 ml

C. 1000 ml

D. 900 ml (can you explain why the answer is D?)

E. 800 ml

39. What is the total amount of oxygen in the arterial blood (in ml O₂ /100ml blood) of an individual who has P_O2=90mm Hg, P_CO2=40mm Hg, Hb=15g/100ml, hemoglobin saturation = 95%, (solubility coefficient of O₂=0.003 ml O₂/100 ml blood/mm Hg; at saturation Hb binds 1.34 ml O₂/g)

A. (0.95 x 15) + (95 x 0.003)

B. (90 x 1.34 x 15) + (95 x 0.003)

C. ((90 - 40) x 1.34 x 0.95) + (90 x 0.003)

D. (0.95x 1.34 x 15) + (90 x 0.003) (can you explain why the answer is D?)

E. none of the above

pearyak206

1. Match the word 1-39 above, with the descriptions labled a-t. Word 1-39 can be uses only one please!!

1. alveolar macrophages 2. alveoli 3. Bohr effect 4. bronchi 5. bronchiole 6. cerebral cortex 7. chloride shift 8. compliance 9. costal breathing 10. Daltonâs law 11. diaphragmatic breathing 12. epiglottis 13. eupnea 14. expiratory reserve volume 15. fauces 16. functional residual capacity 17. Haldane effect 18. Henryâs law 19. hilum 20. hypothalamus 21. inferior, middle, and superior nasal meatuses 22. inspiratory capacity 23. larynx 24. limbic system 25. medulla oblongata 26. nose 27. paranasal sinuses 28. pharynx 29. pleural membranes 30. pons 31. primary bronchus 32. secondary bronchus 33. surface tension 34. surfactant 35. terminal bronchiole 36. tertiary bronchus 37. total lung capacity 38. trachea 39. vital capacity

a) -------------------- serves as a sound resonating chamber; contains tonsils; directs air inferiorly

b) ------------------- passes air from pharynx into windpipe; site of sound production

c) ------------------ resonate(s) sound; not part of pharynx

D) ------------------ opening from oral cavity into pharynx

E) ----------------- carries air to a segment of a lung

F) -------------------- carries air directly into a respiratory bronchiole

G) ----------------- surround the lungs

H) ------------------ reduces surface tension at sites of gas exchange

i) -------------------- actual sites of gas exchange

j) --------------------- normal, quiet breathing

k) ----------------------- shallow breathing using just the external intercostal muscles

l) ------------------ amount of effort required to expand the lungs and chest wall

m) ------------------- tidal volume + inspiratory reserve volume, usually about 3600 mL in males

n) ----------------- tidal volume + inspiratory reserve volume + expiratory reserve volume; usually about 4800 mL in males

o) ------------------- residual volume + expiratory reserve volume; usually about 2400 mL in males

p) -------------------- states that the amount of gas that will dissolve in a liquid is proportional to the partial pressure of that gas and its solubility

q) ---------------- when pH decreases, O₂ saturation of hemoglobin decreases

r) ------------------ each gas in a mixture of gases exerts its own partial pressure

s) ------------------- sets basic rhythm of breathing

t) ------------------------ includes the pontine respiratory group

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BIOL 221 Lecture Notes - Lecture 7: Partial Pressure, Perfusion

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