BSC 1086C Lecture Notes - Lecture 9: Central Chemoreceptors, Respiratory Center, Hypercapnia

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lavenderpig501

22 Feb 2017

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Chapter 24- external & internal respiration and gas transport. Therefore, the partial pressure of each gas is directly proportional to its percentage in the mixture: fictional planet reuter a has a total atmospheric pressure of 900 mm hg. Oxygen makes up 30% of the atmosphere and co2 5%. At equilibrium, the partial pressures in the two phases will be equal: the amount of gas that will dissolve in a liquid also depends upon its solubility. Neither; both have a partial pressure of 150 mm hg: alveolar gas has a different composition tha atmospheric air. This gradient is still sufficient to cause a diffusion a diffusion of co2 from the blood to the alveolus: the respiratory membrane has to be extremely thin for gases to move across via diffusion only. Any thickening of the membrane of fluid connection in the alveoli will impair gas exchange: the same can be said about the overall surface area.

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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

True of False: Freshwater environments have a higher concentration of oxygen than saltwater environments.

QUESTION 2 If the difference in partial pressure of gas on either side of the barrier to diffusion is 0, which of these events will occur?

The area for gas exchange will increase to accommodate this similarity.

The constant for diffusion will decrease.

The rate of diffusion will be 0.

The distance thickness of the barrier to diffusion will also be 0.

QUESTION 3 On the x-axis of the oxygenâhemoglobin equilibrium curve is the partial pressure of oxygen in tissues. Which type of blood is most likely to be represented by the right-hand side of the axis? (Hint: the oxygen-hemoglobin equilibrium curve is figure 45.14 in your book on pg 913)

blood found in the left ventricle

blood found in the right atrium

blood found in the superior vena cava

blood found in the inferior vena cava

QUESTION 4 Which of these is an example of pulmonary circulation?

Blood is pumped from the right ventricle to the lungs.

Blood is pumped from the left ventricle to the aorta.

Blood is pumped from the aorta to the cardiac vein.

Blood is pumped from the inferior vena cava to the right atrium.

QUESTION 5 O2 will diffuse from blood to tissue faster in response to which of the following conditions?

an increase in the PO2 of the tissue

a decrease in the PO2 of the tissue

an increase in the thickness of the capillary wall

a decrease in the surface area of the capillary

QUESTION 6 Which of the following promotes oxygen release from hemoglobin?

a decrease in temperature

a decrease in carbon dioxide levels

a decrease in pH

a decrease in carbonic anhydrase

QUESTION 7 How does the medulla oblongata sense the amount of carbon dioxide in the blood?

A. Carbonic anhydrase produced by cells performing cellular respiration is exported and travels though the blood, and binds to a receptor on the medullary respiratory center, which causes a signal amplification resulting in a change in gene expression which results in the production of proteins that will cause the diaphragm to contract

B. CO2 produced by cells performing cellular respiration reacts with blood plasma for form an acid, which increases the pH of the blood, which causes the medullary respiratory center to contract the diaphragm

C. CO2 produced by cells performing cellular respiration reacts with blood plasma for form an acid, which decreases the pH of the blood, which causes the medullary respiratory center to contract the diaphragm

D. A and B

E. A and C

QUESTION 8 Which of the following parts of the lung are considered "dead space"? A. The alveoli B. The trachea C. The bronchi D. B and C E. All of the above

QUESTION 9 Which of the following blood vessels have the thinnest walls?

arteries

arterioles

capillaries

venules

veins

QUESTION 10 How does the interstitial fluid return to the bloodstream?

A. Interstitial fluid flows into the capillary where the osmotic pressure driving fluid into the bloodstream is greater than the blood pressure driving fluid out of the blood

B. Interstitial fluid flows into the capillary where the blood pressure driving fluid into the bloodstream is greater than the osmotic pressure driving fluid out of the blood

C. Interstitial fluid leaves the tissue via lymphatic ducts and travels through the lymphatic system, which returns the fluid to the veins. D. A and C

E. B and C

QUESTION 11 True or False: When an electrocardiogram (EKG or ECG) shows a flat line (aka asystole), medical personnel will restart the heart using a defibrillator.

azureprairie-dog128

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

BSC 1086C Lecture Notes - Lecture 9: Central Chemoreceptors, Respiratory Center, Hypercapnia

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