9/17 Repiratory physiology introduction Flashcards by Christopher Andersen

what are some functions of respiratory system?

Gas Exchange; (matabolism, acid/base balance); 2. olfaction; 3. processing inhaled air (BTPS); 4. Blood reservior; 5. filter small emboli; 6. biochemical reactions (angiotensin II from I; remove some hormones)

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what does BTPS stand for in lung function

body temperature, ambient pressure, water saturated.

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how much of the blood is in the pulmonary vessels?

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what is Pressure?

directly related to force per area over which the force is applied (F/A)

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what are the common units of pressure?

Pascal (newton/m2); PSI (pounds/in2); mmHg (manometer)

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ideal gas law

PV-nRT

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what is a partial pressure?

the partial of a gas is the pressure that it would have if it occupied the volume of the mixture. similar to conc.

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how does Partial presssure affect gass dynamics

drives the diffusion and reaction of the gasses

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how is conc. of gas in solution related to the partial pressure?

Ca=Pa* solubility (directly related)

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the normal range of resperatory volume in normal breathing

Tidal Volume

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Total air volume forcibly expired after full inspiration.

forced vital capacity (usually measured over 3-5 sec)

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the volume of air expelled from max inhale in 1 sec

Forced Voume Expired (FEV1)

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the ratio of air expelled in the first second to the toal expelled over about five seconds

FEV1/FVC

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what is a normal FEV1/FVC

0.7-0.8

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what is a FEV1/FVC that is abnormal and indicative of asthma?

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what problems whould cause a lower FEV1/FVC?

asthma and problems that cause obstructive diseases (copd etc.)

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what problems would cause a greater than normal FEV1/FVC?

restrictive diseases where the lung has problems getting enough air in (Fibrosis)

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what is the RV for lungs?

the reserve volume, or the air that is left in the lung after all of the air is exhaled as possilbe.

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what would the purpose of the RV be for the lungs

to prevent lungs from collapsing

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what is it called when you measure the volumes of air going in or out of the lungs?

Spirometry

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what is the partial pressure of O / CO2 in inspired air

O is 160 mmHG; CO2 is 0

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what is the partials of O/CO2 in the trachea

O2: 150/ CO2: 0

why does the Pa of O2 go down in trachea?

because of humidification

what is are the partial pressures of O/CO2 in alveolar

O: 100; CO2: 40

what is the partial in the blood

O: 40; CO2: 46 before exchange and O: 100; CO2: 40 after

what is perfusion-limited mean for the lungs?

the Pa=PA before end of capillary, to get more gas into the blood perfusion rate must increase. (must get more blood in there to get more gas exchange or limited by blood flow)

what is diffusion-limited mean for the lungs

limited by the resistence to diffusion accross the cappilaries, with fibrosis this is thick alveolar walls. also seen with strenuous exercise.

what is the ventilation and perfusion

this is the ratio of rate of ventilation vs. the rate of blood flow.

what is normal ventilation and perfusion?

V/Q of .8

what are the partial pressures that equate to a normal ventilation and perfusion?

O2 is 100mmHg and CO2 is 40mmHg will give a V/Q during .8

why would V/Q vary from the top to the bottom of the lung?

standing up will lead to gravity affecting the blood flow. the top of the lung there is less blood flow and the V/Q is higher (around 3.0) (there is more air than there is blood). and at bottom v/q is 0.6 (lowest)

how does the Q; V; V/Q; PaO2; PaCO2 vary from the top to the bottom of the lung?

Lowest/Lower/highest (3.0)/highest (130mm HG)/lower (28 mmHg). The bottom of the lung is just opposite

what leads to V/Q mismatch or defects?

Dead space, shunt, and problems inbetween

what is a dead space that leads to V/Q defects in the lungs?

there is no capilary to exchange gas with the aveoli. the V/Q is infinite

what is a shunt in the terms of V/Q

when there is no avioli to gas exhnage with the capilary the V/Q=0

what could lead to high V/Q?

more avioli than capilary flow next to it

what could lead to low V/Q?

very high capilary pressence comparied to the avioleio pressence.

what will happen to make up for an embolism in a pulmonary artery?

blood is auto divertded to other alvioli, which will be hyperperfused. THE BRONCHILES SUPPLYING THE ALVEOLI CONTRICT

what would cause the bronchiles to constrict if the V/Q goes to infinite?

alkalosis, that is the pH goes up due to the lack of CO2 becoming an acid to keep pH down

what happens during a shunt situation (V/Q is zero) in the lungs

hypoxic pulmonary vasocontriction (closes the capilary off and sends blood elsewhere)

why does the resistance to blood flow in the lungs go up at high altitude (makes BP go up)

the capilaries start to restrict due to hypoxic pulmonary vasocontriction.

what happens to the V/Q if the dif. in partial pressure in arteries and capilaries gets too large?

get a large V/Q mismatch which leads to hypoxia and repiratory acidosis

what is hypoxia

Lack of oxygen in the tissue due to a lack of oxygen in the blood.

what is respiratory acidosis

Excessively acidic condition due to excess CO2 in the presence of water

how would an extreme local mismatch of PA and Pa (V/Q mismatch) affect the system as a whole

can produce hypoxia and repratory acidosis (even if the average for the whole is normal

how does the brain control breathing?

from the inspiratory center in the medula. takes infor from peripheral chemoreceptors, central chemoreceptors, lung stretch receptors, muscle and joint receptors, pheumotaxic center, apneustic center and then gives feedback to the daphragm to control breathing.

what happens to the arterial blood during exercise

No change in PaO2; no change in CO2 no change or slight lower pH.

what happens to venous blood during exercies

the PV CO2 goes up.

what happens to pulmonary blood doue to exercise

up cardiac output; up pulmonary blood flow; V/Q more even in the lungs. down physiologic dead space.

waht happens to O2-Hemoglobin curve due to exercise

Shifts to the right; P50 up; affinity for O2 goes down. (takes greater pressure of oxygen to bind to saturate hemoglobin)

what happens to ventilation in altitude

Up Va

what happens to arterial blood at altitude

down PaO2; up pH (respiratory alkalosis)

what happesn to pulmonary blood flow at altitude

Up resistance to pulmonary flow; up pulmonary artery pressure; hypertrophy of right ventricle.

what happens to O2-hemoglobin curve at altitude.

up 2,3-DPG; shift to right. up P50; down affinity for O2.