Glossary of Physiology II Exam 2

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What type of cells secrete surfactant
Type II Alveolar cells
What two things make up the pleural cavity?
Space between the parietal pleura and the visceral pleura
What is the pressure normally like in the pleural cavity and what is it during inspiration?
Normally negative
Inspiration more negative
Where does gas exchange in the lungs occur?
In the respiratory division, final 7 branchings of the bronchis.
In the space in the lungs where no gas exchange occurs, what is this called?
Dead space, for every pound you have 1 mL of dead space.
How long does it take to get the air out of the lungs normally? Obstructive lung disease?
Normally 4-5 sec
Obstructive greater than 5 secs
What is the normal FEV1/FVC?
What is the FEV1/FVC in obstructive?
Normal 80%
Obstructive less than 60%
How does obstructive lung disease affect the FEF25-75%?
It is reduced due to the smaller airways leading to an increased time to expel vital capacity.
How does TLC, FRC, and RV change in obstructive lung (hard to get air out) disease?
TLC increases
FRC increases
RV increases
How does TLC, FRC, and RV change in restrictive (hard to get air in) lung disease?
TLC decreases
FRC decreases
RV decreases
Hypoxic Hypoxia
blood contains abnormallly low PO2 and Hb is poorly saturated. Occurs at high altitudes
Anemic hypoxia
PO2 is normal by HB concentration is low. Both oxygen capacity and oxygen content is reduced. CO poisening
Hypoperfustion hypoxia
caused by a reduction in blood flow to the tissues.
Histotoxic hypoxia
toxic substance (cyanide) interferes with the tissues ability to use O2
Dissolved CO2
amount of CO2 physically dissolved in blood. Only 5% of bloods total CO2 is in this dissolved form.
Carbamino compound
carbon dioxide binds with the globin portion of Hb to form carbamino hemoglobin. Faciliatates the unloading of CO2 (5% is carried this way)
90% carried this way.
Is V/Q ventilation ratios higher at the apex of the base
at the apex, however perfusion and ventilation are greater at the base.
Ventilation and Perfusion must equal what for gas exchange to occur?
ventilation and perfusion must be equal.
How are arterial P02 and alveolar PO2 related?
Arterial PO2 is always less then alveoloar PO2
What is the most important reason people are hypoxic?
due to V/Q ventilation inequalities.
What does the pre Botzinger complex do?
Causes expiration or inspiration
If arterial PCO2 increases, which decreases the pH in the brain ECF what kind of receptors are activated and what happens?
Central Chemoreceptors, ventilation is increased
Breathing air with low PO2

Alveolar PO2
Alveolar PCO2
Alveolar PO2 decreases
Alveolar PCO2 no change
Increased alveolar ventilation and unchanged metabolism

Alveolar PO2
Alveolar PCO2
Alveolar PO2 increases
Alveolar PCO2 decreases
Decreased ventilation and unchanged metabolism

Alveolar PO2
Alveolar PCO2
Alveolar PO2 decreases
Alveolar PCO2 increases
Increased metabolism and unchanged alveolar ventilation

Alveolar PO2
Alveolar PCO2
Alveolar PO2 decreased
Alveolar PCO2 increased
Proportional increases in metabolism and alveolar ventilation

Alveolar PO2
Alveolar PCO2
Alveolar PO2 no change
Alveolar PCO2 no change
What is the typical value for tidal volume?
500 mL
What is the typical value for TLC?
5800 mL
Three functions of surfactant?
1: promotes stability of alveoli (surface tension in large alveoli increases and surface tension in small alveoli decreases.
2: Increases complience of lungs and decreases work for each breath
3: minimizes fluid accumulation in the alveoli because of the reduced surface tension
What is the average PAO2?
100 mm Hg
What does CO2 remain constant at?
40 mm Hg
Describe the tissue differences between the base and the apex of the lung
Apex of the lung is relatively expanded versus the base that is compressed by the weight of the tissue above it. However this means the alveoli at the apex can expand much less than at the base.
Describe the pressure changes between the apex and the base
At the base intrapleural pressure is greater than the apex.
What is the V/Q ratios at the base and the apex
Apex 3.3 (over ventilated)
Base 0.63 (over perfused)
What is the composition of end capillary blood
O2 100 mmHg
CO2 40 mmHG

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