Flashcards in 8. Gas Exchange and Carriage of Carbon Dioxide in the Blood Deck (56):
% of Nitrogen in atmosphere
% of oxygen in atmosphere
% of CO2 in atmosphere
definition of partial pressure
total pressure exerted by each gas
how to calculate partial pressure
% of total pressure in the air x total atmospheric pressure
where does oxygen diffuse into the blood?
name of law which explains equilibrium needed for gasses into liquid
which 2 factors affect the equilibrium reached for gasses to change into liquid
1. partial pressure of gas
2. solubility coefficient
definition for gas conc.
partial pressure x solubility coefficient
which is more soluble in water (O2 or CO2) and why?
CO2 as it has a higher solubility coefficient
another name for the rapture of the deep
what solubility coefficient does nitrogen have?
describe the pressure underwater
increases as you go more deeper
what occurs to the pressure of nitrogen when the total pressure increases?
effect of increased pressure of nitrogen on the body
increased diffusion of nitrogen into the blood
when does decompression sickness occur?
when the diver comes to the surface of the water - rapid changes from high to low pressure
what occurs in terms of nitrogen in decompression sickness?
nitrogen gas comes out of the blood
what are formed in decompression sickness?
bubbles in the tissues
symptoms of decompression sickness
fatigue, joint pain, dizziness, shortness of breath, unconsiousness, paralysis
what are the severity of the symptoms of DS dependent on?
the number of bubbles formed
treatment for decompression sickness
hyberbaric oxgentaion/ decompression chamber
how does a decompression chamber treat decompression sickness?
reduces the size of bubbles formed
what occurs during hyperbaric oxygenation?
oxygen partial pressure is increased to 3-4 atmospheres in a chamber- allowing increased diffusion of oxygen into blood
what is a gas embolism?
blockage of a blood vessel by a bubble of gas
what conditions does hyperbaric oxygenation treat?
- Bacterial diseases
- Carbon monoxide poisoning
- Gas embolisms
- Bone infections
- Smoke inhalation
- Near drowning
- Circulatory problems
what 2 specific bacterial diseases does hyperbaric oxygenation treat? and why?
as these are anaerobic
6 components of the respiratory membrane
1. fluid lining alveoli
2. squamous epithelial cells
3. epithelial basement membrane
4. interstitial space
5. basement membrane endothelium
4 factors affecting diffusion of gases across respiratory membrane
1. thickness of membrane
2. partial pressure difference
3. surface area
4. diffusion coefficient
thin membrane. Increase or decreased diffusion?
low diffusion coefficient.Increase or decreased diffusion?
large Surface area. Increase or decreased diffusion?
bigger difference between partial pressures across the membrane. Increase or decreased diffusion?
when can the thickness of the resp membrane increase?
diffusion coefficient of oxygen?
diffusion coefficient of CO2?
which has a higher PO2? alveoli or alveolar capillary?
which has a higher PCO2? alveoli or alveolar capillary?
what can change the pressure of oxygen in alveoli?
what is ventilation?
oxygenated air reaching a certain part of an organ
what is perfusion?
deoxygenated blood reaching a certain part of an organ
what is V/Q?
the ventilation-perfusion ratio
2 factors affecting V/Q
1. ventilation exceeds perfusion
2. perfusion exceeds ventilation
what circumstance occurs as a result of heart failure?
ventilation exceeds perfusion
what is shunted blood?
blood which is partially oxygenated - not fully saturated
what two bloods mix together during a physiological shunt?
deoxygenated blood (general) with deoxygenated blood from the bronchial arteries
how much blood pumped from the heart is a result of physiological shunt?
at rest, why is the PO2 in the alveoli low?
the lungs are not fully inflated
what occurs when the PO2 in the alveoli is low?
decreased diffusion due to smaller difference in partial pressures between membranes. this causes the blood to not be fully saturated with oxygen.
what does blood flow in different regions of the lungs depend on?>
where is the VQ ratio higher?
apex of lung
when standing, where does most ventilation occur?
apex of lungs
when standing, where does most perfusion occur? and why?
the base of the lungs - due to gravity the blood flows downwards
what occurs at the base of the lung in terms of PO2?
what occurs at the base of the lung in terms of PCO2?