Respiratory Adaptations Flashcards
Low oxygen available to tissues
Hypoxia
Total absence of oxygen being delivered to tissues
Anoxia
Low oxygen in the blood
Hypoxemia
Hypoxic Hypoxia
PaO2 is BELOW normal
What can cause Hypoxic Hypoxia?
Decreased PAO2 or the blood is unable to equilibriate fully with the alveolar air
Anemic Hypoxia
Oxygen carrying capacity of the blood is reduced
What can cause Anemic Hypoxia?
Carbon Monoxide
- It binds better to Hb, and oxygen will not be able to bind to be carried to the tissues
Circulatory Hypoxia
Heart cannot pump blood to tissue so the tissue is not receiving sufficient oxygen
What can cause Circulatory Hypoxia?
Sickle Cell Anemia
- The cell shape impedes circulation
Histotoxic Hypoxia
Cells in the tissues are poisoned and unable to use the oxygen that is correctly delivered to them
What can cause Histotoxic Hypoxia?
Cyanide
Normally, describe how the central chemoreceptors increase respiration rate
- CO2 diffuses into CSF
- CSF converts to H+ and Bicarbonate
- H+ activates central chemoreceptors to increase firing rate to pre-botzinger complex
= Increased ventilation rate
Hypocapnia
Reduced Carbon Dioxide in the blood
When low oxygen stimulates the peripheral chemoreceptors to increase ventilation, what decreases?
PaCO2!! – BAD for central chemoreceptors!
With hyperventilation caused by low oxygen, oxygen is increased and carbon dioxide is further DECREASED. Why is this bad?
H+ and thus, CO2 is needed in the CSF to activate the central chemoreceptors to drive our need to breathe!
What will compensate for decreased CO2 to maintain the drive to breathe?
Cells in the choroid plexus!
What do cells in the choroid plexus do in the case of hypocapnia?
Selectively pump out more H+ into the CSF so the CSF is back to normal pH even in the presence of low CO2
What enzyme do the cells of the choroid plexus contain?
Carbonic Anhydrase
Hypercapnia
Increased Carbon Dioxide in the blood
What does Hypercapnia do to the central chemoreceptors?
Increases H+ available in the CSF and central chemoreceptors now firing A LOT
With Hypercapnia, if the H+ becomes too high in the CSF, what happens to the central chemoreceptors?
The neurons do not function as well!
What do cells in the choroid plexus do in the case of hypercapnia?
Selectively pump out more HCO3- (bicarbonate) to the CSF to lower the acidity of the CSF
Increasing altitude ____ atmospheric pressure
DECREASES
With increasing altitude, what happens to the percentage of oxygen in the air?
Remains the SAME
With increasing altitude, the barometric pressure decreases. What will this do to the PAO2?
DECREASES - less oxygen available in body
What are the 3 steps in the acute response cascade to increasing altitude (lower atmospheric pressure)?
- Peripheral chemoreceptors increase ventilation in response to low oxygen levels
- Increased ventilation leads to decreased PaCO2
- Decreased PaCO2 causes decreased firing rates of the central chemoreceptors and ventilation decreases
What are the 3 steps in the acclimation response cascade to increased altitude (lower atmospheric pressure)?
- Cells of choroid plexus pump out more H+ into CSF so central chemoreceptors to fire normally even with low PaCO2
- Low oxygen causes release of Erythropoietin
- Cells of body increase number and size of mitochondria
With acclimation to higher altitude, why is erythropoietin produced?
Increases the number of RBCs = INCREASES ability to carry oxygen to tissues!
With acclimation to higher altitude, why do cells of the body increase number and size of mitochondria?
To be more efficient with the oxygen that they do receive
Decreasing altitude ____ atmospheric presure
INCREASES
Increases in barometric pressure will cause what level of gases in the body?
TOO HIGH
For every 10 m below sea level (water surface), the atmospheric pressure increases by how many atm?
1
Equation for calculating diver’s increased barometric pressure?
1 atm for every 40 m below and then + 1 ATM FOR THE AIR!!!
If a diver was 40m below sea level, what is their barometric pressure?
4 + 1 = 5 atm
With increased barometric pressure oxygen will accumulate in the body. What will form?
Superoxide anion (O2-) and Peroxide
Superoxide anion and peroxide effects on cells?
Highly reactive and toxic to cells
Symptoms of too much oxygen in the body?
Coughing, sore throat, tinnitus, convulsions, death
With increased barometric pressure nitrogen will also accumulate in the body. What does it act like on our CNS neurons?
Alcohol
Nitrogen dissolves in our plasma. True or false?
True
When a diver ascends, they must go slow. Why?
So the nitrogen can convert back to gas and be expelled by the lungs
What happens if a diver ascends too quickly?
The nitrogen will not have enough time to convert back to gas and be expelled in the lungs
= Gas bubbles accumulate in tissues and block circulation
When nitrogen gas bubbles accumulate in tissues, what is this called?
Bends or Decompression sickness
Symptoms of too much nitrogen bubbles in the body?
Pain, itching, paralysis
During a diver’s ascent, what body part must remain open so air can leave?
Glottis
If the glottis remains closed during a diver’s ascent, what may occur?
Air embolism
