4.10 Cardiovascular System and Respiration in Extreme Conditions Flashcards
How is the atmospheric partial pressure calculated
PO2 + PCO2 + PN + P….
What is an the alveoli other than oxygen
carbon dioxide, nitrogen and water vapour (the water vapour pressure depends on our body temperature)
What is the primary stimulus for changing ventilation rates at sea level
Partial Pressure of Carbon Dioxide
What does the primary stimulus for changing ventilation rates change to at high altitude
Severe hypoxia becomes the main stimulus. Peripheral chemoreceptors detect this hypoxia and increase their firing rate when po2 falls below 60mmHg. This leads to increased ventilation (both rate and depth of breathing).
What is respiratory alkalosis
When increased ventilation rates lowers pCO2, causing a rise in blood pH (alkalosis). The body then has to compensate.
At altitude, the body will hyperventilate due to the lack of oxygen, causing respiratory alkalosis. However, over several days the body will acclimatise and compensate for the respiratory alkalosis.
What is produced as the body continues to adapt to altitude hypoxia.
As the body continues to adapt to oxygen and hypoxia, blood cells produce more 2,3-BPG molecules, they bind to haemoglobin and reduce its affinity for oxygen. This means oxygen is more easily released to tissues, which is beneficial in low-oxygen environments like high altitudes or chronic lung disease. This will cause a shift right in the dissociation curve
What are hypoxia inducible transcription factors
Hypoxia inducable transcription factors can be activated in the presence of hypoxia, leading to the activation of genes producing proteins helping with hypoxia such as erythropoetin (a hormone that your kidneys naturally make to stimulate the production of red blood cells)
Describe some altitude related illnesses
acute alitude sickness - symptoms similar to a hangover- at 5000m+ everyone will get it but some will get it at lower (not related to previous fitness) - due to not having a full respiratory aclimatisation process causing co2 to accumulate and not be cleared out
high altitude cerebal edema: - symptoms of mental confusion, lethargy , ataxia then causing coma and death within a few hours
high altitude pulmonary edema - cough, shortness of breath, chest tightness, blue lips etc, also fatal within a few hours
What are some long term respiratory adaptation in populations at high altitudes
-larger lung values, increasing tidal volume and resp rate
-high levels of nitric oxide in blood to dilate vessels enhancing o2 delivery
-have a different variant of the hypoxia inducable transcription factors genes
-increased hb
-larger chest dimensions
-increased pulmonary artery pressure
