Lecture 35. Extreme Breathing Flashcards
What is the concentration of O₂ 100,000 feet up?
Constant 21%
What is Dalton’s Law?
The pressure of a mixture of gases equals the sum of pressures that each gas would exert if it occupied alone the space filled by the mixture
What is the onset of hypoxia associated with?
Mildly euphoric state, rapid loss of critical judgement, slowed thinking and muscular weakness
What is affected by high altitude hypoxia?
Physical performance
Mental performance
Sleep
What does hyperventilation reduce?
Reduces PCO₂ blood
This results in blood and CSF becoming more alkaline
HCO3⁻ is moved out of CSF to blood
Over 2-3 days kidneys excrete HCO3⁻ to move the balance closer to normal
What are examples of high altitude diseases?
Acute Mountain Sickness
High Altitude Pulmonary Edema
High Altitude Cerebral Edema
What are symptoms of acute mountain sickness?
Headache, breathlessness, fatigue, insomnia, nausea
Some evidence of mild brain swelling
Begins 2-3 hours after ascent
Last 2-3 days
Descent to low altitude rapidly reverses symptoms
What is acetazolamide?
A carbonic anhydrase inhibitor
This increases excretion of HCO3⁻ helping to reduce alkalosis
What are the symptoms of high altitude pulmonary edema?
Laboured breathing, reduced exercise tolerance
Dry cough that may give frothy blood stained sputum
Rapid breathing and heartbeat
Raised body temperature
What are the symptoms of high altitude cerebral edema?
Confusion, rapid mood changes, hallucination
Loss of control of body movement
Coma
Only rapid descent will cure this
Potentially fatal
What do birds have?
Uniquely thin blood gas barrier
What is Cx26?
A CO₂-gated receptor that releases ATP
What do elephants not have?
A pleural space
In elephants the pleural space is filled with dense connective tissue
What is the pleural space in mammals lubricated by?
Pleural fluid so that the two faces of the pleura can slide past each other
This fluid is derived from microvessels which are fragile
