Flashcards in PSL301: Respiratory 6 Deck (56)
what is considered high altitude?
> 1500 m
main problem at high altitudes?
What is the partial pressure of O2 in dry air?
253 x 0.21 = 53 mmHg
How does the peripheral chemoreflex respond to hypoxia?
- Will increase ventilation rate faster
- more dramatic increase
- begin responding at lower pCO2 levels
What happens to the hemoglobin saturation curve when hyperventilating?
- CO2 decreases
- H+ decreases
- pH increases (basic)
- more O saturation at tissues (does not release)
long term consequences of hypoxia
- release of erythropoietin
- synthesis of 2,3-DPG in RBC
What effect does 2,3-DPG have on the hemoglobin saturation curve?
- Hb has less affinity for O2
2,3-DPG is an intermediate of the ___ pathway
When does 2,3-DPG degrate?
When blood is stored
What conditions are related to high altitude? Which are very serious?
1. mountain sickness
2. high altitude pulmonary edema **
3. high altitude cerebral edema **
mountain sickness symptoms
symptoms of mountain sickness is caused by...
cerebral autoregulation of blood flow
symptoms of high altitude pulmonary edema
- swelling of lungs
- shortness of breath
- cough pink frothy fluid
high altitude pulmonary edema
hypertension in the lungs
high altitude cerebral edema
swelling of the brain
high altitude cerebral edema symptoms
- coma & death (due to capillary leakage)
- brain swelling
- herniation of brain through the tentorium
herniation of brain through the tentorium
brain is pushed out through a hole towards the cerebellum if swelling is severe
cannot control muscles
what happens during pulmonary edema?
Normally, lungs vasoconstrict blood vessels around aveoli that have low pO2 and pCO2 to increase efficiency. At high altitudes, all alveoli have low pO2 and pCO2 so all blood vessels become constricted.
- increased blood pressure
- pushes fluid out of vessels
- fluid surrounds alveoli, making it harder for gas exchange
prevention of hypoxia
what does acetazolamide do?
- stops CA enzyme
- diuretic: reduce fluid in body
- forces the kidneys to excrete bicarb: want less alkaline conditions
treatment for hypoxia
- go to lower altitude
- give O2
treatment for cerebral edema
treatment for pulmonary edema
Nifedipine: lower pulmonary artery pressure by blocking L-type Ca++ channels
what happens to oxygen levels during exercise?
increases (log graph), then plateaus high for duration of exercise
What happens to oxygen levels at the end of exercise?
Rapid decrease (hyperbola)
what is used to deliver more oxygen to muscles during exercise?
respiratory & cardiovascular systems
What is the limiting factor during exercise?
What components of the respiratory system is affected during exercise?
- breathing frequency