Respiratory L5.2 Flashcards
1) What is the effect of high altitude on oxygenation?
1) PO2 reduced, less driving force O2 to bind to Hb in lungs
2) Blood passing lungs less saturated with O2 = hypxemia
3) Pulmonary hypoxia.
How does being at high altitude lead to respiratory alkalosis?
- low pO2
- Hypoxaemia
-Increased ventilation by chemoreceptors in caorotid bodies - ypoxia-driven hyperventilation causes excess loss of CO2
resulting in respiratory alkalosis.
1) What is resp alkalosis?
1) the amount of
CO2 in blood drops to a level below normal range.
State symptoms of resp alkalosis
Hyperventilation
Dizziness
Light headedness
Confusion
How does resp alkalosis affect O2 dissociation curve?
Alkaemia shifts the hemoglobin O2 dissociation curve to
the left, impairing O2 delivery to the tissue.
What is the main cause of resp alkalosis?
What are the two types of resp failure?
1) What is the initial response to rapid ascent?
1) Rapid ascent to 2000m or higher stimulates sympathetic nervous sysem.
2) Increased heart rate + cardiac output, mildly increase BP
Also leads to PULMONARY HYPOXIA:
-PO2 in alveoli decreased at ascent
- In response to pulmonary hypoxia, pulmonary vasoconstricton occuts, makes hypoxeamia worse
-pulmonart vasoconstrciton increases pulmonary arterial hypertension
1) What is chronic respiratory alkalosis?
2) How does metabolic compensation occur in chronic resp alkalosis?
1) Condition present 7 days or more.
2) Full compensation occurs. METABOLIC COMPENSATION
3) METABOLIC COMPENSATION: Kidneys icnrease H+ retention and bicarbonate excretion
This gives metabolic acidosis that compensates rep alkallosis.
Compensation 7-10 days
Mechanism of acclimatisation
What happens during acclimatsiation?
What are the three components to correct respiratory alkalosis?
How does metabolic acidosis compensate chronic resp alkalosis?
- initially low PO2
-Increases rate, depth breathing
-blows off excess CO2
-alkalosis
-High pH inhibits central chemoreceptors
-causes breathing to decrease
-hypoxaemia
-Kidneys respond tto this by increasing bicabronate excretion
-decreases acid excretion
-metabolic acidosis
-counteracts resp alkalosis
-restores pH
How does an increase in erythrocyte number (polychythemia) compensate resp alkalosis?
What could be an issue if haemtocrit gets too high?
- Hypoxaemia stimulates interstitial cells in kidney to raise EPO production
2) Increases RBC production
3) Increases haematocrit
4) increase the oxygen carrying capacity of the
blood.
Functional limit to max haematocrit. Increased haemtocrit, increases blood viscocity. Increases pulmonary vascular resistance. Pulmonary artertial hypertenstion. Right heart failure
Describe how reduced pulmonary vascular resistance compensates resp alkalosis
- Pulmonary vascular reistance falls
- Reduced hypoxic vasoconstriction
- Due to increased synthesis of nitric oxide in pulmonary endothelium
Describe how resp alkalosis alters metabolism and functions in the body
Leads to hypokalemia. Decreased H+ excretin= other ions take the place of H+. Often potassium. Too much potassium = hypokalemia
State signs and symptoms of acute mountain sickness
What do we use to prevent and treat AMS?
Where is CA found?
Acetazolamide
Carbonic Anhydrate inhibtor
Increases bicarbonate excretion
Produces meteabolic acidosis.
CA found at PCT in kidney
Which area of the brain is the priamry motor cortex found in?
FRONTAL LOBE
Area 4
Anterior to central sulcus
CONTROLS VOLUNARY MNOVEMENT
Voluntary diaphragmatic motion = near area responsible for hand motion
