Ventilation and Acid Based Balance Flashcards
What is partial pressure?
Pressure exerted by each individual gas in a mixture of gases. When a gas is dissolved in a liquid, the amount dissolved depends on partial pressure.
Describe pulmonary gas exchange?
Cells use oxygen to make energy and produce carbon dioxide as waste. blood transports oxygen and carbon dioxide in and out of the bloodstream. Oxygenation is the transfer of oxygen from alveolar to blood stream
Explain oxygen transport and the oxygen-haemoglobin dissociation curve
O2 is bound to haemoglobin to make oxyhaemoglobin.
Sao2 is the number of haemoglobin molecules bound to o2. Up to 4 o2 mols can bind to a haem.
Once one o2 has bounded to haemoglobin, it makes it easier for more to bind.
Changes in co2 levels and hydrogen affect the rate and depth we breathe.
Co2 elimination is determined how quickly it can be removed from bloodstream to alveoli.
what factors shift the dissociation curve to the left?
increase ph, decrease paco2, decrease temp, decrease DPG (enzyme)
What factors shift the dissociation curve to the right?
decrease ph, increase paco2, increase temp, increase DPG (enzyme)
what can increased RR cause?
it can cause hyperventilation where we are trying to get rid of co2 from the body that chemoreceptors have picked up, so there are increased co2 levels in blood
What happens to some patients who of chronically increase co2 levels. e.g COPD ?
They rely on decreased oxygen to innervate them to breathe (hypoxic drive).
Clinically, if we increase oxygen, they will decrease the feedback loop and will not be able to breathe.
What are the three homeostatic mechanisms that achieve acid base balance?
1) buffer systems (secs)
2) resp systems (1-15mins)
3) Metabolic systems(days)
Explain the buffer systems role is managing deviations from normal in acid based balance.
It is activated in secs.
Achieved by balancing hydrogen ions. Carbon dioxide dissolves in water and makes bicarbonate. Hydrogen=more acididc=bicarbonate. HCO3 accepts hydrogen, so hydrogen decreases in blood.
Explain the respiratory systems role in deviations from normal in acid base balance
activated in 1-15 mins.
If buffering is not adequate, the lungs regulate co2 levels.
Explain how metabolic mechanisms help with acid based homeostasis
Kidneys excrete metabolic acids and excrete hydrogen in the urine. Kidneys can reabsorb bicarbonate from urine, which decreases hydrogen circulating in the blood.
