Physiology 4 Flashcards
What is Henry’s law?
The amount of a given gas dissolved in a given type of liquid (e.g. blood) at a constant temperature is proportional to the partial pressure of the gas in equilibrium with the liquid
What is the partial pressure of a gas in solution equal to?
Its partial pressure in the gas mixture with which it is in equilibrium with
What are the 2 mechanisms by which oxygen is carried by the blood?
Physically dissolvedOxygen bound to haemoglobin (98.5% of O2 carried in this way)
How many ml of O2 is normally carried in 1L of blood?
200ml (at a normal arterial PO2 of 13.3kPa and a normal haemoglobin concentration of 15g/ 100ml
How many harm groups does each haemoglobin contain?
4
How many oxygens does each haem group reversibly bind?
1
When is haemoglobin considered as fully saturated?
When all the Hb present is carrying its maximum O2 load
What is the primary factor which determines the percentage saturation of haemoglobin with O2?
PO2
What is Hb made up of?
2 alpha chains2 beta chains4 harm groups each with an iron which binds 1 O2
What is the normal PO2 at pulmonary capillaries?
13.3 kPa
What is the average resting PO2 at systemic capillaries?
5.3kPa
What shape does an oxygen haemoglobin dissociation curve have?
A sigmoid shape
What does the cardiac index do?Units?
Relates the cardiac output to the body surface areaL/min/metre2Normal range is between 2.4 - 4.2 L/min/metre2
What are the units of the oxygen delivery index? (DO21)
ml/min/metre2
What are the units of the oxygen content of arterial blood?
ml/L