Respiratory System - o2 & co2 Flashcards
The diffusion gradient of O2 in alveolar air is
High
Low in alveolar blood capilliaries
The diffusion gradient of CO2 in alveolar capillaries in the blood is
High
Low in alveolar air
percentage of oxygen in atmospheric air?
~21%
= 160mmHg
The concentration of gases is known as
Partial Pressure
The Partial Pressure of oxygen is PO2
The direction of movement gases is determined by
partial pressure differences of gases in alveoli and in the blood
What is arterial blood?
Blood that is leaving the lungs to return to the heart
Has lost CO2 and picked up O2
A litre of arterial blood contains
200ml O2
200ml of O2 in arterial blood - split
O2 dissolved in water - 3ml/litre
O2 bound to Hb in RBC - ~197ml/litre
The main factors determining the level of saturation of Hb with O2 is
PO2 level in blood
Increasing PO2 blood increases
the amount of O2 bound to Hb
The relationship between Hb saturation and Po2 is shown by the
Oxygen-haemoglobin dissociation curve
When PO2 is low, O2is
not bound to Hb (it is released from Hb)
The dissociation curve can be influenced by
pH
Temperature
Metabolites
Right shifts of the dissociation curve
acidosis
increased PCO2
Increased metabolites (by-products of metabolism)
hyperthermia
Left shifts of the dissociation curve
Alkadocis Decreased PCO2 Hypothermia decreased metabolites foetal Hb
