Respiratory physiology 2 Flashcards
What is ventilation?
Gas exchange between alveoli and atmosphere
What is external respiration?
Passive diffusion of O2 and CO2 between alveoli and blood in pulmonary capillaries
Converts deoxygenated blood to oxygenated blood
What is gas transport?
O2 and CO2 carried in blood between alveoli and tissues
What is cellular respiration?
O2 utilisation and CO2 production by tissues
What are conducting airways?
Tidal flow, air moves in and out following muscle contraction
How many respiratory branches are there?
23
What are the first 16 respiratory branches?
Conducting airways
What are the last 7 respiratory branches?
respiratory exchange - passive diffusion driven by partial pressure gradients
What is Dalton’s law?
How gases move down their concentration gradient by diffusion
What is Henry’s law?
How the solubility of a gas relates to its diffusion
Quantity of gas dissolved in a liquid is directly proportional to partial pressure of a gas
Solubility of a gas
Higher partial pressure and higher solubility of gas means more gas will stay in solution
What is partial pressure?
pressure exerted by a gas in a mixture
How to calculate partial pressure?
percentage in mixture x ambient pressure
What is internal respiration?
Exchange of O2 and CO2 between systemic capillaries and tissues cells
Converts oxygenated blood into deoxygenated blood
Hb + O2
Hb-O2
Structure of haemoglobin
Globin protein (4 polypeptides, 2 alpha and 2 beta) 4 haem groups
Why does the Hb-O2 saturation curve have a specific shape?
Initial binding of oxygen is difficult
After first molecule has bound. binding the next two is easier
As sites get occupied, saturation is harder to reach
What is the Bohr effect?
In tissues that need more O2, the curve shifts to the right to aid unloading of O2
Equation for Bohr effect
CO2 + H2O -> H2CO3- + H+ + HCO3-
What does H+ do to Hb?
Binds and decreases its O2 carrying capacity
Why is foetal Hb good?
Higher affinity for oxygen
How is most carbon dioxide stored?
HCO3-
Haldane effect
In tissues, Hb gives up O2
Affinity for CO2 increases
Greater CO2 carriage
In lungs, Hb gives up CO2
Affinity for CO2 decreases
Hb binds O2
What does higher pp of CO2 mean?
Spinal fluid is more acidic - activates chemoreceptors
CO2 in RBC
- CO2 enters RNC to form bicarbonate
- To maintain electrical balance, Cl- moves inside cell (chloride shift)
- CO2 is removed and transported as bicarbonate inside RBCs
- CO2 joins amino groups to form carbamino compound
- More CO2 removed
- Both generate H+ that need to be buffered by amine compound in Hb (Bohr effect means it decreases ability of Hb to bind with oxygen )
- Amount of CO2 influenced by saturation of Hb with O2
