Biochemistry of Lungs Flashcards
What is pulmonary ventilation
Process of breathing I.e inspiration and expiration
What does Boyle’s law state
The volume of gas is inversely proportional to its pressure if the temperature and number of particles are constant
What is Dalton’s law
The pressure of each gas is independent of the others and is directly proportional to its concentration
What is external respiration
The exchange of gases between lungs and blood
how are gases exchanged across the membrane
Due to pressure gradients and diffusion
What is henry’s law
Amount of dissolved gas in a liquid is proportional to its solubility
How many ml of O2 does 1L of blood contain
200ml
Two forms of haemoglobin
Deoxyhaemoglobin - Hb
Oxyhemoglobin - HbO2
How many subunits does haemoglobin contain
4 globin subunits
What is oxygen saturation
Measures how much Hb is currently bound to O2 vs unbound
What is the partial pressure of oxygen when body is functioning normally
75-100mmHg
What does increased cellular metabolism result in
Increased thermal energy produced Energy released into the capillaries Increased temperature in the blood More oxygen required to do work Hb binding to O2 with a lower affinity Increased O2 unloading at the tissues
What does 2,3-diphosphoglycerate do
Binds with higher affinity to deoxy Hb, decreasing Hb’s affinity for O2
Promotes release of any remiaining O2 molecules bound to the Hb
Results in rightward shift of the O2 dissociation curve
How is Co2 transported in blood
10% dissolved in plasma
30% bound to Hb
60% buffered with H2O as carbonic acid
Cellular respiration produces
How much CO2
200ml/min
Explain CO2 transport in the Bohr effect
Cells convert the CO2 to H+ and HCO3- using carbonic anhydrase
Increased H+ conc., decreases pH
H+ binds to Hb allosterically
Decreases its affinity for O2 causing more O2 release
Where are the peripheral chemoreceptors located
Carotid and aortic bodies
What are the peripheral chemoreceptors sensitive to
Large changes in PO2 as the blood leaves the heart
Where are the central chemoreceptors located
Medulla oblongata
What are the central chemoreceptors protected by
Blood brain barrier
What do the central chemoreceptors detect
Indirectly detect changes in PCO2 and H+ in the blood
What does increased PCO2 lead to
Increased ventilation
What does Arteirial blood gas do
Measures acid-base levels
Can help evaluate respiratory system function and body’s ability to maintain homeostasis
What can ABG be used to diagnose
Asthma
COPD
Kidney failure
Heart failure
