Waikato Course Flashcards
What is Henry’s law
At constant temp, the amount of gas dissolved is proportional to the partial pressure of that gas.
Which form of iron is found in Hb?
Fe2+
Distinct points on the oxygen dissociation point
- Arterial
- Venous
- ICU
- P50
100, 98
60, 91
40, 75
26.6, 50
What is the O2 content of artery / vein
20 ml/dL
15 ml/dL
What is 2,3 DPG
a metabolic biproduct of anaerobic metabolism, particularly in red blood cells.
2,3 DPG production is increased in hypoxia
Increases O2 unloading from Hb to tissues.
Why is the [HCO3] higher, and [Cl] lower in venous blood compared to arterial blood
Due to Hamburger effect and CO2 buffering by bicarbonate system.
Increased CO2 -> increased HCO3 inside cells -> chloride shift
What happens when efferent arteriole is constricted?
Increased tone - two competing effects
- Decreased renal blood flow
- Increased hydrostatic pressure in glomerulus
Overall, effect depends on the degree of increased tone
- Mild tone increase -> slight increase in GFR
Large increase -> significant decrease in RBF and reduces GFR
What is the effect of ATII on GFR
Primarily acts on efferent than afferent arteriole
- Decrease renal blood flow
- Increase filtration fraction
Normovolaemic person lands on the decreased GFR / RBF
In hypovolaemia, ATII constricts efferent arterial, and prostaglandin will dilate the afferent to maintain blood flow
- Crucial to maintain GFR
Also allows more water reabsorption in tubules
Define potency
Drug dose required to achieve a response.
Related to affinity and pK
What is affinity
Ability for a ligand or a drug to bind to the receptor
Explain the effect of giving morphine and buprenorphine together
Low dose agonist- additive effect
High dose agonist - reduced maximal efficacy due to receptor occupation.
Define time constant
The time for an exponential process to reach completion if the initial rate of change remains constant.
T1/2 = time constant x 0.693
Time constant = T1/2 / 0.693
What is the difference between half life vs half time
Half life - model of what happens in a single compartment
Half time - multi compartment model, half life is not applicable, so use half time instead.
Define T1/2 Ke0
time required for the effect site to reach 50% of the plasma concentration
What is the normal: GFR (per min vs per day) Plasma volume Renal plasma flow Filtration fraction
125ml/min or 180L/day
3L
600 ml/min
~20%
