measuring GFR and base balance

Question 1

what makes GFR equivalent to the clearance of a drug

Answer 1

known amount of plasma and
not metabolised
not absorbed or secreted
excreted unchanged in urine

Question 2

how to assess GFR

Answer 2

look at concentration of nitrogenous waste products in the blood

Question 3

what are 2 nitrogenous waste products

Answer 3

creatine and urea

Question 4

characteristics of creatine

Answer 4

synthesised at a continual steady rate
production not influenced by many factors
freely filtered in glomerulus
no reabsorption
no secretion

Question 5

what happens to creatine when GFR is reduced

Answer 5

less creatine excreted and will accumulate in plasma

Question 6

characteristics of urea

Answer 6

main waste product of animals
water soluble
v small molecule
partially fat soluble
freely filtered through glomerulus

Question 7

where is urea synthesised

Answer 7

liver

Question 8

lipid solubility of urea

Answer 8

moderate lipid soluble

Question 9

what is azotaemia

Answer 9

increased nitrogenous waste products in the blood
marker of decreased GFR

Question 10

what type A intercalated cells are active on the apical membrane of the DCT

Answer 10

H+ ATPase
H+K+ ATPase

Question 11

what are protons and bicarbonate formed from

Answer 11

dissociation of carbonic acid

Question 12

what do protons that have been pumped into urine bind to

Answer 12

bicarbonate buffers

Question 13

intercalated B cells on basolateral membrane

Answer 13

H+ ATPase
H+K+ ATPase

Question 14

when do type A intercalated cells in the DCT work

Answer 14

increased H+ in interstitial space
=acidosis

Question 15

when do type B intercalated cells in the DCT work

Answer 15

when H+ decreased in interstitial space
= alkalosis

Question 16

what is pH

Answer 16

a measure of the concentration of protons

Question 17

what does metabolism result in

Answer 17

production of protons

Question 18

what is the single biggest input of protons under normal conditions

Answer 18

metabolic CO2

Question 19

what do buffer systems do

Answer 19

act quickly to temporarily bind excess H+ or OH- hiding the highly reactive ions until they can be permanently secreted.

Question 20

what does changing the rate and depth of breathing do

Answer 20

CO2 is exhaled or retained and blood pH is corrected

Question 21

limits of respiratory system for correction of acid-base balances

Answer 21

only functions when respiratory system and control centres working normally
availability of bicarbonate ions
cannot protect ECF from pH changes due to increased or depressed CO2 levels (cannot buffer itself)

Question 22

slowest mechanism

Answer 22

kidney excretion/reabsorption of acidic ions or basic ions

Question 23

what is respiratory acidosis

Answer 23

when CO2 accumulates because of hypoventilation

Question 24

what is metabolic acidosis

Answer 24

occurs whenever non-respiratory acids accumulate or the acid load normal but bicarbonate deficient.

Question 25

metabolic reasons for acidosis

Answer 25

diabetic ketoacidosis
kidney disease
severe faecal loss of bicarbonate during diarrhoea

Question 26

respiratory reasons for acidosis

Answer 26

remove CO2 at a lower rate than it is being produced
pneumonia

Question 27

metabolic reasons for alkalosis

Answer 27

persistent vomiting
upper GI obstruction

Question 28

respiratory reasons for alkalosis

Answer 28

lungs remove CO2 at a faster rate than its being produced
hyperventilation