wk 10 lec 2

Question 1

volatile vs non volatile acids

Answer 1

volatile= can breath off as carbon dioxide
- via bicarbonate buffer (non volatile can also be buffered by bicarbonate to minimize large pH changes but cant breath off- still need to secrete protonated part via kidneys)

non volatile- cant breath off

Question 2

examples of nonvolatile acids

Answer 2

lactic acid, ketone bodies, sulphuric acid, HcL from protein metabolism or consumptions

Question 3

orange juice vs cranberry juice acids

Answer 3

cranberry- non volatile bc benzoic acid

orange juice is citric acid which turns into citrate into CO2 so its volatile

Question 4

3 mechanisms of hydrogen ion regulation

Answer 4

1. fluid chemical buffers (IC and EC)
   –> rapid: bicarbonate, phosphate, ammonia, proteins
2. respiratory system
   –> rapid, Co2, NOT nonvolatile
3. renal system
   –> slower, non-volatile, secrete H+, reabsorb and generate new HCO3-

Question 5

phosphate, proteins, bicarbonate, ammonia

where are theses buffer systesm

Answer 5

phospahte: renal tubular

proteins: intracellular (i.e. hemoglobin)

bicarbonate: ECF

ammonia: renal tubular

Question 6

protein intraceullar buffer

Answer 6

donate or accept amino acids (bind or release H+)

Question 7

most important amino acids at physiological pH

Answer 7

histidine and cysteine

Question 8

why is hemoglobin a good intraceullar buffer

Answer 8

38 histidine residues

carries CO2 through blood when O2 is low

move co2/hco3 across RBC membrane

Question 9

phosphate buffer system for

Answer 9

intraceullar buffer

urinary buffer to stabilize pH

Question 10

most important ECF buffer

Answer 10

bicarbonate

Question 11

normal values for HCO3- (bicarb), CO2 and pH

Answer 11

HCO3= 24 (22-26)
CO2= 40 (35-45)
pH= 7.40 (7.35-7.45)

Question 12

what to carry H+ out into urine

Answer 12

ammonia (regulated)

also a bit of phospahte

Question 13

where is ammonia made

Answer 13

proximal tubule

then secreted into tubular urine

Question 14

ammonium reaborbed

Answer 14

NH4+ reabsorbed in thick ascending limb

Question 15

pH of tubular urine along tubule

what happens in collecting duct and via what

Answer 15

continues to decrease (get more acidic)

NH3 goes into acidic collecting duct and trapped as NH4+ and eliminate H+

Question 16

how does 80% of HCO3 get reabsorbed in proximal tubule

Answer 16

not directly (bc not permeable to luminal membranes)

combines with H+ to make H2CO3 via carbonic anhydrase and then dissociate to CO2 and H2o

then secrete H+ via Na/H countertrasnprot

Question 17

production of new HCO3 via what amino acid and what process

Answer 17

in PCT make new bicarbonate and ammonia

from glutamine metabolism

ammonia to carry H+

gluconeogenesis – PEP from
glutamine is converted to
glucose

Question 18

how to excrete lots of acid at pH of 4.5 and not too acidici

Answer 18

buffer with phospahte and ammonium

Question 18

how to make urine acidic

which ion
which part

Answer 18

in collecting duct

H+ ATPase

and H2CO3 dissociate to HCO3 and H+

Question 19

produce ammonium if ECF to acidic. where

Answer 19

PCT

Question 20

urinary buffer

Answer 20

ammonia in PCT (to balance H+)

Question 21

alpha and beta intercalated cells in collecting duct impacts

Answer 21

alpha (acidosis) secret H+, reabsorb HCO3- (and exchange K+ for H+ too)

beta (alkalosis): secret HCO3, absorb H+

Question 22

acidosis vs alklosis

Answer 22

acid:: <7.35 pH
alk: >7.45 pH

Question 23

respiratory acidosis

examples

Answer 23

pCO2 >45

hypoventilate –> decrease pH

not exhaling CO2 enough

apnea, obstructive lung disease, V/Q mismatching, right to left shunts

Question 24

respiratory alkalosis examples

Answer 24

pCO2 <35mmHg hyperventilate --> increase pH anxiety, aspirin, stroke, oxygen deficiency from high altitude or pulmonary disease

Question 25

metabolic acidosis causes

Answer 25

low pH from loss of HCO3- or cant deal with new non-volatile acids kidney failure to excrete metabolic acids (renal tubular acidosis) form excess metabolic acids (diabetes, lactic acid) add metabolic acids via ingestion (aspirin) loss of base from body fluids (diarrhea, vomit)

Question 26

metabolic alkalosis examples

Answer 26

increase HCO3- (or loss of H+) diuretics, excess aldosterone, vomit, alkaline drugs

Question 27

how do kidneys and lungs response if respiratory or metabolic alkalosis/acidosis

Answer 27

i.e. if respiratory acidosis then kidneys will excrete more H+ respiratory alkalosis then kidneys increase HCO3- excretion ie. if metabolic acidosis alveolar hyperventilate so kidneys can increase H+ excretion

Question 28

anion gap

Answer 28

normal: 10-12mmol/L from Cl- and HCO3- to find cause of metabolic acidosis --> if too high might have too many acids i.e. ketones, lactate, salicylates (conjugate bases)

Question 29

causes of normal and high anion gap for metabolic acidosis

Answer 29

normal: diarrhea, renal tubular acidosis high: uremia, lactic acid, ketoacidosis, methanol intoxication

Question 30

where is most of potasium

Answer 30

intracellular dont want extraceullarl

Question 31

what 5 things shift potassium into cells

Answer 31

insulin (via Na+/K+ pump post prandial) aldosterone beta-adrenergic stimulation (NE, and epinephrine increase NA/K pump) acid base imbalance (alkalosis shift K+ into cells, acidosis is out) hyperkalemia (an increase in K+ in ECF shifts in via na/k pump)

Question 32

what 3 things shift potassium out of cell

Answer 32

cell lysis strenuous exercise increase ECF osmolarity acidosis

Question 33

early vs late K+ shifts

Answer 33

early: Na/K pump activated by insulin, catecholamines, aldosterone late: aldosterone via principal cells for renal excretions of K+

Question 34

PCT absorbption of k+

Answer 34

65%

Question 35

K+ handing in tubules

Answer 35

reabsorb 90% in distal nephron secrete it depending on aldosterone and pH

Question 36

K+ in PCT

Answer 36

reabsorb, link to Na+ and H2O (solvent drag) ROMK channel on basolateral side --> via decerase intraceullar ATP --> also increase Na/K pump

Question 37

K+ in thick ascending limb

Answer 37

K+ and Cl- permeable, paraceullar NKCC channel pull K+ into cell

Question 38

K+ in dif parts of tubule

Answer 38

PCT- ROMK channel thick ascending limb: NKCC channel distal: principal cells and alpha itnercalated, ENaC channel

Question 39

K+ in distal nephon

Answer 39

principal cells aldosterone fro K+ secretion and Na+ reasborb increase ENaC, Na/K pump KCC transporter alpha intercalated cells rescue K+ if hypokalemia (H+/K+ countertrasnport via ATP, alkalosis)

Question 40

potassium excretory region

Answer 40

Most daily variation in potassium excretion is caused by changes in potassium secretion in distal convoluted tubule and early collecting tubules/ducts

Question 41

cells for K+ and Na+ fine-tune via aldosterone

Answer 41

principal cells in collecting duct also alpha intercalated cells

Question 42

luminal Na+ and K+ secretion

Answer 42

principal cells secrete K+ and absorb Na+ in collecting duct

Question 43

increase K+ secretion

Answer 43

osmotic diuresis, volume expansion, loop diuretics

Question 44

Na+ depreviation

Answer 44

increases aldosterone secretion but K+ doesnt drop that much because theres decreasedGFR --> slow tubular fluid delivery --> less K+ washout

Question 45

pH impacting K+

Answer 45

alkalosis increases K+ transport into cells (hypokalemia) acute acidosis reduced K+ secretion, but chronic increases it