Renal System

Question 1

Answer 1

The dissociation constant is the concentration of products discoated divided by the concentration of products associated

Question 2

A weak acid is…

Answer 2

Less dissociated

Question 3

Acid is produced…

Answer 3

Continuously in physiology and this threatens blood pH (therefore protein structure and function)

Question 4

Volatile acids is….

Answer 4

CO2 which is produced via our metabolic system. This combines with water to produce carbonic acid.

Question 5

Non volatile acids…

Answer 5

Comes from incomplete carbohydrate metabolism e.g. Sulphuric acid or Hydrochloric acid

Question 6

Non volatile acid production is around

Answer 6

70mM/day through metabolism

Question 7

Guardians of blood pH are

Answer 7

Chemical buffering (which minimized the change in pH) - conducted by bicarbonate, phosphate and proteins

Respiratory response (e.g. chemoreflex which increases respiratory rate: CO2 loss, which decrease carbonic acid concentration)

Renal response (slow) - ensures excess proteins are removed from the body

Question 8

Renal regulation of Acid- base occurs via…

Answer 8

1. Excretion of protons (with urinary buffers)
2. Reabsorption of filtered HCO3
3. Bicarbonate regeneration (production of new bicarbonate - most challenging part of renal response)

Question 9

Kidneys can also remove

Answer 9

bases (via HCO3 secretion)

Although the usual challenge is to remove excess acid

Question 10

Excretion of protons (H+)

Answer 10

Very little H+ is secreted as free H+. The max uriniary acidifacation is around pH OF 4.5 (1000x the gradient of H+/ATPase)

pH 4.5 = 0.03 mmol/l = <1% of acid load produced everyday

Excretion of protons can occur via binding to tritatble acid (equates to around 30%) or ammonium (70%)

Question 11

Tritatable acid works via

Answer 11

allowing phosphates to bind to hydorgen ions. Creatine can also be used

Question 12

Ammonia can work via

Answer 12

having ammonia produced in the kidney, with the pka of reaction being 9.0, therefore the ammonia is able to convert to ammonium fairly quick, which is then secreted via our urine.

Question 13

As urine moves along nephron

Answer 13

Filtered bicarbonate is reabsorbed, tritatable acids are formed and excreted, NH4 is formed and excreted.

Question 14

The proximal convulated tubule is where

Answer 14

Sodium channels are on the apical side of the membrane which absorb sodium but release hydrogen in exchange

Question 15

At the cortical collecting tubule you have…

Answer 15

Hydorgen pumps and sodium/hydrogen symport like pumps as well on the apical side but carbinic acid is transported from the basal membrane side.

Carbon dioxide and water reacts to produce hydrogen ions and carbonic acid.

Question 16

Excretion of Hydrogen ions happens with

Answer 16

Urinary buffers

Question 17

An upregulation of glutamine in the proximal tubule

Answer 17

is involved in the production of new HCO3

Question 18

Fanconi syndrome is

Answer 18

A generalised proximal tubule impairment - causing acidosis

Question 19

The cortical collecting tubule has

Answer 19

A principal cell, (Na/k)

and an intercalated cell (acid/base)

Question 20

Carbonic anhydrase deficiency is where…

Answer 20

Acidosis occurs. If the cause is genetic, it is known as type 2 renal tubule acidosis

Question 21

Distal Tubule is where there are

Answer 21

mutations in the H+/ATPase or in the AE1 (basolateral HCO3 exit pathway)