1. Intro

Question 1

At which vertebral level is each kidney located?

Answer 1

Left - T11 to L2.

Right - T12 to L3.

Question 2

What are the 4 functions of the kidneys?

Answer 2

Regulation - controls the concentrations of key substances in extracellular fluid (influencing intracellular fluid).
Excretion - excretes waste products.
Endocrine - synthesis of renin, erythropoietin, prostaglandins.
Metabolism - activate vitamin D, catabolism of insulin, calcitonin.

Question 3

What is the normal osmolality of plasma/interstitial fluid/intracellular fluid?

Answer 3

280-310 mmol/L.

Question 4

What ions is osmolality in extracellular fluid determined mainly by?

Answer 4

Na+ and Cl-.

Question 5

What ions is osmolality in intracellular fluid determined mainly by?

Answer 5

K+.

Question 6

What are the consequences of the kidneys failing to control ECF volume and osmolarity?

Answer 6

Volume - changes in BP, tissue fluid, cell function.

Osmolarity - cells shrink or swell.

Question 7

How do the kidneys contribute to acid base balance?

Answer 7

Regulate the concentration of bicarbonate in plasma.

Question 8

What is ultrafiltrate?

Answer 8

Water, ions and all small molecules that the kidneys filter.

Question 9

What volume of ECF is filtered per day by the kidneys?

Answer 9

180L/day.

Question 10

On average, what volume of urine if produced by the kidneys per day?

Answer 10

1.5L.

Question 11

How many nephrons are in each kidney?

Answer 11

1.5 million.

Question 12

Through what areas of the nephron does filtrate pass?

Answer 12

Glomerulus, proximal convoluted tubule, loop of Henle, distal convoluted tubule, connecting tubule, collecting duct.

Question 13

What proportion of cardiac output goes to the kidneys?

Answer 13

22%.

Question 14

What part of the nephron is the major site of reabsorption?

Answer 14

Proximal convoluted tubule.

Question 15

What property of the epithelial cells lining the tubules of the nephrons allow transport across the epithelium?

Answer 15

Epithelial cells are polarised.

Question 16

Movement of what ion across the basolateral membrane of the tubular epithelium provides energy for the reabsorption of other substances eg glucose?

Answer 16

Na+.

Question 17

What is the main function of the loop of Henle?

Answer 17

Create a gradient of increasing osmolarity in the medulla by counter-current multiplication.

Question 18

Where in the tubule does the most variable reabsorption of electrolytes and water take place?

Answer 18

Distal convoluted tubule.

Question 19

What is diuresis?

Answer 19

Production of large volumes of dilute urine.

Question 20

What is the main function of the collecting duct?

Answer 20

Water reabsorption down the osmotic gradient as it passes through the high osmolarity environment of the medulla.

Question 21

What hormone is variable sodium recovery in the nephron controlled by?

Answer 21

Renin angiotensin system.

Question 22

What hormone is variable water recovery in the nephron controlled by?

Answer 22

Anti diuretic hormone.