Renal Physiology II

Question 1

What are the two different types of nephron?

Answer 1

Cortical nephrons and Juxtamedullary nephrons

Question 2

What type of nephron has a glomerulus further away from the corticomedullary junction?

Answer 2

cortical nephrons

Question 3

Where does the vast majority of water and solute reabsorption occur?

Answer 3

In the proximal convoluted tubule

Question 4

What are the 3 different ways solutes/ water are reabsorbed in the PCT?

Answer 4

Primary activate transport, e.g ATPase/ Na+ pump
Secondary active transport e.g following an electrochemical gradient
Simple diffusion

Question 5

What are some adaptations of PCT cells to allow for reabsorption?

Answer 5

They have a brush border which increases their surface area and mitochondria which gives them energy for active transport

Question 6

What are the two different types of cell found in the collecting duct?

Answer 6

Principal cells and intercalated cells

Question 7

What is the renal threshold?

Answer 7

the reasorptive capacity of the kidneys

Question 8

What are the two ways that water can be reabsorbed?

Answer 8

Paracellularly (through tight junctions between cells) or transcellularly ( through cells via special channels)

Question 9

How does the counter-current multiplier system work?

Answer 9

Ions are actively pumped out of the ascending limb making the medulla salty
this means that water passively moves out of the descending limb
These are the all absorbed by the peritubular capillaries

Question 10

How does reabsorption work in the PCT?

Answer 10

Sodium is actively pumped out of the Tubular cells and Potassium is actively pumped into the tubular cells
High intracellular potassium means that potassium diffuses out
This causes sodium to then re-enter the tubular cell carrying amino acids and glucose

Question 11

How does passive diffusion work in the PCT?

Answer 11

Water follows the movement of ions glucose etc via osmotic diffusion

Question 12

What limb of the loop of henle is impermeable to water?

Answer 12

The ascending limb

Question 13

How do ions get moved out of the ascending loop of henle?

Answer 13

Na+ gets pumped into the interstitium, then Cl- follows down the electrochemical gradient

creates a hypertonic environment in the interstitial fluid

Question 14

What does the DCT and collecting duct control

Answer 14

excretion of water and electrolytes

Question 15

What area is the site of K+ excretion and NaCl absorption?

Answer 15

DCT and collecting duct

Question 16

What substance is completely reabsorbed in the PCT?

Answer 16

Glucose

It is co-transported with sodium

Question 17

When would glucose be excreted in the urine?

Answer 17

When the plasma load exceeds the reabsorptive capacity called the renal threshold

Question 18

What percentage of filtered urea is exreted?

Answer 18

around 40%

Question 19

What is the effecr of ADH on the kidney tubules?

Answer 19

It increases water reabsorption in the DCT and collecting duct

Question 20

What part of the adrenal gland produces aldosterone?

Answer 20

It is produced and secreted in the zona glomerulosa

in response to the RAAS system

Question 21

What is the effect of aldosterone on kidney tubules?

Answer 21

It activates transcription and synthesis of new Na+ channels, new K+ channels and new Na+/ K+ pumps

Question 22

What is ANP released in response to and what is its effect?

Answer 22

It is released in response to increased atrial stretch
and it increases excretion of Na+ to decrease blood pressure

Question 23

What produces BNP and what it is in response to?

Answer 23

It is produced by CNS neurones in response to higher BP and blood volume

Question 24

Where is urodilatin produced and what is it produced in response to?

Answer 24

It is produced in distal tubular epithelial cells and it dilates the afferent arteriole to increase GFR

Question 25

What is the function of PTH?

Answer 25

It enhances the apical Ca2+ function

mediated by cAMP

Question 25

What is the function of PTH?

Answer 25

It enhances the apical Ca2+ function

mediated by cAMP

Question 26

What is the by-product of protein metabolism in birds?

Answer 26

Uric acid

Question 27

What is the name of the glands in birds that do the majority of Cl- and Na+ excretion

Answer 27

Salt glands

Question 28

What is secondary active transport?

Answer 28

When they follow the electrochemical gradient of the cell

Question 29

What occurs in the ascending loop of henle?

Answer 29

Sodium is actively pumped out, Cl- then follows via the electrochemical gradient

Question 30

Where can all the aquaporins be found?

Answer 30

1 in the PCT
2 in the apical membrane of the DCT
3, 4 in the basolateral membrane of the DCT/ collecting duct