L6: Kidney Function

Question 1

Function of the kidneys

Answer 1

Remove waste products from the blood & produce urine

Question 2

3 controls of body fluid compositions

Answer 2

1) Volume regulation
2) Osmoregulation
3) pH regulation

Question 3

Function of glomerulus

Answer 3

Filters plasma to produce glomerular filtrate

Question 4

Function of the loop of henle

Answer 4

Recovery of water & sodium chloride from urine

Question 5

Function of the Bowman’s Capsule

Answer 5

Filtration of blood from glomerular capillaries

Question 6

3 main areas of the kidney

Answer 6

1) Cortex
2) Medulla
3) Renal Pelvis

Question 7

How does blood enter the kidney?

Answer 7

Via renal artery

Question 8

How does blood exit the kidney?

Answer 8

Renal vein

Question 9

Efferent arteriole

Answer 9

Brings blood back from glomerulus to the rest of kidney

Question 10

Afferent arteriole

Answer 10

Brings blood into the glomerulus

Question 11

Role of renal corpusle

Answer 11

Blood filtering component of the nephron in the kidney

Question 12

Important features of the nephron

Answer 12

1) Renal Corpuscle
2) Proximal Tubule
3) Loop of Henle
4) Distal Convoluted Tubule
5) Collecting Duct System

Question 13

2 nephron types

Answer 13

1) Cortical
2) Juxtamedullary

Question 14

Features of the cortical nephron

Answer 14

1) Glomerulus in the outer 2/3 of cortex
2) Short loop of Henle

Question 15

Features of the juxtamedullary nephron

Answer 15

1) Glomerulus in the inner 1/3 cortex
2) Long loop of Henle
3) Produces concentrated urine

Question 16

Process of glomerular filtration

Answer 16

Movement of fluids & solutes from the glomerular capillaries into Bowman’s space

Question 17

Importance of glomerular filtration

Answer 17

1st step of making urine

Question 18

Process of tubular secretion

Answer 18

Kidneys secrete waste products from peritubular capillaries into the tubules

Question 19

Process of tubular reabsorption

Answer 19

Movement of materials from the filtrate in the tubule into peritubular capillaries

Question 20

How is the amount excreted in urine made up of?

Answer 20

Amount filtered + Amount secreted + Amount reabsorbed

Question 21

Define glomerular filtration rate (GFR)

Answer 21

Volume of fluid filtered from the glomeruli per min

Question 22

What does the glomerular filtration rate (GFR) depend a combination of ?

Answer 22

A combination of:
1) Net filtration pressure
2) Permeability characteristics
3) Surface area

Question 23

How is glomerular filtration rate (GFR) regulated?

Answer 23

By neural & hormonal input

Question 24

What are starling’s forces involved in filtration?

Answer 24

Physical forces that determine the movement of fluid between capillaries & tissue fluid

Question 25

2 major starling forces?

Answer 25

hydrostatic pressure & colloid osmotic pressure

Question 26

How does plasma flow across a capillary wall in terms of HYDROSTATIC PRESSURE?

Answer 26

HIGH TO LOW

Question 27

How does plasma flow across a capillary wall in terms of COLLOID OSMOTIC PRESSURE ?

Answer 27

LOW TO HIGH

Question 28

What is the result of GFR when afferent arterioles are dilated?

Answer 28

Increase

Question 29

What is the result of GFR when afferent arterioles are constricted?

Answer 29

Decrease

Question 30

What 3 things does the GFR depend on ?

Answer 30

1) Starling forces involved in filtration 2) Net filtration pressure & permeability characteristics of filtration interface 3) Surface area of filtration interface

Question 31

Why is the SA of filtration interface changeable?

Answer 31

Due to the presence of mesangial cells

Question 32

What does mesangial cells contain?

Answer 32

Smooth muscle actin

Question 33

What do mesangial cells receive innovation from?

Answer 33

Sympathetic nervous system

Question 34

Where does reabsorption occur?

Answer 34

PCT & proximal straight tubule

Question 34

What happens when there is an increase in sympathetic nervous system activity?

Answer 34

Actin contract & cause SA of filtration increase to reduce, leading to a decrease in GFR

Question 35

What is the tubular wall made up of ?

Answer 35

Single layer of epithelial cells

Question 36

What is the capillary wall made up of ?

Answer 36

Endothelial cells

Question 37

Where does the luminal membrane face ?

Answer 37

Filtrate

Question 38

Where does the basolateral membrane face ?

Answer 38

Peritubular Capillary

Question 39

What is the structure of the proximal tubule segment related to ?

Answer 39

Important role in reabsorption

Question 40

Name 3 proximal reabsorption of organic nutrients

Answer 40

1) Na+ - coupled co-transporter 2) Tubular max system 3) Specific Transporters

Question 41

Where does tubular secretion occur?

Answer 41

Proximal tubule

Question 42

What transporters do secretion involve?

Answer 42

Basolateral & luminal membrane transporters

Question 43

2 examples of organic acids (anions)

Answer 43

1) Endogenous molecules (e.g bile salts) 2) Exogenous molecules (e.g drugs)

Question 44

First step of organic anion secretion in the proximal tubule

Answer 44

Organic anion enters epithelial cell via organic anion counter transporters

Question 45

Second step of organic anion secretion in the proximal tubule

Answer 45

OA- enters tubule lumen via ATP-dependent primary active transporters

Question 46

Where are organic anion counter transporters expressed on?

Answer 46

Basolateral membrane

Question 47

Where are ATP- dependent primary active transporters expressed on?

Answer 47

Luminal membrane

Question 48

2 examples of organic bases (cations)

Answer 48

1) Endogenous molecule (e.g creatinine) 2) Exogenous molecule (e.g morphine)

Question 49

First step of organic cation secretion in the proximal tubule

Answer 49

Organic cations enter proximal tubule via facilitated diffusion transporters

Question 50

Second step of organic cation secretion in the proximal tubule

Answer 50

OC enter tubule lumen via counter-transporters

Question 51

Where are counter-transporters expressed on?

Answer 51

Luminal membrane

Question 52

Where are facilitated diffusion transporters expressed on?

Answer 52

Basolateral membrane

Question 53

Equation for flow

Answer 53

Flow = pressure difference / resistance