Functional histology of the kidneys

Question 1

Which arm of the loop of henley is thick and which is thin?

Answer 1

Descending arm = thin
Ascending arm = thick (half thick/half thin)

Question 2

What are the three stages of filtration?

Answer 2

1. Fenestration
2. Basement membranes
3. Filtration slit membrane

Question 3

What is the function of the PCT?

Answer 3

Re absorption from ultrafiltrate

Question 4

What specialised epithelial cells coat the capillaries of the renal corpuscle?

Answer 4

Podocytes

Question 5

Structure/Function of afferent artiole

Answer 5

• High pressure
• Brings blood into glomerulus
• Wider (large diameter)

Question 6

Structure/Function of efferent artiole

Answer 6

-Low pressure
- Takes blood away from glomerulus
- Narrower (smaller diameter)

Question 7

3 methods of reabsorbtion from PCT?

Answer 7

• Active transport (small molecules)
• Pinocytosis (macromolecules, especially proteins, degreaed within lysosomes, amino acid recycled to blood
• Passive flux (small molecules with concentration gradient)

Question 8

PCT epithelial cell

Answer 8

-Microvilli (high SA)

• Pinocytotic vesicles (carry macromolecules to lysosomes)
• Many lysosomes (recycles macromolecules)
• Many mitochondria (to fuel active transport)

Question 9

Thin loop of henle epithelial cell

Answer 9

thin squamous epithelial
minimum of organelles

Question 10

Loop of henle (thin arm) function

Answer 10

Function: Re absorption from ultrafiltrate
Passive flux only (osmosis)

Question 11

Thick ascending loop of henle/DCT function

Answer 11

Func: blood homeostasis
Via regulated active transport

Question 12

DCT epithelial cell

Answer 12

Cuboidal epithelial- thicker than squamous to reduce passive flux + accomodate organelles.
Many mitochondria
Few microvilli

Question 13

Collecting duct/collecting tubule functions:

Answer 13

Transport of urine to ureter

Water homeostasis: passive reabsorption of water regulated through epithelial permeability

Question 14

What is the juxtaglomerular apparatus

Answer 14

Where the DCT loops back to meet arterioles of the same nephron

Question 15

What are the 3 cell types

Answer 15

• Juctaglomerular cells( contain renin)
• Lacis cell
• Macula densa

Question 16

Macula densa function

Answer 16

sense conc of Na+ in DCT
Then signals to Jucxtaglomerular cells

Question 17

Function of juxtaglomerular cells

Answer 17

Releases renin- lowers Na+ conc in DCT. Renin indirectly increases vascular tone and Na+ reabsorption

Question 18

Function of lacis cells?

Answer 18

UNKNOWN