Renal Histology

Question 1

What are the kidneys main functions? (4)

Answer 1

filter blood; regulate water, acid and salt balance; regulate blood pressure; produce hormones/enzymes eg renin.

Question 2

What are the basic functional sections of a nephron?

Answer 2

Filtration: Renal corpuscle
Reabsorption: Proximal tubules
Water extraction: think and thck ascending limbs
Salt fine tuning: Distal convoluted and connecting tubules.
Water reabs: collecting ducts

Question 3

What are parts of the renal corpuscle?

Answer 3

Vascular pole
Capillary tuft (glomerulus)
Visceral epi: podocytes
Parietal epi: squamous
Urinary space (Bowmans capsule as a whole)
urinary pole

Question 4

What is part of the filtration barrier?

Answer 4

Fenestrated endolthelial cells (covered in glycocalyx)
glomerular/capillary basement membrane
podocytes (with foot processes) to form slit membrane

Is a physical and charge selective barrier.

Question 5

What is the function of the glycocalyx?

Answer 5

Covered in negative charges, to repel plasma proteins

Question 6

Basement membrane

Answer 6

Thick
Collagen and negative charged
dense inner core (physical barrier)
less dense outer cores (charged -vely) (sandwich)

Question 7

Podocytes

Answer 7

Primary and secondary processes interdigitate
slit membrane
covered in glycocalyx

Question 8

Mesangial cells

Answer 8

Smooth muscle cells
supportive/contractile role, to maintain shape
produce ECM
between afferent and efferent arterioles (core of tuft)
glomerular sclerosis

Question 9

Juxtaglomerular apparatus

Answer 9

Made of thick ascending limb
macula densa (part of TAL where adheres to renal corpuscle): sense salt conc
juxtaglomerular cells: modified SM cellsin afferent arteriole that secrete renin.

Question 10

PCT features

Answer 10

cuboidal epithelium
brush border of microvilli (for abs. and pinocytosis)
lateral processes and infoldings to increase surface area
reabsorbs 2/3 of filtrate

Question 11

Thin limb cells

Answer 11

thin squamous epithelium
water reabs.
nuclei bulge into lumen

Question 12

Distal tubule cells

Answer 12

fine salt tuning, pH and urine conc.
cuboidal epi.
interdigitating lateral processes
no brush border, short microvilli
no pinocytosis

Question 13

Collecting duct

Answer 13

cuboidal to columnar

Question 14

Kidney lobe structure

Answer 14

Renal corpuscles, PCT and DCT in renal cortex
Corpuscles can be deep or outer cortex
Medulla: collecting ducts and loops of Henle
Collecting ducts fuse to form large ducts that open into renal papillae
medullary rays

Question 15

What is a medullary ray? (lobule)

Answer 15

A group of PCTs and DCTs with corpuscles all draining into a group of collecting ducts in the centre. IN CORTEX

Question 16

Kidney blood supply

DIAGRAM pg 12

Answer 16

renal artery-interlobar arteries-arcuate artery- interlobular artery- afferent arterioles- glomeruli- efferent arterioles- peritubular capillaries or IF CLOSE TO MEDULLA, form arterial vasa recta

Question 17

The ureter and bladder

Answer 17

Transitional epithelium, folding permitted
mucous membrane (lubrication/protection)
supepithelial CT (elastic)
smooth muscle (IL, OC)
adventitia

Question 18

urethra

Answer 18

epi goes

transitional- stratified columnar- stratified squamous