Functional Histology of the Urinary Tract Flashcards
What is the kidney surrounded by?
A fibrous capsule
What is the kidney organised into?
Two layers, the cortex and the medulla
What does the cortex contain?
The renal corpuscles
What does the medulla contain?
Tubules
Where is the renal blood supply from?
The renal artery
What is the renal artery a branch of?
The abdominal aorta
What does the renal artery eventually become?
The glomeruli and the vasa recta
What are the vasa recta?
The ‘straight vessels’ that run up and down the medulla
Label this diagram

- A - Superficial glomeruli
- B - Interlobular vein
- C - Peritubular capillary bed
- D - Arcuate vein
- E - Arcuate artery
- F - Ascending vasa recta
- G - Descending vasa recta
- H - Henle’s loop of nephron
- I - Interlobar vein
- J - Interlobar artery
- K - Renal medulla (pyramid)
- L - Duct of Bellini
Label this diagram

- A - Convoluted tubules
- B - Cortex
- C - Bowman’s capsule
- D - Glomerulus
- E - Renal corpuscle
- F - Medullary rays
- G - Loops of Henle and collecting tubules
- H - Medulla
What does the kidney nephron consist of?
- Renal corpuscle
- Proximal Convoluted Tubule
- Loop of Henle
- Distal Convoluted Tubule
What is the function of the renal corpuscle?
It is the blood filtering component of the nephron
What does the renal corpuscle consist of?
- Vascular pole
- Urinary pole
Draw a labelled diagram of the kidney nephron

What does the vascular pole of the renal corpuscle consist of?
- Afferent/efferent arterioles
- Glomerulus
What does the urinary pole of the renal corpuscle consist of?
Bowman’s capsule
What is the renal tubule derived from in development?
The ureteric bud
What happens to the renal tubule during development?
It envelops the growing glomerulus, resulting in a double-layered cover
What is the double layered cover of the renal tubule called?
The Bowman’s capsule
Label this histograph
- A - Bowman’s Capsule + Glomerulus
- B - PCT x-section

Label this histograph
- A - Bowman’s space
- B - Bowman’s capsule
- C - Glomerulus

What is the filtration barrier in the kidney made up of?
- The capillary endothelium
- The visceral layer of Bowman’s capsule
What is the visceral layer of the Bowman’s capsule made up of?
Podocytes
What are podocytes?
‘Cells with feet’
What do podocytes look like?
Lots of tentacles wrapped around the capillaries
What kind of capillary endothelium does the filtration barrier have?
Fenestrated, the leakiest capillary in the body
What invests in the capillary endothelium of the filtration barrier?
Podocytes
What is made when the podocytes invest in the capillary endothelium
Filtration slits
What do the podocytes and fenestrated capillary endothelium of the filtration barrier share?
A basement membrane
What does the parietal layer of the Bowman’s capsule make?
A ‘funnel’
What is the purpose of the funnel created by the parietal layer of the Bowman’s capsule?
To collect the ultrafiltrate to drain into the PCT at the urinary pole
Label this diagram of the filtration barrier

- A - Secondary process (pedical)
- B - Filtration slit
- C - Podocyte
- D - Podocyte cell body
- E - Primary process
What is the proximal convoluted tubule?
The lonegest, most convuluted section of the tubule
What happens at the PCT?
Reabsorption begins
What is the PCT lined with?
Simple cuboidal epithelium with a pronounced brush border membrane
What does the loop of Henle consist of?
- Pars recta
- Thin descending limb
- Thin ascending limb
- Thick ascending limb
What are the parts of the loop of Henle described on the basis of?
Apperance/epithelial lining
What does each part of the loop of Henle have?
Specialised function
Where does the thin limb of the loop of Henle travel?
Dips down into the medulla
What in the thin limb of the loop of Henle lined with?
Simple squamous epithelium
Is there active transport in the thin limb of the loop of Henle?
No
Is there a brush border in the thin limb of the loop of Henle?
No
What does the thin limb of the loop of Henle histologically resemble?
A small capillary, but no RBCs
Where is the thick ascending limb of the loop of Henle best seen?
In the medulla
What is the thick ascending limb of the loop of Henle interspersed with?
- Thin limbs
- Vasa recta
- Collecting duct
What is the thick ascending limb of the loop of Henle lined with?
Simple cuboidal epithelium
What differentiates the thick ascending limb from the PCT?
The thick ascending limb doesn’t have a brush border
What takes place in the thick ascending limb?
Active transport
Where is the distal convoluted tubule found?
In the cortex
What does the DCT make contact with?
- Its ‘parent’ glomerulus
What does the distal convoluted tubule contain?
Numerous mitochondria
How does the DCT compare to the PCT?
It has no brush border and a larger lumen
What is this histogram showing?

PCT
What is this histogram showing?

Thin limb of Henle’s loop
What is this histograph showing?

Thick limb of Henle’s loop
What is this histograph showing?
Distal convoluted tubule

What are the structures of the juxtaglomerular appartus named for?
Their close proximity to the glomerulus of each nephron
What does the juxtaglomerular appartus consist of?
- Macula Densa
- Juxtaglomerular cells
- Extraglomerular Mesangial cells (aka lacis cells)
Label this histograph

- A - Distal convoluted tubule
- B - Macula densa
- C - Proximal convoluted tubule
- D - Extraglomerular mesangial cells
What is this histograph showing?

A collecting duct
What is the collecting duct?
A continuatin of the DCT via the collecting tubule
What is the collecting duct similar in apperance too?
The thick limbs of Henle’s loop
How does the apperance of the collecting duct differ from that of the thick limbs of Henle’s loop?
The lumen is larger, and tends to be more irregular than circular
What forms the renal pyramid?
Progressively larger ducts merge together and empty at the renal papilla. This forms a pyramid shape
Label this histograph

- A - Ducts
- B - Calyx
What is this histograph showing?

The ureter
What is the ureter?
A tube running from the renal pelvis to the bladder
How many layers of muscle does the ureter have?
Two, with a third appearing in the lower third
What is the ureter lined by?
A specialised epithelium, transitional (aka urinary) epithelium, or urothelium
How many layers or muscle does the urinary bladder have?
3
What type of epithelium is the internal epithelium of the urinary bladder?
Transitional
What is the urinary bladder surrounded by?
An outer adventita
What are the features of urothelium?
- Stratified epithelium
- ‘Umbrella cells’ on the surface layer
What is the purpose of the umbrella cells on the urothelium?
Make it impermeable