ANATOMY - Nephron

Question 1

What is the nephron?

Answer 1

The nephron is the microscopic functional unit of the kidney

Question 2

What are the two main functional components of the nephron?

Answer 2

Renal corpuscle
Renal tubule

Question 3

(T/F) The number of nephrons varies between breeds

Answer 3

FALSE. The number of nephrons does not differ between breeds however the size of the renal corpuscles does vary

Question 4

What is the cortical labyrinth?

Answer 4

The cortical labyrinth is the arrangement of the renal corpuscles and coiled proximal convoluted tubules (PCT) and coiled distal convoluted tubules (DCT)

Question 5

What are medullary rays?

Answer 5

Medullary rays are the arrangement of straight proximal convoluted tubules (PCT) and straight distal convoluted tubules (DCT) and origins of the collecting ducts

Question 6

What are renal corpuscles?

Answer 6

The renal corpuscles are the blood-filtering components of the nephron consisting of the glomerulus and Bowman’s capsule

Question 7

What is Bowman’s capsule?

Answer 7

Bowman’s capsule is the blind ending origin of the nephron surrounding the glomerulus

Question 8

Describe the two poles of Bowman’s capsule

Answer 8

Vascular pole: the afferent and efferent arterioles enter and exit the glomerulus
Urinary pole: the proximal convoluted tubule (PCT) arises

Question 9

What are the two layers of Bowman’s capsule?

Answer 9

Parietal layer
Visceral layer

Question 10

What is the name of the space between the parietal and visceral layer of Bowman’s capsule?

Answer 10

Urinary space

Question 11

What is the function of the urinary space?

Answer 11

The urinary space is where filtrate is collected before passing into the proximal convoluted tubule (PCT)

Question 12

Which layer of Bowman’s capsule is in direct contact with the glomerulus?

Answer 12

The visceral layer of Bowman’s capsule is in direct contact with the glomerulus

Question 13

What are the components of glomerular filtration barrier?

Answer 13

Fenestrated glomerular endothelium
Glomerular basement membrane
Podocytes of the visceral layer of Bowman’s capsule

Question 14

What is the function of the glomerular filtration barrier?

Answer 14

The glomerular filtration barrier acts to filter components of the blood based on particle size and charge to produce a filtrate

Question 15

Histologically, what type of cells are the glomerular endothelial cells?

Answer 15

Fenestrated, simple squamous endothelial cells

Question 16

What is the glomerular basement membrane?

Answer 16

The glomerular basement membrane is the modified, combined basement membrane of the podocyte cells and the glomerular endothelial cells

Question 17

What is the function of the mesangial cells?

Answer 17

The mesangial cells produce a matrix which permeates the glomerular basement membrane to phagocytose any debris retained during filtration

Question 18

What are pedicels?

Answer 18

Pedicels are extensions of the podocyte cells which are directly in contact with the glomerular basement membrane

Question 19

What is the name and function of the spaces between the pedicles of the podocytes?

Answer 19

The spaces between the pedicels are known as filtration slits which are covered by a thin membrane known as the slit diaphragm. These filtration slits are where blood components are filtered

Question 20

Describe the histological appearance of the proximal convoluted tubules (PCTs)

Answer 20

Simple cuboidal epithelium, microvillous brush border, indistinct cell boundaries, basal nuclei

Question 21

What are the three specialised structures of the proximal convoluted tubule (PCT) epithelium which allows for reabsorption?

Answer 21

Microvilli
Leaky junctions
Cell wall interdigitations

Question 22

What are the methods of reabsorption by the proximal convoluted tubules (PCTs)?

Answer 22

1. Paracellular reabsorption
2. Passive or active trans-cellular reabsorption

Question 23

What is the function of the counter current multiplier system in the medulla?

Answer 23

The counter current multiplier system creates the concentration gradient in the medulla required to concentrate the urine

Question 24

Which structures make up the counter current multiplier system in the medulla?

Answer 24

The loop of Henle and the Vasa recta

Question 25

Which structures make up the juxtaglomerular apparatus?

Answer 25

Macula densa
Extraglomerular mesangial cells
Juxtaglomerular cells

Question 26

What is the function of the juxtaglomerular cells?

Answer 26

The juxtaglomerular cells synthesise and secrete renin

Question 27

What is the function of the macula densa?

Answer 27

The macula densa regulates blood pressure through the renin-angiotensin-aldosterone mechanism

Question 28

Where are the macula densa cells located in the nephron?

Answer 28

The macula densa cells are located at the vascular pole of the glomerulus within the distal convoluted tubule (DCT)

Question 29

Describe the histological appearance of the distal convoluted tubules (DCTs)

Answer 29

Simple cuboidal epithelium, distinct cell boundaries

Question 30

Describe the histological appearance of the collecting ducts/papillary ducts

Answer 30

The collecting ducts/papillary ducts are pale staining with a simple cuboidal/columnar epithelium with distinct cell boundaries

Question 31

What are the papillary ducts?

Answer 31

The papillary ducts are the most distal region of the collecting duct system where the collecting ducts have fused

Question 32

Where do the papillary ducts terminate in the unilobar kidney?

Answer 32

The papillary ducts terminate at the renal crest of the unilobar kidney

Question 33

What type of epithelium lines the renal pelvis?

Answer 33

Transitional epithelium/urothelium