Renal Anatomy 2: The Nephron

Question 1

This is the microscopic functional unit of the kidney and is responsible for urine formation.

Answer 1

Nephron

Question 2

What are the 2 types of nephrons?

Answer 2

Cortical and juxtamedullary nephrons

Question 3

These nephrons make up most of the nephrons and lie mainly in the cortex.

Answer 3

Cortical nephrons

Question 4

These nephrons extend deep into the medulla. It is important for the formation of concentrated urine.

Answer 4

Juxtamedullary nephrons

Question 5

Each nephron is comprised of what 3 structures?

Answer 5

Glomerular capsule, renal tubules (PCT and DCT) and collecting duct

Question 6

Each nephron is associated with what 2 structures?

Answer 6

Glomerulus and peritubular capillaries

Question 7

These are specialised for filtration. It is fed and drained by arterioles. Blood pressure is also tightly regulated here.

Answer 7

Glomerular capillaries

Question 8

These are specialised for absorption and reabsorption. It receives filtered blood from the glomerular capillaries (via efferent arterioles) and reabsorbed filtrate from the nephron.

Answer 8

Peritubular capillaries

Question 9

These are extensions that follow the nephron loops deep into the medulla. Thee are only found in juxtamedullary nephrons.

Answer 9

Vasa recta

Question 10

This is the term for when a glomerulus is enclosed by a glomerular capsule. It is the site of filtration barrier.

Answer 10

Renal corpuscle

Question 11

Where is the site of the filtration barrier?

Answer 11

Renal corpuscle - where nephron and capillary meet

Question 12

This is the first part of a nephron and is responsible for receiving filtrate.

Answer 12

Capsular space

Question 13

What are the 2 layers of epithelia in the glomerular capsule?

Answer 13

Inner visceral layer of podocytes

Outer parietal layer of simple squamous epithelium

Question 14

This is the specific place in the glomerular capsule that receives the filtrate.

Answer 14

Capsular space

Question 15

These are specialised epithelia that surround the glomerular capillaries.

Additional question:
Its branches form intertwining foot processes known as _________.

Answer 15

Podocytes; pedicels

Question 16

These form in between pedicels and is where filtered blood passes through into the capsular space.

Answer 16

Filtration slits

Question 17

This lies between the blood and capsular space. It allows free passage of water and small molecules, but restricts passage of most proteins.

Answer 17

Filtration barrier/blood-urine barrier

Question 18

True or false. RBCs are filtered into the nephron.

Answer 18

False. They’re proteins - and too big to be filtered into the nephron.

Question 19

What are the 3 layers of the filtration barrier?

Answer 19

Fenestrated endothelium of glomerular capillary

Fused basement membrane

Filtration slits

Question 20

What kind of endothelium lines the glomerular capillary?

Answer 20

Fenestrated epithelium (simple squamous)

Question 21

This renal tube is responsible for the bulk reabsorption of substances from the nephron. It is surrounded by peritubular capillaries.

Answer 21

Proximal convoluted tube

Question 22

The proximal convoluted tube has what kind of epithelium?

Answer 22

Cuboidal epithelial cells, but leaky and has microvilli

Question 23

Why does proximal convoluted tube have a lot of mitochondria?

Answer 23

Because ATP is needed to carryout lots of reabsorption (active transport)

Question 24

What are the 3 main structures found in the proximal convoluted tube?

Answer 24

• cuboidal epithelium
• dense microvilli (brushborder enzymes)
• highly folded basolateral membrane (for high SA)

Question 25

This is surrounded by vasa recta and is responsible for dipping down into the medulla. (absorption and reabsorption of different substances is reflected by changes in epithelium)

Answer 25

Nephron loop

Question 26

This renal tube is responsible for fine tuning of reabsorption using hormones like aldosterone. It is made of cuboidal epithelium but has no brush border and has fewer mitochondria.

Answer 26

Distal convoluted tube

Question 27

This is where the filtrate from several DCTs drains into.

Answer 27

Collecting ducts

Question 28

What are the 2 cells found in the collecting duct? What are their functions?

Answer 28

Principal cells - reabsorption

Intercalated cells - acid/base balance

Question 29

The reabsorption at this structure is influenced by both aldosterone and ADH.

Answer 29

Collecting duct

Question 30

What kind of epithelium is in the distal convoluted tube?

Answer 30

Simple cuboidal epithelium

Question 31

In histology, how do you distinguish between the proximal convoluted tube and the distal convoluted tube?

Answer 31

PCT = has a fuzzy lumen (due to microvilli brush border)

DCT = has a clear lumen (because no microvilli)

Question 32

What type of epithelial cells would you find in the nephron loop?

Answer 32

• nephron loop is composed of PCT and DCT

PCT => simple cuboidal epithelia with microvilli brush border & lots of mitochondria
DCT => simple cuboidal with no microvilli brush border & no mitochondria
Ascending and descending limb of nephron loop => simple squamous epithelium