Histology

Question 1

How does the kidney act as an endocrine gland?

Answer 1

Produces:

 - Renin
 - Erythropoietin

Question 2

What is the kidney covered by?

Answer 2

Thin, strong, collagen capsule

Question 3

What is the medulla divided into and what direction do they point in?

Answer 3

Pyramids:

- Apices point to hilum (papillae)

Question 4

What is each nephron composed of?

Answer 4

Renal corpuscle

Renal tubules

Question 5

What is the approximate length of each nephron?

Answer 5

45-65mm

Question 6

What is the renal corpuscle formed from?

Answer 6

Glomerulus

Bowman’s capsule

Question 7

What epithelium makes up the Bowman’s capsule?

Answer 7

Simple squamous

Question 8

How many cell layers separate the blood and glomerular filtrate? What are these layers?

Answer 8

Two:

 - Capillary endothelium
 - Specialised epithelium on top of capillaries:
 - Podocytes

Question 9

What do the podocytes form?

Answer 9

Filtration slits (~25nm wide)

Question 10

What lies between the cell layers separating the blood and glomerular filtrate?

Answer 10

Thicker basal lamina (0.3μm instead of 0.05μm):

- Made of Glycosaminoglycan (GAGs)

Question 11

What forms the mesangium and what does it do?

Answer 11

Mesangial cells
Functions as connective tissue core:
- Support
- Removes debris

Question 12

Where does the Loop of Henle lie?

Answer 12

In the renal medulla

Question 13

What is the structure of the cells lining the thin descending limb of the Loop of Henle?

Answer 13

Simple squamous

Nuclei protrude into lumen

Question 14

What is the structure of the cells lining the thick ascending limb of the Loop of Henle?

Answer 14

Simple cuboidal

Abundant mitochondria

Question 15

Where is the distal convoluted tubule found?

Answer 15

Cortex

Question 16

What lines the distal convoluted tubule?

Answer 16

Simple cuboidal epithelium

Question 17

What does the DCT lack that the PCT has?

Answer 17

A brush border

Question 18

Where do the collecting ducts run alongside?

Answer 18

Straight segments of PCT and DCT in cortex

Question 19

Coupled with the structures collecting ducts run alongside, what is the name for these bundles?

Answer 19

Medullary rays:

- Parallel bundles

Question 20

What direction do the medullary rays run?

Answer 20

Perpendicular to kidney surface

Question 21

In the medulla, what do the collecting ducts run alongside?

Answer 21

Loops of Henle

Question 22

What epithelium lines the collecting ducts?

Answer 22

Simple columnar

Question 23

Where do the juxtaglomerula apparatuses form?

Answer 23

At site where DCT passes:

- Adjacent to vascular pole of same renal corpuscle

Question 24

What are the three components of the juxtaglomerular apparatus?

Answer 24

Macula densa
Juxtaglomerular cells
Extraglomerular mesangial cells/Lacis cells

Question 25

Where does the macula densa lie?

Answer 25

On side of DCT closest to afferent arteriole

Question 26

What are the features of the DCT cells?

Answer 26

Taller Crowded Intensely stained nuclei

Question 27

What do macula densa do?

Answer 27

Sense DCT ion composition

Question 28

What are the juxtaglomerular cells and what do they do?

Answer 28

Modified smooth muscle in afferent arteriole wall | Contain and secrete renin

Question 29

What are the extraglomerular mesangial cells?

Answer 29

Modified mesangial cells that extend out of the corpuscle

Question 30

What type of the epithelium is the urothelium?

Answer 30

Transitional stratified epithelium (3-6 cells)

Question 31

What are the cells at the luminal surface of the urothelium?

Answer 31

``` Umbrella cells (domed): - Special thickened and inflexible membrane ```

Question 32

Why does the urothelium have a special structure?

Answer 32

Variable thickness: - Different states of distension Apical surface of cells have a thickened membrane: - Impermeable

Question 33

What lies below the urothelium and what is it?

Answer 33

Lamina propria: | - 2-3 layers of smooth muscle

Question 34

How long is the urethra in women?

Answer 34

3-5cm

Question 35

What epithelium is the female urethra?

Answer 35

Transitional and then stratified squamous

Question 36

How long is the urethra in men?

Answer 36

~20cm

Question 37

How long is the prostatic urethra and what lines it?

Answer 37

3-4cm | Transitional epithelium

Question 38

How long is the membranous urethra, where does it like and what lines it?

Answer 38

~1cm: - From prostate to bulb of penis Transitional -> Stratified columnar epithelium

Question 39

How long is the penile urethra and what lines it?

Answer 39

``` ~15cm Stratified columnar (stratified squamous at tip of penis) ```

Question 40

What glands form the prostate gland?

Answer 40

Tubulo-alveolar

Question 41

What type of epithelium are the tubules in the prostate gland lined with?

Answer 41

Simple columnar secretory epithelium with fibromuscular stroma

Question 42

What fraction of seminal fluid volume is made up of prostate gland secretions?

Answer 42

~1/2