Histology

Question 1

What are the 3 main functions of the kidney

Answer 1

Maintain water and electrolyte homeostasis, body fluid osmolarity and acid-base balance

2. Excrete toxic metabolic waste products (mainly urea and creatinine)
3. Act as an endocrine gland, producing renin and erythropoietin

Question 2

What covers the kidney

Answer 2

A thin but strong capsule of dense collagen fibres

Question 3

What is the hilum

Answer 3

Site of entry of renal artery and exit of renal vein and ureter

Question 4

What is the medulla divided into

Answer 4

medullary pyramids with apices (papillae) pointing toward the hilum ending on minor calyces

Question 5

Where exactly does urine evolve from

Answer 5

The papillae

Question 6

What does the renal column do

Answer 6

Anchors the cortex to the medulla and provides a convenient way for the vasculature to reach the cortex

Question 7

What is the nephron composed of

Answer 7

renal corpuscle

renal tubules

Question 8

What is the renal corpuscle

Answer 8

a know of blood vessels surrounded by a capsule (Bowman’s)

Question 9

How many nephrons are found within each human kidney

Answer 9

600,000-1million nephrons

Question 10

What are podocytes

Answer 10

Specialised epithelium which lies on top of the glomerular capillaries

Question 11

What separates the blood from the glomerular filtrate

Answer 11

Capillary endothelium and podocytes

Question 12

What do the podocytes form

Answer 12

Filtration slits as the podocytes have interdigitating cell processes

Question 13

What is found between the podocytes and capillary epithelium

Answer 13

thicker than usual basal lamina made up of GAGs

Question 14

What produces the mesangium and what is it

Answer 14

Scattered mesangial cells produce

It is a connective tissue core

Question 15

What are the functions of the mesangial cells

Answer 15

Support

removal of debris

Question 16

What type of cells line the Bowman’s capsule

Answer 16

stratified squamous epithelium

Question 17

Describe the walls of the renal capillaries

Answer 17

Fenestrated walls

Question 18

What is the function of a Proximal convoluted tubule cell

Answer 18

Recapsures glucose, peptides, small proteins and many other items from the filtrate

Question 19

What lines the proximal convoluted tubules

Answer 19

Stratified squamous epithelium

Question 20

Describe the appearance of the Loop of Henle

Answer 20

Begins as a thin descending limb then changes direction like a hair pin and ascends before widening out and continue ascending

Question 21

What is the main role of the loop of Henle

Answer 21

It creates a high osmotic pressure in the extracellular space of the medulla with salts and urea but does not actually change the volume of within the tubule

Question 22

Describe the appearance of the thin limb of the loop of Henle

Answer 22

Thin, simple squamous lining in which the nuclei typically protrude into the lumen

Question 23

Describe the appearance of the thick limb of the loop of Henle

Answer 23

Simple cuboidal epithelial cells with abundant mitochondria

Question 24

What cells line the collecting ducts

Answer 24

Simple cuboidal

Question 25

What tubule is the metabolically busiest cell in the Loop of Henle

Answer 25

Thick ascending limb

Question 26

What is the Vasa Recta

Answer 26

Loops of blood vessels that dip down into the medulla from above and then climb back up to the cortex

Question 27

Where are the distal convoluted tubules located

Answer 27

In the cortex

Question 28

What lines the distal convoluted tubules

Answer 28

simple cuboidal epithelium

Question 29

How are the structures of the proximal and distal convoluted tubules different

Answer 29

Distal lacks a brush border of extensive microvilli | Therefore they have a relatively smooth surface in comparison

Question 30

What are the medullary rays

Answer 30

Parallel arrays of tubules that head towards the medulla from the cortex

Question 31

What drugs are the collecting ducts responsive to | What do the drugs do

Answer 31

antidiuretics | They can change the osmolarity of the filtrate passing through

Question 32

What are the ducts of Bellini

Answer 32

Large excretory duct

Question 33

What is the Juxtaglomerular Apparatus

Answer 33

The feedback unit for the nephron to allow the nephron to know what is going on and what is has produced

Question 34

What 3 components is the Juxtaglomerular Apparatus made up of

Answer 34

``` Macula densa (sensory) Juxtaglomerular cells (mostly afferent) Extraglomerular mesangial cells ```

Question 35

Describe the path of the distal convoluted tubule

Answer 35

It goes back towards its own renal corpuscle that forms part of its very own nephron

Question 36

Where is the macula densa located and describe the appearance

Answer 36

on the side of the distal convoluted tubule nearest the afferent arteriole. The cells are taller, crowded together and the nuclei are intensely stained

Question 37

What is the function of the macula densa

Answer 37

Sensing ion composition in the DCT

Question 38

What do the juxtaglomerular cells contain/ secrete

Answer 38

Renin

Question 39

What type of cells are the juxtaglomerular cells

Answer 39

modified smooth muscle cells in wall of the afferent arteriole

Question 40

Describe how urine moves from where it is produced to where it is released from the body

Answer 40

Produced in the renal papilla Collected into the minor calyx flows through major calyx, renal pelvis, ureter and then the bladder Exits the body via the urethra on voiding

Question 41

What are almost all of the conducting parts of the urinary tract lined by

Answer 41

a special epithelium called transitional epithelium or urothelium It is stratified and found in 3-6 layers

Question 42

What are the cells on the luminal surface called and why

Answer 42

umbrella cells | they are domed

Question 43

Why does the epithelium have a special structure

Answer 43

the variability in thickness of cells represents different states of distension The apical surface o the cells at the surface have a thickened membrane to provide a highly impermeable barrier

Question 44

What lies below the epithelium in the the conducting parts of the renal system

Answer 44

Lamina propria and 2-3 layers of smooth muscle

Question 45

Describe the flexibility of the umbrella cells

Answer 45

They can change their appearance at the apical membrane - they can form invaginations in the tough membrane to help products come into the cell. They increase or decrease surface area as required

Question 46

Describe the histological differences between the proximal ureter and the distal ureter

Answer 46

A lot more smooth muscle distally compared to proximally | Less lamina propria (connective tissue in the distal ureter

Question 47

What are the female urethras line with

Answer 47

transitional epithelium which trasition to stratified squamous near its termination

Question 48

What is the male urethra lined with

Answer 48

Transitional epithelium. Membranous urethra extends from the prostate to the bulb of the penis - here transitional epithelium changed to stratified columnar cells What is the penile urethra line with

Question 49

What is the penile urethra line with

Answer 49

stratified columnar epithelium which near the tip of the penis becomes stratified squamous

Question 50

What is the prostate gland lined with

Answer 50

simple columnar secretory epithelium with a fibromuscular stroma