Renal Hist

Question 1

What projects out of the hilum of the kidney?

Answer 1

Ureter

Question 2

What are the two zones of the kidney?

Answer 2

Outer - Cortex

Inner - Medulla

Question 3

What is located at the border between the medulla and cortex?

Answer 3

The arcuate vessels (they form the boundary)

Question 4

How many nephrons are in each kidney?

Answer 4

Between 0.3 and 1.5 million

Question 5

What is located on the outside of the kidney?

Answer 5

Thin connective tissue capsule

Question 6

What is located in the cortex?

Answer 6

•  Blood vessels
•  Tubules
•  Renal corpuscles

Question 7

Where are the vessels located in the cortex?

Answer 7

They are jammed in between the tubules and the corpuscles. It is a highly vascularised structure

Question 8

Where are the renal corpuscles located?

Answer 8

All of them are in the cortex

Question 9

Where does part does the tubule follow?

Answer 9

The first part always runs in the cortex (it is usually quite a tortuous path) it then turns and runs into the medulla (loop of Henle) before turning and upwards and returning to the cortex and eventually connecting to the collecting duct

Question 10

What are the two types of nephrons?

Answer 10

1.  Juxta medullary

2.  Cortical

Question 11

What is distinctive about the juxta medullary corpuscle?

Answer 11

The renal corpuscle is very close to the boundary of the medulla
AND
The tubule goes the furthest down into the medulla

Question 12

Percentage juxta medullary vs Cortical?

Answer 12

15 vs 85

Question 13

What is distinctive about the cortical nephron?

Answer 13

More superficial renal corpuscle

Loop which descends only part way into the medulla

Question 14

How much connective tissue is found in the kidney?

Answer 14

Very little connective tissue

It is mainly just nephrons and blood vessels packed in together as tightly as possible

Question 15

What is a glomerulus?

Answer 15

It is a tuft of capillaries connected to an arteriole

It doesn’t penetrate into the lumen of the tubule but is rather wrapped up in it

Question 16

What are the cells of the outermost layer of the corpuscle called?

Answer 16

The parietal layer

Question 17

What are the cells of the punched in section of the corpscle called?

Answer 17

Podocytes

Question 18

What is Bowman’s space?

Answer 18

A space which is continuous with the lumen of the tubule and is wrapped around the capillaries

Question 19

What do mesangial cells do?

Answer 19

They are a little like connective tissue - they provide the mechanical tension which pulls the base of the tuft of capillaries together

Question 20

Where does the ultrafiltrate accumulate?

Answer 20

In Bowman’s space crosses the capillaries, across the podocytes and enters into Bowman’s space

Question 21

What is Bowman’s space continuous with?

Answer 21

The lumen of the tubule

Question 22

Where are the vascular and urinary poles of the corpuscle?

Answer 22

180 degrees away from each other

Question 23

What type of cells are the parietal cells of Bowman’s capsule?

Answer 23

Squamous cells

Question 24

What type of cells are the tubules composed of?

Answer 24

Cuboidal epithelium

Question 25

What do podocytes do?

Answer 25

``` They branch (a lot) Eventually they interdigitate (there are little cracks here) Much of the surface is covered by the arms and processes of the podocytes ```

Question 26

Where is the ultra-filtrate formed?

Answer 26

The cracks in the interdigitations of the filtrate | Glycocalyx and slit membranes

Question 27

What happens to the basal lamina of the podocytes and that of the capillary?

Answer 27

They fuse to form a thick basal lamina

Question 28

What is the biggest molecule that is able to cross the basal lamina?

Answer 28

Basal lamina traps molecules above 69kD

Question 29

What is in the slit membrane?

Answer 29

Tiny pores - only a few nm across, this also acts as a filter

Question 30

Describe the steps of movement from the capillary to Bowman's space?

Answer 30

Cross the fenestrations in capillary Cross the basal lamina (less than 69kD in size) Cross the slit membrane (3-5nm) Enter Bowman's space

Question 31

What type of epithelium is seen in the proximal tubule?

Answer 31

Cuboidal epithelium

Question 32

What is seen on the surface of the cuboidal epithelium?

Answer 32

Microvilli

Question 33

What is seen at the boundaries between cells

Answer 33

Complex interdigitating cell boundaries. | Presumably to prevent the ultrafiltrate from entering into the intracellular space

Question 34

What transporters are seen on the basal surface of the cells of the proximal tubule?

Answer 34

Na+K+ATPases (pumps)

Question 35

What effect do the Na+K+ATPases have on the movement of Na+, Cl- and Water out of the lumen?

Answer 35

Na+K+ATPases move sodium out of the cell making the concentration of Na+ low. Sodium thus moves by diffusion across the apex of the cell (down the concentration gradient) into the cytoplasm before it it pumped out. Their is now an electrotonic imbalance and chloride follows passively. The movement of Cl- and Na+ then drives water across the membrane as well

Question 36

What is a prominent feature of cells of the proximal tubule?

Answer 36

They have lots of mitochondria (i.e. they require a lot of energy to perform their function)

Question 37

What types of epithelial cells are seen in the loop of Henle?

Answer 37

Squamous cells

Question 38

What is the loop of Henle permeable to?

Answer 38

Permeable to urea and water

Question 39

Are the cells of the loop of Henle using any active processes to move water and urea?

Answer 39

No - it is all passive | Also the permeability changes in different regions of the loop

Question 40

What type of cells make up the distal tubules?

Answer 40

Cuboidal cells

Question 41

Are the cells of the distal tubule active?

Answer 41

Yes - lots of mitochondria (even more) | The concentration gradients are harder to deal with so even more energy is required to get work done

Question 42

Do the cells of the distal tubule have microvilli?

Answer 42

No

Question 43

What is recovered in the distal tubule?

Answer 43

Chloride and sodium | Impermeable to water and urea

Question 44

What are the distinctive features of the collecting duct?

Answer 44

Cuboidal cells | Very large lumen

Question 45

What is the function of the collecting duct normally?

Answer 45

It is merely a conducting tube | It is impermeable to water and urea

Question 46

What happens to the collecting duct when there is body wide dehydration?

Answer 46

Under the action of vasopressin the wall can become permeable to water

Question 47

Which nephrons can make urine more osmotically concentrated then the blood?

Answer 47

Only the juxtamedullary nephrons

Question 48

What dos the efferent arteriole form?

Answer 48

A network of fine capillaries called the vasa recta

Question 49

What is the role of the vasa recta?

Answer 49

They carry away all of the products which have been recovered from the tubule

Question 50

What is seen in cross section of the medulla?

Answer 50

Tubules everywhere and blood vessels • Thin and thick walled loops of Henle • Collecting ducts • Capillaries of vasa recta

Question 51

What is the role of the ureter?

Answer 51

Conducts urine from kidney to bladder

Question 52

What type of epithelium lines the UT after the kidney?

Answer 52

Transitional epithelium | It is stratified and the apical cells have a balloon like shape

Question 53

What is the role of the transitional epithelium?

Answer 53

It is designed to keep it well away from the rest of the body - it can be a dangerous substance if it comes into contact with the rest of the body

Question 54

What moves urine from the kidney to the bladder?

Answer 54

The ureter has a thick muscularis of smooth muscle which moves urine in peristaltic waves

Question 55

Does the kidney like backpressure?

Answer 55

Nah it hates it :) need thus need to move urine away and do so in peristaltic waves

Question 56

What lines the bladder?

Answer 56

Transitional epithelium

Question 57

What controls the bladder?

Answer 57

ANS Two modes: Filling mode Emptying mode

Question 58

What happens in the bladder in 'filling mode'?

Answer 58

Relax the smooth muscle Constrict the sphincter This minimises the pressure in the bladder as it fills

Question 59

What happens to the bladder in 'emptying mode'?

Answer 59

Smooth muscle contraction Sphincter relaxation Micturitional voiding

Question 60

Where does the urethra penetrate?

Answer 60

The pelvic floor, which acts as a sphincter

Question 61

What type of epithelium lines the urethra?

Answer 61

Initially transitional and then stratified squamous