Histology Flashcards

1
Q

3 functions of kidney and urinary tract?

A

maintain water and electrolyte homeostasis, body fluid osmolality and acid-base balance
excrete toxic metabolic waste products (urea and creatinine)
acts as an endocrine gland producing renin and erythropoietin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is erythropoietin

A

related to RBC production and maintainance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are the papillae?

A

apices of medullary pyramids which point towards the hilum, ending on the minor calyces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

at what point does urine drip off from the kidney/

A

papillae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what are the renal columns?

A

acts as conduit for renal blood supply

give structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

blood supply to the kidneys?

A

arteries enter and travel up through renal columns to supply the renal capsule
the medulla receives its supply from the capsule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

basic functional unit of the kidney?

A

nephron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are nephrons composed of and how long are they?

A

renal corpuscle and renal tubules

each is around 45-65mm long

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

nephrons empty into what?

A

collecting system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what does the renal corpuscle do?

A

production and collection of glomerular filtrate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

structure of the renal corpuscle?

A

formed of a tuft of capillaries called the glomerulus and the cup of simple squamous epithelium at the blind end of the nephron which the capillaries invaginate into called bowmans capsule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how does the renal corpuscle develop?

A

tuft of capillarie envaginate into bowmans capsule (cup of squamous epithelium)
coating the capillaries in the epithelium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what 2 cell layers separate the blood from the glomerular filtrate?

A

capillary endothelium and a specialised epithelium which lies on top of the glomerular capillaries (made of podocytes)
the endothelium is fenestrated with pores and the podocytes have interdigiting cell processes forming filtration slits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

how much glomerular filtrate is produced per minute? how does this compare to urine production?

A

100-125ml/min

only 1ml/min of urine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

afferent vs efferent arteriole?

A

afferent is larger as some volume is lost from capillaries at bowmans capsule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

vascular vs urinary pole of glomerulus?

A

the beginning of the proximal renal tubule is opposite where the afferent and efferent arterioles enter and leave bowmans capsule
= vascular end and urinary pole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is the mesangium?

A

stalk like core of the renal corpuscle made of mesangial cells and their extracellular matrix

18
Q

what are podocytes?

A

cells which cover most of the capillary surface within the glomerulus

19
Q

structure of podocytes?

A

branch in large branches, then small brnaches, then small foot branches called pedicles which intertwine to form filtration slits for glomerular filtration

20
Q

filtrate from the capillaries must cross what 3 layers?

A

fenestrated endothelium of the capillary wall
thick basement membrane shared by endothelium and podocyte)
filtration slits between pedicles

21
Q

what does the proximal convoluted tubule do?

A

reabsorption of water, proteins, amino acids, carbohydrates and glucose

22
Q

what is resorbed in the proximal tubule?

A

70% of sodium (active transport) and water follows (diffusion)
almost all glucose and amino acids (by co-transport)

23
Q

why are tight junctions important in proximal tubule cells?

A

to prevent the nutrients which have been resorbed being released into the space between cells

24
Q

what lines proximal convoluted tubules?

A

cuboidal epithelium

25
Q

what lines the loop of henle?

A

cuboidal epithelium
changes to simple squamous as it dives into the medulla as it has to be thinner
becomes cuboidal again as it ascends out of the medulla

26
Q

what does the loop of henle do?

A

creates hyperosmotic environment in the medulla

27
Q

proximal vs distal tubule?

A
proximal = thicker and more fuzzy/wooly, many many microvilli
distal = more smooth, less microvilli
28
Q

what are the components of the loop of henle?

A

thick descending limb
thin descending limb which makes a hairpin turn and journeys back
thin ascending limb
thick ascending limb

29
Q

describe blood supply tot he medulla

A

loops of thin walled vessels that dip down into the medulla from above and then climb back up to the cortex
= collectively called the vasa recta

30
Q

why is the vasa recta needed?

A

as a normal blood supply through the medulla would carry all the salts etc from the hyperosmotic environment created by the loop of henle around the body, destroying the osmotic gradient in the body

31
Q

what does the distal convoluted tubule do?

A

acid-base and water balance (absorption of water, Na and bicarbonate, excretion of K and H ions)

32
Q

what regulates reabsorption of Na in the distal convoluted tubule?

A

aldosterone

33
Q

what are medullary rays?

A

parallel bundles of collecting ducts, straight portions of the proximal tubules and distal tubules
running perpendicular to the surface of the kidney
visible to the naked eye as stripes in the cortex that point towards the medulla

34
Q

what happens in the collecting ducts?

A

ADH from the posterior pituitary increases the permeability of the collecting duct to water
therefore permeability of the duct is high during passage through the medulla and because of the high salt content in the surrounding tissue, water passes out of the lumen and a concentrated urine results

35
Q

what structures open into the minor calyxes at the renal papillae?

A

collecting ducts

36
Q

all parts of the urinary tract are lined with what?

A

transitional epithelium (or urothelium)

  • stratified (3-6 layers)
  • very impermeable
  • contains umbrella cells at luminal surface
  • special thickened, flexible membrane facing lumen
37
Q

how does transitional epithelium change?

A

as the bladder fills the transitional epithelium thins and stretches out

38
Q

what sits below the transitional epithelium?

A
lamina propria of connective tissue
2-3 layers of smooth muscle
- inner longitudinal
- outer circular
- another longitudinal layer (only in the bladder)
39
Q

describe female urethra

A

3-5cm

initial lined with transitional epithelium with transitions to stratified squamous near its termination

40
Q

describe male prostatic urethra

A

3-4cm
extends from bladder and through prostate gland
lined by transitional epithelium

41
Q

describe membranous urethra in males

A

1cm
from prostate to bulb of penis
transitional changes to stratified columnar

42
Q

penile urethra?

A

15cm

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