The Nephron- structural and functional considerations

Question 1

list the components of the nephron

Answer 1

Renal corpuscles
PCT and DCT
Peritubular capillary network
Interstitium
Loops of henle
vasa recta
collecting ducts /papillary ducts

diagram on anki

Question 2

filtration takes place in what structures in the nephron

Answer 2

bowmans capsule and glomerulus

Question 3

the renal corpuscle is made up of what structures wihtin nephron

Answer 3

glomerulus + bowmans capsule

Question 4

number of nephrons found in kidney varies between…

Answer 4

species

Question 5

approx how many nephrons are found in the;
elephant
man
dog
cat
mouse

Answer 5

Elephant: approx.. 7 million per kidney
Man: approx.. 1 million per kidney
Dog : approx.. 0.5 million per kidney (adult 12 kg dog).
Cat: approx.. 200,000 per kidney (adult)
Mouse: approx..11,000 per kidney

Question 6

do additional nephrons develop once kideny is fully deveoped?

Answer 6

no

Question 7

name the functional roles of the nephron

Answer 7

Filtration
Reabsorption
Setting up concentration gradient
Secretion
Collecting duct- concentration of urine

Question 8

function of parts of nephron is refelcted in… and influeced by what substances?

Answer 8

Function is reflected in histological structure

Function varies under influence of Aldosterone and ADH

Question 9

which strcutures are found in the cortex region and which in the medulla region

Answer 9

on anki

Question 10

where are the medullary rays located

Answer 10

in the cortex

Question 11

what are the medullary rays comprised of

Answer 11

comprised of arrangemnts of renal corpuscles (central area) which are surrounded by straigh parts of proximal distal tubules and collecting tubules

Question 12

function of the renal corpuscle

Answer 12

filtration barrier

Question 13

type of epithelium in PCT and bowmans capsule

Answer 13

pct= simple cuboidal
bowmans= simple squamous

Question 14

describe the formation of the renal corpuscle

Answer 14

glomerulus makes contact with bowmans capsule
glomerulus starts pushing inwards till the renal corpuscle is formed

diagram on anki

Question 15

renal corpuscle terms;
-what is the term which describes the region where the glomerulus and bowmans capsule make contact?
-term describing outer surface layer of balloon formed
-term describing space between both other layers

Answer 15

-visceral layer
-parietal layer
-urinary space

Question 16

term given to filtrate which ultimately forms the urin in the renal corpuscle
2 types of poles in renal corpuscle

Answer 16

urinary pole
Urinary & Vascular poles

Question 17

what are the mesangial cells
-function

Answer 17

cells that sit in the convulutuions of other structures within renal corpuscle.
-produce a supporting matrix and togetehr with globelular basement membrane; phagocytose any debris retained by filtration barrier -like a hoover!

Question 18

FILTRATION occuring in renal corpuscle resultsin…

Answer 18

removal of nitrogenous wastes (plus lots of good stuff too)

Question 19

filtration is based on…

Answer 19

particle size and charge (-vely charged particles are repelled)

Question 20

desrcibe what structures the filtrate passes into in renal corpuscle.
blood exits through…

Answer 20

passes into the urinary space and then on into the PCT (proximal convuluted tubule)
-through glomerulus via efferent arteriole

Question 21

function of proximal convoluted tubule

Answer 21

reabsorption of around 70% of glomerular filtrate

Question 22

what can be seen on a histological section when looking at PCT )proximal convoluted tubule)

what does PCT consist of

PCT forms part of the…

Answer 22

Abrupt change in epithelium at the ‘urinary pole ‘ of bowman’s capsule (simple squamous to cuboidal epithelium with ‘brush border’)
Microvilli can be seen

The proximal tubule consists of a convoluted part and a straight part

cortical labyrinth

Question 23

what structures does the PCT contain within that allow for reabsorption to occur

Answer 23

microvilli, leaky intercellular junctions, inter-digitations in cell wall

Question 24

2 types of cellular pathways that occur within PCT

Answer 24

trans-cellular pathways- passive and active

Question 25

features of PCT in a H&E section

Answer 25

Basal nuclei (towards base of cell), microvillus (brush) border- pink-fluffy border, lack of cell boundaries.

Question 26

name the structures found in a histological section of the medulla which make up the counter current multiplier system

Answer 26

1. thin descending loop of henle (from PST)
2. thin ascending loop (to DST)
3. descending vasa recta (efferent arterioles)
4. ascending vesa recta (similar to venules)
5. Collecting duct- concentration of urine

Question 27

what is the function of the juxtaglomerular cells

Answer 27

production of renin (also known as an angiotensinogenase)
juxtaglomerular cells store renin until they are told to release it

Question 28

name the 3 cells found in the juxtaglomerular apparatus

Answer 28

juxtaglomerular cells

macula densa cells

Mesangial cells (Lacis cells)

Question 29

function of the macula densa cells

Answer 29

Sense sodium chloride concentration in the lumen and stimulate the juxtaglomerular cells to synthesize and release renin into the bloodstream
-blood pressure regulation

Question 30

function of the distal convoluted tubule (DCT)

Answer 30

-Re-absorption sodium, chloride, calcium and magnesium (actively)
-Tubular Secretion (H+, K+(aldosterone))

Question 31

mai nhistological differences between DCT and PCT

Answer 31

-PCT has that fluffy brush border which is thr microvilli, DCT does not have this
-fewer DCT in number compared to PCT
-DCT have more lumen in the middle in general
-DCT much paler and more columnar than PCT

Question 32

collecting ducts in kidney fuse to form what

Answer 32

large papillary ducts