1. A nephron is the functional unit of the kidney that filters blood to remove waste and regulate fluid balance. 2. A nephron contains a renal corpuscle with glomerulus and Bowman's capsule, and a renal tubule including the proximal convoluted tubule, loop of Henle, distal convoluted tubule and collecting duct. 3. The nephron uses selective reabsorption and secretion to filter the blood, remove waste from the body, regulate electrolyte and acid-base balance, and control blood pressure and production of erythropoietin and renin.

1. NEPHRON
1. A nephron is a unit of structure
and function of a kidney.
2. A kidney contains about a
million nephron.
3. It is about 3 cm long and 20-30
nm in diameter.
4. Nephrons are of two types :
(a)-cortical
(b)juxtamedullary

2. Differences between
cortical &
juxtamedullary
CORTICAL
JUSTAMEDULLARY
 Form only 20%
nephrons
NEPHRONS
NEPHRONS
of total
 Form 80% of total
nephrons.
 Are small in size.
 Lie mainly in the
renal cortex.
 Henle’s loops are
very short and
extend only a
little into the
medulla.
nephrons.
 Are in large in
size.
 Have bowman’s
capsule in the
cortex .
 Henle’s loops
are very long
and extend

4. Nephrons  Renal corpuscle
• Bowman’s capsule
• Glomerulus
 Renal tubule
. Proximal convolutes tubule (P
• Loop of Henle
• Distal convoluted tubule
(DCT)

5. Nephron consists of
…………………….
1) Renal corpuscle – the head of the
nephron
(a)The
renal corpuscle is composed
of Bowman’s capsule and glomeruli
(b)Bowman’s capsule is the cover of the
corpuscle that
surrounds the glomerulus
(b)the glomerulus is the network of
capillaries found inside
the corpuscle
2) Renal tubule – the tubular
passageway of the nephron

6. Nephron structures and functions
 Glomerulus
• The glomerulus is
surrounded by
Bowman's
capsule
• It is a network
of capillaries
that performs
the first step of
filtering blood.
• operates as a
nonspecific filter
- removes both
useful and nonuseful material

7. Layers of glomerulusEndothelial cells
• The endothelial cells of the glomerulus
contain numerous pores
• These pores are relatively large, they
allow for the free filtration of fluid,
plasma solutes and protein
 Glomerular basement membrane
•
The GBM is a fusion of the endothelial cell and
podocyte basal laminas
Podocytes
• Podocytes line the other side of the
glomerular basement membrane and form
part of the lining of Bowman's space.
• Podocytes form a tight pedicels that
control the filtration of proteins from the

8.  A The endothelial cells
 B. Glomerular basement membrane
 C. Podocytes:

9. functions
 Bowman’s Capsule
• It is double walled
cup-shaped.
• A sac that encloses
glomerulus
• transfers filtrate
from the glomerulus
to the Proximal
Convoluted Tubule
(PCT)

10. Layers of
bowman’s capsule-
 Parietal layer -
A single layer of simple squamous
epithelium.
• Does not function in filtration.
•
 Bowman's space • Between the visceral and parietal
layers, into which the filtrate
enters after passing through the
filtration slits.
 Visceral layer -

11. 2. Bowman's capsule – parietal layer
3. Bowman's capsule – visceral layer
4. Bowman's space (urinary space)

12. Tubule (PCT)
Lower part of Bowman’s
capsule leads in to PCT.
It lies in the renal
cortex.
PCT is lined by cuboidal
epithelial having brush
borders with long
microvilli for increasing
absorptive area.
And resting on a
basement membrane.
 that reabsorbs most of
the useful substances of
the filtrate: sodium
(65%), water (65%),
bicarbonate (90%),
chloride (50%), glucose

14. functions
 The loop of Henle
• U-shaped tube that consists
of a descending limb and an
ascending limb.
• begins in the cortex, receiving
filtrate from the PCT,
extends into the medulla,
and then returns to the
cortex to empty into the
distal convoluted
tubule(DCT).
• Its primary role is to

15. Nephron structures and functio
 Descending Limb of the Loop of Henle
• A part of the counter current
multiplier
• fully permeable to water and
completely impermeable to solutes
(salt particles)
• receives filtrate from the PCT, allows
water to be absorbed and passes
“salty” filtrate to the next segment.
“Saves water and passes the salt”

16.  Ascending Limb of the loop of
Henle
• a part of the counter current
multiplier
• impermeable to water and
actively transports (reabsorbs)
salt (NaCl) to the interstitial
fluid of the pyramids in the
medulla.
“Saves salt and passes the water.”
• the passing filtrate becomes

17.  Descending limb has two parts,
 (a) Thick segment-
• Thick segment constitutes about four-fifth of
the descending limb.
• It lies both inside cortex and medulla.
• The cell lining it are cuboidal.

(b) Thin segment-
• Thin segment is narrow part of descending
limb.
• It lies in medulla and is lined by flat
epithelial cell.

18. (Descending limb-Thick
and Thin)

19. functions
 Distal Convoluted
Tubule (DCT)
• It is highly coiled
part of nephron
• Lies close to
Malphighian body.
• Variably active
portion of the
nephron
• receives dilute fluid
from the ascending

20. Nephron structures
and functions
 Collecting Duct
• variably active
portion of the
Nephron
• Lined by
specialized
cuboidal
epithelial with
very few
microvilli.
• Collecting duct is
not a part of
structure of
nephron.

21. Juxtaglomerular
It is a microscopic structure in
apparatus- regulates the
the kidney, which
function of each nephron
The juxtaglomerular apparatus
consists of:
(1) the juxtaglomerular
cells
(2) the macula densa
(3) the Lacis cells or
agranular cells

22. Function of the JC cells1-Release of Renin
Stimulus : Low blood
pressure
2-Release of Aldosterone
hormone
It stimulates the DCT to
reabsorb salt. of salt (NaCl)
3-Reabsorption

23. Function of the Macula Densa Cells
• It monitors the salt content of the blood.
• If concentration of salt is raised, the
macula densa cells inhibit the release of
renin from the JC cells.
Function of the extra
glomerular mesangial cells
• It secretes
erythropoietin
• Erythropoietin is a
glycoprotein
hormone which
controls

24.  Nephrons has the following function1-Nephron remove urea and uric acid
from the blood
2-Nephron regulate blood pressure.
3-Nephron also remove
pigments,drugs,poisons,excess
vitamins from the blood.
4-It regulates the amount of mineral
salts in the body.
5-Also regulate blood pH.