Structure of Nephron
Each kidney has nearly one million Nephrons.
Nephron is the Structural and Functional unit of kidney.
It is an epithelial tube which is about 3 cm long and 20-60 mm in
diameter.
Structure of Nephron
Proximal convoluted Distal convoluted
tubule tubule
Efferent
Afferent arteriole
arteriole
Glomerulus
Collecting
Bowman’s duct
capsule
Descending limb
of loop of Henle Ascending limb
of loop of Henle
Glomerulus is a network or tuft of capillaries present within the
Bowman's capsule.
It is formed by the afferent arteriole (branch of Renal artery).
Blood from the glomerulus is carried away by an efferent
arteriole.
Glomerulus
Bowman’s
capsule
At the proximal or closed end the nephron is expanded and
curved inwardly to form a double walled cup shaped Bowman's
capsule.
Bowman’s
capsule
The outer wall of Bowmans capsule is composed of flattened
squamous cells.
Podocytes Flattened squamous
cells
The inner, invaginated wall that lines the concavity of Bowmans
capsule is composed of a special type of cells called Podocytes.
Podocytes
Filtration slits
or slit pores
Podocytes are arranged in an intricate manner so as to leave
some minute spaces called filtration slits or slit pores.
Malpighian body (Renal corpuscle)
Glomerulus + Bowman's capsule = Malpighian body or Renal
corpuscle.
It is responsible for first step of urine formation (Filtration).
Efferent
Afferent arteriole
arteriole
Malpighian Glomerulus
body or
Renal Bowman’s
corpuscle capsule
Proximal Convoluted Tubule (PCT)
The epithelial cells of this region are specialized for transport of
salts and other substances from the lumen to the interstitial
fluid.
Proximal Convoluted
Tubule (PCT)
Simple cuboidal brush
border epithelium
Numerous microvilli
Increase the Surface Area
So Maximum reabsorption
Maintain the pH and
ionic balance
LOOP OF HENLE
Hair pin loop like structure.
Descending limb Ascending limb
of loop of Henle of loop of Henle
Descending Limb
Thick descending limb of loop of Henle
Simple cuboidal epithelium.
Permeable to water
but
Impermeable to salts
Thin descending limb of loop of Henle
Simple squamous epithelium.
Ascending Limb
Thick ascending limb of loop of Henle
Simple cuboidal epithelium.
Permeable to salts
but
Impermeable to water
Thin ascending limb of loop of Henle
Simple squamous epithelium.
Distal Convoluted Tubule (DCT)
Ascending limb of Henle's loop
merges into distal convoluted tubule .
Lined by Simple Cuboidal Epithelium.
Conditional reabsorption of Na+ &
water takes place in this segment.
Maintain pH and ionic balance.
The DCT of different nephrons open into
a straight tube called collecting duct.
Collecting Duct
Lined by Cuboidal Epithelium.
Allows passage of small amounts of
urea into the medullary interstitial to
keep up the osmolarity.
Concentration of urine.
he Malpighian corpuscle, PCT and DCT of the nephron are
situated in the cortical region of the kidney, whereas the loop of
Henle dips into the medulla.
Malpighian PCT DCT
Cortex
corpuscle
Loop
of
Henle Medulla
TYPES OF NEPHRON
AND
JUXTAGLOMERULAR
APPARATUS
According to their position,
nephrons are of two types
Cortical Juxta Medullary
Nephron Nephron
Juxta Medullary Nephron
Cortical Nephrons
Juxtamedullary
Cortical nephrons
nephrons
Constitute about 85% of Constitute about 15% of
total (75 - 85%). total (15 - 25%).
Malpighian corpuscles are
Malpighian corpuscles are
located at the junction of
close to kidney surface.
cortex and medulla.
Here LOH mostly confined LOH of these nephrons is
in cortex and a very small long, dipping deep down in
part of it runs in medulla. medulla.
Juxtamedullary
Cortical nephrons
nephrons
Peritubular capillary Peritubular capillary network
network present. is not well developed.
Vasa recta is absent or Vasa recta present.
highly reduced.
