Structure and function of nephron

1. NEPHRON
Presented by-
Shruti Richa
Assistant professor
Central Institute of Pharmacy

2. Introduction
 “Nephron is the basic structural &
functional unit of kidney which helps
in formation of urine.
 The word nephron is derived from
the Greek word – nephros, meaning
kidney. There are about millions of
nephrons in each human kidney.

4. Types of Nephron
 There are two types of nephron on the
basis of location):
Cortical (found in cortex
region)
Nephron
Juxtamedullary (found in
medulla region)

5. 1. Cortical nephron:
 These are the nephrons present within the
cortex. These are short and is about 80% of
the total nephrons.
 Here, vasa recta is not present.
2. Juxtamedullary nephron:
 These extend into the medulla. These are about
20%.
 Here, vasa recta is present.
Note: The vasa recta, the capillary networks
that supply blood to the medulla. Vasa means
vessels & recta means erect or straight. Means
straight blood vessels or blood veseels that go
straight with renal medulla.

6. Anatomical Divisions of
Nephrons
Nephron
Renal Corpuscle Renal Tubule
Glomerules PCT
Bowman’s Capsule Loop of Henle
Descending
Ascending
DCT

7. Anatomy of Nephron
 It is a long tube-like structure, its length varies
from 35–55 mm long.
 The structure of nephron comprises two major
portions:
A. Renal Corpuscle
B. Renal Tubule
 At one end, the tube is closed, folded and expanded,
into a cuplike structure called the Bowman’s capsule
or renal corpuscular capsule, which has cluster of
blood vessels called the glomerulus.
 This capsule and glomerulus together constitute the
renal corpuscle.
Renal corpuscle = Bowman’s capsule + Glomerules

9. Renal Corpuscle
 It consist of glomerulus surrounded by a Bowman’s
capsule.
 The glomerulus arises from an afferent arteriole
and empties into an efferent arteriole.
 The Bowman’s capsule is made up of simple sqamous
epithelial cells & divided into three layers:
A. Outer (Parietal layer): It is made up of epithelial
cells with minute pores of diameter 12nm.
B. Middle (Basement membrane): It is made up of
fibrils etc. This layer is selectively permeable.
C. Inner (Visceral Layer:) It consists of large cells
called podocytes which bear finger-like projections
called podocel. Podocytes are covering of
glomerules It contains filtration slits which
prevents the filtration of medium sized proteins.

11. Renal Tubule
 The renal tubule is a long and convoluted structure
that emerges from the glomerulus and can be
divided into three parts based on function:
A. The proximal convoluted tubule (PCT) due to its
proximity to the glomerulus; it stays in the
renal cortex.
B. loop of Henle, or nephritic loop because it
forms a loop (with descending and ascending
limbs) that goes through the renal medulla.
C. The third part of the renal tubule is called the
distal convoluted tubule (DCT) and this part is
also restricted to the renal cortex.
 Bowman’s capsule extends to form highly coiled
tubules called PCT. PCT continues to form the loop
of Henle which ascends to DCT, which in turn opens
into the collecting duct.

12. Proximal Convoluted Tubule
(PCT)
 The blood brought by the renal artery is filtered
by the glomerulus and then passed to the PCT.
 Maximum reabsorption takes place in PCT of the
nephron.
 PCT is the region of renal tubule where
reabsorption of essential substances like glucose,
proteins, amino acids, a major portion of
electrolytes and water takes place.
 It is made up of simple cuboidal epithelium in
them. It selectively secretes ions such as
hydrogen, ammonia, and potassium into the
filtrate and absorbs HCO3
–from it. Thus, PCT
maintains the electrolyte and acid-base balance of

13. Henle’s Loop
 Henle’s loop has a descending and an
ascending limb.
 Both the descending and ascending limbs
show different permeability. The
descending limb is permeable to water but
impermeable to an electrolyte, while the
ascending limb is permeable to
electrolytes but impermeable to water.
Since the electrolytes get reabsorbed at
the ascending loop of Henle, the filtrate
gets diluted as it moves towards the

14. Distal Convoluted Tubule (DCT)
 The DCT, which is the last part of the
nephron, connects and empties its contents
into collecting ducts that line the medullary
pyramids. The collecting ducts amass contents
from multiple nephrons and fuse together as
they enter the papillae of the renal medulla.
 Similar to PCT, DCT also secretes ions such as
hydrogen, potassium, and NH3 into the
filtrate while reabsorbing the HCO3
–from the
filtrate. Conditional reabsorption of sodium
ions and water takes place in DCT. Thus, it
maintains the pH and sodium-potassium level
in the blood cells.

15. Collecting Duct
 It is also called as duct of Bellini.
 Collecting duct is a long, straight tube
where H+ and K+ ions are secreted to
maintain the electrolyte balance of the
blood. This is also the region where the
maximum reabsorption of water takes
place to produce concentrated urine.

16. Functions of Nephron
 It convertes blood into the
urine, reabsorption, secretion, and
excretion of numerous substances.
 To remove all waste products including the
solid wastes, and other excess water from
the blood,
 As the blood passes through the glomerulus
with high pressure, the small molecules are
moved into the glomerular capsules
and travel through a series of tubules.
 The cell present in each tube absorbs
different molecules excluding the glucose,
water, and other beneficial molecules

17. REFERENCES
 https://byjus.com/biology/nephron-function-renal-tubules/

19. Activity Time
 Label the structures of nephron with the help of given
hints:
Max. Time: 3 min.

20. Question Time
1. ____________ and _____________
are known as the renal corpuscle.
A. Bowman's Capsule and Renal Cortex
B. Glomerulus and Bowman's Capsule
C. Loop of Henle and Renal Medulla
D. Proximal Convoluted Duct and Distal
Convoluted Duct

21. 2. Which part of the Loop of Henle is
ONLY permeable to water?
A. Descending Limb
B. Transverse Limb
C. Ascending Limb

22. 3. Which part of the renal tubule
performs the “final touches” on the
filtrate before it leaves the kidney as
urine?
A. Collecting Tubule/Duct
B. Renal Papilla
C. Loop of Henle
D. Distal Convoluted Tubule

23. 4. Which parts of the nephron are found
in the renal medulla of the kidney?
A. Proximal Convoluted Tubule and Distal
Convoluted Tubule
B. Loop of Henle and Distal Convoluted
Tubule
C. Loop of Henle and Collecting Tubule
D. Loop of Henle (except the descending
limb) and Distal Convoluted Tubule

24. 5. Blood flows out of the glomerulus via
the:
A. Afferent arteriole
B. Capillaries
C. Vasa Recta
D. Efferent arteriole