ggfffffffffffffffffffffffdfsrewrrrrrrrrrrrrrrrrrrrrrrrrsdddddddddddddddddccccccccccccccccccerwwwwwwwwwwwwwwwwwww433333333333333333333333333fddddddddddddddddddddddreeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeew44444444444444444444444444444444dfgter6555555555555555555555555555555555555ghhhhhhhhhhhhhhhhhhhhhhhhsdddddddddddderwerwewghbghhh

1. EXCRETORY SYSTEM
By Swagata
Sarkar

2. What Is Excretion ? Excretory Organs
Urinary System Production of Urine
Table of contents
01 The process of removal of harmful
and unwanted nitrogenous waste
products which are derived from
the
organism’s own metabolism.
02
Blood Supply
and
3 Major Steps
03 04
Along with their functions
Various parts:
• Kidneys
• Ureters
• Urinary Bladder
• Urethra

3. Excretion
A large amount of waste materials are
produced by metabolic activities. Such
materials are carbon dioxide , nitrogenous
waste etc. These materials become harmful if
retained inside our body in higher
concentration. So, our body has to remove
these materials through excretion.
The terms excretion, secretion and defecation
are different from each other.
• Defecation: removal of undigested food.
• Excretion: removal of metabolic waste like
urea, ammonia etc.
• Secretion: production of useful substance
like hormones, enzymes etc. by metabolism.
01

4. Excretory Organs
• Kidneys
• Lungs
• Skin
• Liver
02

5. Excretory organ Excretory products
1.Kidney Urea, uric acid,
ammonia, creatinine
through urine.
2.Liver Bile pigment
3. Skin(sweat gland) Sodium chloride,
water and traces of
urea through sweat.
4.Lungs Carbon di oxide
Different excretory organs
along with their excretory
products:

6. Parts Of Urinary
System:
Various parts:
 Kidneys
 Ureters
 Urinary Bladder
 Urethra

7. Parts Of Urinary
System In Detail:
Ureter:
 2 in number.
 Shape: bean shaped.
 Color: reddish brown.
 Size: 10 cm long and 6 cm wide.
 Location: located on either side
of backbone and protected by
the last two ribs.
 2 in number.
 Location: Each ureter arises from
the notch [hilum] in the median
surface of each kidney and connects
with urinary bladder.
 Function: Ureter carries urine from
kidney to urinary bladder.
 The front end of ureter is expanded
into the kidney and is called pelvis.
 1 in number.
 Location: lower part of the abdomen.
 Function: It temporarily stores urine.
 1 in number.
 Function: it carries urine to
outside of the body from urinary
bladder.
Kidney:
Urinary bladder:
Urethra:

8. Location and function of sphincter
muscles-
[Bladder sphincter and urethral sphincter] The sphincter
muscle guards the opening of urinary bladder into the
urethra.
It relaxes during the removal of urine.
Internal structure of kidney:
A longitudinal section of kidney shows 2 parts
➢
• Outer dark cortex
• Inner light medulla-- contains ‘renal pyramids’. Tip of
renal pyramids are called ‘papilla’.
• Composed of large no. of nephrons/ uriniferous
tubule/ renal tubules.
• Total no. of nephrons in each kidney- 2 million.

9. composed of 2 parts:
It is highly convoluted (folded) and as it
is proximal/ nearer to Bowman’s
capsule, so it is called proximal
convoluted tubule.
It is highly convoluted and as it is far
away from Bowman’s capsule, so it is
called distal convoluted tubule.
Detailed Structure Of Nephron:
Malpighian capsule:
PCT/ Proximal
convoluted tubule:
DCT/ Distal
convoluted tubule:
middle ‘U’ shaped part. It receives urine and
pass it to the pelvis.
Loop of Henle: Collecting duct:
Bowman’s capsule: thin
walled cup like structure.
Glomerulus: a knot like mass of
capillaries within the concavity of
Bowman’s capsule.

10. Production of Urine
Blood Supply To The
Uriniferous Tubules
3 Major Steps:
 Ultrafiltration
 Reabsorption
 Tubular Secretion

11.  A pair of renal arteries enter respective kidneys
 Inside each kidney, renal artery is divided and re-divided to form very fine
branches called arterioles.
 The arteriole that carries impure and oxygenated towards Bowman’s
capsule, called afferent arteriole.
 The afferent arteriole is divided into very fine capillaries and form a knot
like mass called glomerulus within the Bowman’s capsule.
 The capillaries of glomerulus reunite to form efferent arteriole and exit
the Bowman’s capsule.
 The efferent arteriole which carries pure blood, is again divided to form
secondary capillary network around renal tubule.
 Capillaries of secondary capillary network rejoin to form veins which
carry pure and deoxygenated blood.
 These veins join to form renal vein in each kidney and then they exit the
kidney.
Blood supply to kidney tubules:

12. Tubular secretion:
The filtration occurs under tremendous
pressure is called ultrafiltration. This
pressure occurs due to the difference in the
diameter of afferent and efferent arteriole.
The diameter of glomerular capillaries is
much less than the diameter of afferent
arteriole. Also the diameter of outgoing
efferent arteriole is two times narrower
than afferent arteriole. As the diameter is
decreasing, the pressure inside the fluid is
increasing. Because of this pressure, the
liquid part of blood along with urea,
glucose, amino acids and salts pass into the
renal tubule. This liquid in renal tubule is
called primary urine/ glomerular filtrate.
Walls of DCT secretes
potassium and certain
drugs like penicillin.
 Reabsorption in PCT: most
water, glucose, sodium and
chloride ions.
 Reabsorption in loop of Henle:
water and sodium ion.
 Reabsorption in DCT: remaining
chlorides and some water.
 Tubular reabsorption is called
‘selective reabsorption’- The
reabsorption of water and other
components is only to the extent
that the normal concentration of
blood is not disturbed.
Ultrafiltration:
Reabsorption:
Mechanism of urine
formation:

13. CREDITS: This presentation template
was created by Slidesgo, including
icons by Flaticon, and infographics
& images by Freepik
Thank
you!