excretory system

1. THE WASTE DEPOSITING SYSTEM
EXCRETION PART 1

2. • Waste substances are generated as a result
of metabolic activities in our body
• Some organisms waste formed in one
activity will be utilized in other. Ex: Plants
• But most organisms expel the waste
substances out the body. Ex: Human being

3. EXCRETION IN HUMAN
• Waste products are CO2 or water or
nitrogen compounds like Ammonia,
Urea, Uric acid, Bile pigments, excess of
salts, etc
• Most poisonous waste product is
Ammonia.
• Waste substances exist in blood which
carries them to human excretory system
for excretion

4. Excretory system
• A pair of kidneys
• A pair of ureters
• Urinary bladder

5. Excretory system
There are a pair of bean shaped,
reddish brown kidneys in dorsal
cavity attached to dorsal body
wall one on either side of the
back bone.

6. • The size of the kidney is 10 cm in
length ,5 to 6cm in breath 4 cm
in thickness .
• Each kidney is convex on outer
side and concave on inner side.
Excretory system

7. • The position of right kidney is little
lower than the left kidney due to the
presence of liver
• The inner side of each kidney has a
fissure / Hilus for the entry of renal
artery, exit of renal vein and also an
ureter
Excretory system

8. • Renal artery brings oxygenated
blood loaded with waste products.
• Renal vein carries deoxygenated
blood.
• The waste products which are
carried by the blood are filtered by
the kidneys.
Excretory system

9. • It shows two distinct regions.
• Cortex dark is coloured outer zone.
• Medulla is pale inner zone.
• Each kidney is made up of more than
1 million microscopic thin tubular
function units called as Nephrons /
Uriniferous tubules
L S OF KIDNEY

10. STRUCTURE OF NEPHRON
2 parts
Malpighian body
Renal tubule

11. Malpighian body
• It consists of a blind cup shaped border end of
nephron called as Bowman’s capsule
• And also a bunch of fine blood capillaries called
Glomerulus.
• Together called as Malpighian capsule/ Renal capsule.

12. • Glomerulus develops from afferent
arteriole and it gives to efferent.
• Diameter of afferent arteriole is more
than the efferent arteriole.
• This exerts a lot of pressure on
glomerulus that facilitates filtration.

13. • Bowman’s capsule is lined by a
single layer of squamous epithelial
cells called ‘Podocytes’.
• There are small pores between
podocytes to facilitate the
filtration.

14. Renal tubule
Proximal Convoluted Tubule
Distal Convoluted Tubule
Loop of Henley
Renal tubule is completely entangled with blood
capillaries formed from efferent arteriole which in
turn form renal venule and in turn form renal vein

15. Collecting tubule
• DCT opens into collecting tubule.
• Collecting tubules form pyramids
and calyces which in turn open
into Pelvis.

16. • A pair of whitish, narrow distinguishable
and muscular tubes of 30cm in length.
• Each ureter arises from Hilus of kidney.
• It moves downwards and obliquely open
into urinary bladder and carry urine
through the peristaltic movement.

17. • It is a median pear shaped sac.
• It stores urine brought by ureters.
• The storage capacity is 300 to 800 ml.

18. • It is a tube that takes urine from urinary
bladder to outside.
• It is guarded by a ring of muscles or
sphincter.
• 4 cm long in females and 20 cm long in
males and called as vestibule.
• It is common opening with reproductive
system in males.

19. Mechanism of Urine
formation
4 Phases
• Glomerular Filtration
• Tubular Reabsorption
• Tubular Secretion
• Formation of hypertonic urine

20. Check yourself
1. The right kidney is placed slightly lower than the left kidney due to the
presence of ____________.
2. Renal artery brings __________ blood whereas renal vein carries ______
blood.
3. The functional unit of kidney is ____________.
4. Bowman’s capsule is lined with a layer of epithelial cells called __________.
5. Glomerulus : Filtration : : PCT : _________
6. Tubular secretion takes place in _________.
7. The hormone that is responsible for maintaining osmotic concentration of
body fluids is ___________.
8. Abbreviation of PCT ___________
9. Abbreviation of DCT ___________
10.The most poisonous of all waste products of metabolism is __________.

21. ECRETION PART 2
THE WASTE DEPOSITING SYSTEM

22. MICTURITION
• Urine is temporarily stored in the bladder.
• Two circular sphincter muscles in the bladder.
• When the bladder is filling up both the
sphincters are constricted to close the urethra.
• When the pressure of urine increases the walls of
the bladder are stretched and this triggers off an
automatic reflex action which causes the upper
sphincter to relax.
• But lower sphincter is under control of the brain
and its a voluntary action.

23. MICTURITION
• Urge of micturition occurs when the
bladder is filled with 300 – 400 ml of
urine.
• But maximum capacity is 700 – 800 ml.
• This leads to voluntary micturition.
• 1.6 to 1.8 l of urine per day.
• May also increase by intake of water or
fluids.

24. COMPOSITION OF URINE
• Transparent fluid.
• Amber colour due to the presence of Urochrome.
• Protein rich diet results in more urea as well
carbohydrates results in sugar.
• More intake of water results in more volume of urine.

25. COMPOSITION OF URINE
• 96% of water
• 2.5 % of organic substances like urea, uric acid, creatin,
water soluble vitamins, hormones and oxalates, etc.)
• 1.5 % of inorganic solutes like sodium, chloride,
phosphates, sulphate, magnesium, calcium, iodine, etc.
• More intake of water results in more volume of urine.

26. KIDNEY FAILURE
• Complete and irreversible kidney failure - ESRD
• ESRD – End Stage Renal Disease – results in fill up of
water in the body - UREMIA
Solution ?
Reasons?

27. DIALYSIS (ARTIFICIAL KIDNEY)
• Filter the blood of a person when both kidneys are damaged.-
Haemodialysis.
3 to 6 hours

28. KIDNEY TRANSPLANTATION

30. SN ORGAN SUBSTANCES EXCRRETED
1 Liver Urochrome, steroid hormones, extra drug
vitamins and extra alkaline
2 Large
intestine
Excess of salts of calcium, magnesium and iron
along with feces
3 Lungs Carbon di oxide and water
4 Skin Sweat containing metabolic wastes and also the
sebum containing waxes, sterols, hydrocarbons
and fatty acids.
ACCESSARY EXCRETORY ORGANS

31. EXCRETION IN OTHER ORGANISMS
Organism/ phylum Excretory system
Protozoa Simple diffusion
Porifera &
Coelenterate
Water bath
Platyhelminthes Flame cells
Nematoda Renette cells

32. EXCRETION IN OTHER ORGANISMS
Organism/ phylum Excretory system
Annelids Nephridia
Arthropoda
Malpighian tubules/
green glands
Mollusca Meta nephridia
Echinodermata Water vascular system

33. EXCRETION IN PLANTS
• Plants breaks down waste substances at much
slower rate than in animals.
• Oxygen itself is considered as the waste product of
photosynthesis and sent out through the stomata.
• Plants can get rid of excess of water through the
transpiration/ guttation.
• The waste can also get rid of plants by bark, fruits,
etc.
• Stored in the fruits in the form of Raphides.

34. EXCRETION IN PLANTS
Primary metabolites: Carbohydrates, Proteins, Lipids.
Secondary metabolites: Alkaloids, Tannins, Resins, Gums & Latex.

35. EXCRETION IN PLANTS

36. EXCRETION IN PLANTS
Tannins: Tanning of leather and in medicines. Ex: Cassia,
Acacia
Resins: Gymnosperms – Varnishes.
Gums: Binding industry, Medicines and food. Ex: Neem.
Latex: Rubber from Hevia brazialensis, Bio diesel from Jatropa.

37. EXCRETION
SECRETION

38. Check yourself
1. Maximum capacity of urinary bladder is ___________.
2. 2. The Amber colour of the urine is due to the ____________.
3. Protein rich food in diet results in more ________ in the urine.
4. Abbreviate ESRD ______________________.
5. Filtering the blood of a person outside the body in a machine when both
kidneys are damaged is known as __________.
6. The blood is taken out from _____________ of the body and sent back
through __________ into the body in the process of dialysis.
7. First kidney transplantation was performed by ______________.
8. Choose the odd one out – (Rennet cells, Flame cells, Glial cells, Nephridia).
9. Renette cells : Platyhelminthes : : Flame cells : _____________
10.Carbohydrates : Primary metabolites : : Alkaloids : _______________.
11.Alkaloid which is used as antimalarial drug is ____________.