osmoregulation in invertebrates- it is a processes by which any organisms maintains the fluid and salt balance of its body, which is important for proper functioning of organs .

1. ZOOLOGY
PRESENTATION
GDC COLLEGE
REWA

2. IN
INVERTEBRATES

3. SYNOPSI
S
 1).INTRODUCTION.
 2). DEFINITION.
 3).CLASSIFICATION OF MEDIUM ON THE BASIS OF
OSMOLARITY.
 4).CLASSIFICATION OF ANIMALS ON THE BASIS OF THEIR
ABILITY TO REGULATE OSMOTIC CONCENTRAT
 5).OSMOREGULATION IN INVERTEBRATES.
I. PROTOZOA.
II. PORIFERA.
III. COELENTERATA.
IV. PLATYHELMINTHES (FLATWORMS).
V. NEMATODA (ROUNDWORMS).
VI. ANNELIDA.
VII. ARTHOPODA.
VIII. MOLLUSCA.
IX. ECHINODERMATA.
6). CONCLUSION

4. 1).INTRODUCTION-
 Most animals get water that is present in the food
only, others drink it too, and is also formed during
respiration.
 Water is essential for life, its loss called
DEHYDRATION.
 However, the excess of water may dilute body fluid,
and causes BLOOD PRESSURE and OEDEMA.
 Excess of water is a waste product and it is excreted
in sweat, urine and feaces.
 Regulation of water and salt balance of the body is
called OSMOREGULATION.
 Therefore,osmoregulation is an essential process to
regulate the cellular metabolic activities.

5. 2).DEFINITION-
 It is a process that regulate the body’s salt and water
content.
 It maintains the composition of body fluids at a steady
state for efficient metabolism in the cells.
 Body fluids are of two types-1).Intracellular fluid.
2).Extracellular fluid.
 Intracellular fluid- fluid found within the cells.
for example; cytoplasm.
• Extracellular fluid- fluid found outside the cells
for example; blood,
lymph.
• Osmoregulation involves water movement which
follows solute by

6. •OSMOSIS- It is a type of diffusion where the movement of
water occurs from a dilute solution (hypotonic) to a strong
solution (hypertonic) across a semi-permeable membrane.
• OSMOLARITY- It is the total solute concentration expressed as
moles of solute per liter of solution.
• Its unit of measurement is milli osmol per liter (mosmolLˉ¹).
• Osmolarity of fresh water is generally less then 50mosmolLˉ¹.
• 3).CLASSIFICATION OF MEDIUM ON THE BASIS OF
OSMOLARITY- There are three types of
mediums-
1) . ISOTONIC MEDIUM- A solution having concentration equal
to that of the living cell is called isotonic medium.
• RBC’S placed in a isotonic medium neither swell up nor shrunk
in shape.
• HYPOTONIC MEDIUM – A solution having LOW concentration
than that of a living cell is called hypotonic medium.

7. • RBC’S placed in hypotonic medium gets swell up in shape.
3). HYPERTONIC MEDIUM- A solution having concentration
higher then that of
a living cell is called hypertonic medium.
•RBC’S placed in a hypertonic medium gets shrunk in shape.
• figure showing RBC’S in different concentration
mediums.

8. ABILITY TO REGULATE THEIR OSMOTIC
CONCENTRATION-
 1).OSMOREGULATION IN AQUATIC ANIMALS-
There are four types of animals-1).Poikiloosmotic animals.
3).Osmoconformers
2).Homoiosmotic animals. 4).Osmoregulators.
 Poikiloosmotic animals- Animals in which internal osmotic
concentration varies according to its external environment are
called poikiloosmotic animals. for example; lower invertebrates,
many annelids. It includes-
a) Stenohaline Animals- Aquatic animals which tolerate
only a narrow range of salinities and are bound to constant
salt content environment are called stenohaline.
2).Homoiosmotic Animals- Animals which maintain a constant
osmotic concentration of body fluid in changing external
salinity are called homoiosmotic animals.
a).Euryhaline animals- Animals that can tolerate a wider range of osmotic
concentration or tolerant to verities of salinities are euryhaline.ex-

9. OSMOCONFORMERS AND OSMORRGULATORS-
3). Osmoconformers - Animals in which the
concentration of body fluid changes according to
their external environment are osmotically
labile(dependent), are belong to the category of
osmoconformers. for example- all aquatic
invertebrates.
4).Osmoregulators- Animals which are able to
maintain their internal osmotic environment
constant are osmotically stable(independent) are
belong to the category of osmoregulators. For
example- all vertebrates, except; myxine.

10. 6).OSMOREGULATION IN INVERTEBRATES-
I. Osmoregulation in protozoan's-
 Osmoregulation in Amoeba-
 Osmoragulatory Organ- Contractile vacuole.
 Mechanism for osmoregulation-
 The protoplasm of amoeba proteus is of higher
concentration then the freshwater of its environment.
 Due to the difference in concentration between the
protoplasm and outer environment, water is actively
secreted in to the contractile vacuoles by endo-osmosis
through the vacuolar membrane.
 Tiny membrane bound water filled feeder vacuoles also
get incorporated in to the contractile vacuole filling it with
water.
 As water, continues to fill the vacuoles it increases in size.

11. ectoplasm zone where the ectoplasmic pressure results in
contraction and bursting.
• Due to the force of contraction, the content of vacuoles that is, water,
CO2,ammonia
Are discharged to the outside.
 Contractile vacuole • mechanism of
osmoregulation
 Osmoregulation in paramoecium-
 Osmoregulatory Organ-Two contractile vacuoles.(anterior and
posterior).
 Mechanism for osmoregulation-

12. • This extra amount of water is got rid off by contractile vacuole.
• The contractile vacuole contract(systole) and expand(diastole) at
regular intervals
Assisted by contractility of myofibrils.
• •Now the water from cytoplasm is secreted in to some of the tubules of
endoplasmic reticulum.
• From endoplasmic reticulum it flows down the nephridial tubules in to the
feeder canals to accumulate in latters ampulla.
• This ampulla converge and discharge in to contractile vacuole.
 Osmoregulation in paramecium.

13. • when vacuole has grown to maximum size it contract and
discharged through an excretory pore.
•The marine and parasitic protozoan’s don’t face this problem
as their environment is isotonic to their cell contents. Therefore,
they lack contractile vacuoles.
II).OSMOREGULATION IN PORIFERA-
•The main excretory mater is ammonia.
•It leaves the cell by diffusion in to the
water filling the canals and surrounding
the sponge.
•From canal the waste matter is carried
out by outgoing water current.
•Most sponges are marine, with no
problem of surplus water in their cells.
•Few sponges live in hypotonic fresh
water, for ex- spongilla, have contractile
vacuole in most of their cells.
•This contractile vacuole functions in Water movement in

14. III).OSMOREGULATION IN COELENTERATA-
•They also get rid off waste matter by simple diffusion
through the cells.
•The waste matter entering the coelenteron leaves
when its water is renewed.
•Most of the coelenterons too are marine.
•Marine ones, don't have osmoregulatory
Problems.
•A few inhabit hypotonic fresh water.
•How fresh water coelenterates regulate
•The water content of cells is not clear, as
There are no contractile vacuoles found
In them.
WATER MOVEMENT IN
HYDRA.

15.  Osmoregulatory organ- Flame cells.
 Like the contractile vacuole ,The chief role of flame
cells is to perform osmoregulation.
 Mechanism of osmoregulation-
 They have flame cells with the bundles of vibratile cilia
for excretion. For example-planaria, flukes and
tapeworm.
 Flame cells receive the solutes and water from the
surrounding tissue fluid by ultrafiltration.
 Then they discharged the solutes and water into the
nephridial ducts.
 In the nephridial ducts the useful materials are
reabsorbed from it and some waste substances are
secreted in to it.

16. • The urine which is formed finally, is eliminated to the exterior
by excretory pore.
• In aquatic worms, the excretory product is ammonia.
 But, in parasitic worms, the
excretory product is fatty
acid.
 The fresh water flatworms
have more flame cells then
the marine ones.
 On the left hand side, there
is a diagram- Showing the
structure of a flame cell in
fasciola hepatica, teania
solium etc.

17. V.OSMOREGULATION IN NEMATODA(Roundworms)-
1). Osmoregulation in Ascaris-
• Osmoregulatory organ- They have a system of
intracellular canals and
 Cannaliculi opening out at the exterior pore.
 It has a H-shaped excretory system formed
of two intracellular longitudnal excretory
Canals interconnected by a transverse netwo
-rk of canaliculi.
This system plays a great role in water regula-
- tion, then in excretion.
• Nitrogenous waste (ammonium ions) are
• Mainly lost by diffusion across the body-
• Wall.

18. VI. OSMOREGULATION IN ANNELIDA-
OSMOREGULATORY ORGAN- They have many coiled tubular
stuctures called metanephridia for osmoregulation and excretion.
•STRUCTURE OF METANEPHRIDIA- It typically consist of
cilliated nephridial canal.
•This canal opens in to coelom by nephrostome.
•This canal opens outside or In to he gut by nephridiopore.
•MECHANISM OF OSMOREGULATION-
•Nephridia have rich blood supply,solute extract and water from
blood by ultrafiltraton.
•The nephridia then discharge this filtrate in to the nephridial
canal.
•In nephridial canal the useful material are reabsorbed from it, and
some waste substances are secreted in to it.
•The final urine so formed is passed in to the gut or to the exterior
by nephridiopore.
•Fluid expelled at the body surface consist of water, ammonia in
the aquatic from and urea in land form and salt which have not

19. • Excretion through the gut is adaption for water conservation.
• in the gut, water is absorbed in the blood.
• This metanephridia bring about excretion and water and ion regulation in
body.
 Types of nephridia in different classes of annelida-
 Class 1- polychaeta(nereis)-
 Type of nephridia- All nephridia opens out by a
nephridiopore and thus are ectonephric.
 Class 2-oligochaeta(earthworm)-
 Types of nephridium-
 In earthworm, nephridia are micronephric.
 In earthworm, depending upon their position the
Nephridia are of three types-
1. Septal nephridia.
2. Integumentary nephridia.
3. Pharyngeal nephridia.

20. 1 ). Septal nephridia- These nephridia are attached on septa.
• These are enteronephric as these open into the gut.
•2).Integumentary Nephridium-These
nephridia are attached on the inner side
of integument(skin).
• Like septal nephridia these are also
enteronephric.
3). Pharyngeal Nephridia- These are
present in three pairs of groups
of nephridia.
• Location- one pair in each of 4th,5th
and 6th body segment.
• unlike septal and integumentary
nephridia, these are ectonephric.
• Annelid nephridia bring about excretion
as well as water and ion regulation.
• In earth worms, excretory fluid keep the

21. 3). Class-Hirudinaria(leech))-
• Osmoregulatory organ- 17 pairs of small coiled
tubes,nephridia.
•Location- one pair in each segment from 6th to 22nd .
•Types of nephridia- there are two types of nephridia.
1). Testicular Nephridia. 2). Pre-testicular
Nephridia.
1).Testicular nephridia-
Location- posterior 11 pairs of nephridia,lying one
pair in each segment from 12th to 22nd are termed as
testicular nephridia.
•Due to the presence of a pair of testis sacs in each
of these segments, these nephridia are named as
testicular nephridia.

22. •It consist of 6 parts-
1. Main lobe.
2. Vesicles and vesicle duct.
3. Apical lobe.
4. Inner lobe.
5. Initial lobe, and
6. Ciliated organ.
2. Pre- testicular Nephridia-
•Location- 1st 6 pairs of nephridia are termed as pre-
testicular.
• since, these are located in segments 6th to 11, without
testis sacs themselves but in front of those containing
testis sacs, therefore they are termed as pre-testicular
lobe.
•they resemble to the testicular nephridia in all respects,
except that their initial lobe end loosely in general
connective tissue on their side of ventral nerve cord.

23. • Types of osmoregulatory organs in different classes
of arthopoda-
1). Class 1-Insecta(cockroach)-
• Osmoregulatory organ - Malphigian tubules.
• Location- float freely in the haemocoel.
• In cockroach,very fine,unbranched,yellowish,
Blind malphigian tubules are present.
• These tubules open in to the alimentary canal at
• The junction of midgut and hindgut.
• Each tubule is lined by cuboidal epithelium of
• Glandular cells.
• Malphigian tubules are capable of peristalsis to
• Move the waste matter though them.
• Structure and function of malphigian tubules-
• it has two regions, distal and proximal parts.

24. • its distal part secretes inorganic ions, uric acid, by active
transportation and
Water by the diffusion from haemolymph.
• This region is alkaline, from here, extracted matter moves in
solution called
•Primary urine, towards ileum.
•Now, in its proximal part,CO2 passes from haemolymph into
its lumen.
•This makes the content acidic, and this in turn makes the uric
acid to precipitate.
•Water, ions and useful materials are reabsorbed, changing
the primary urine
•Into final urine. By the gentle tubule contractions,the
precipitate is carried out into the gut.
•More reabsorption takes place in the hind gut.
• almost solid uric acid is finally eliminated with feaces.
•Excretion through the gut is an adaptation to conserve water.

25. 2).Class-Crustacea(Prawn)-
Osmoregulatory organ- They have a
pair of antennary or green glands and a
median renal sac for osmoregulation
and excretion.
Location- lie at the base of antenna and
opens out.
•It is formed of an end sac, a labyrinth
and a bladder.
•These draw the water having
dissolved substances from the
haemolymph in to their end sac by
ultrafiltration.
•Most salts are absorbed while
remaining flows into bladder.
•Excretory fluid comes here via lateral
ducts from the renal sac that lies over
stomach.

26. 3).Class-Arachnida(scorpion and
Spider)-
• Osmoregulatory Organ-They have
malphigian tubule or coxal glands,or
both for excretion.
•Spiders excrete guanine and are
said to be guanotelic.
VII.Osmoregulation in
Mollusca(unio)-
•Osmoregulatory organ- One or two
pair of kidney for excretion and
osmoregulation.
•Mechanism of osmoregulation-
•The kidneys open in to the
pericardium(coelom) at one end by
renopericardial
aperture(nephrostome).
•At the other end it opens into the

27. •In kidney, the primary urine is modified to final urine by
selective reabsorption and secretion.
•Final urine is passed into the mantle cavity via the
nepridiopore.
•In aquatic form waste matter is ammonia.
•In land form it is uric acid.
VIII. OSMOREGULATION IN ECHINODERMATA(STAR
FISH)-
•Osmoregulatory organ- They lack special excretory and
osmoregulatory organs.
•The nitrogenous waste materials,cheifly ammonia are lost by
diffusion through the thin walls of gills(dermal branches) and
tube feet(podia).
7). CONCLUSION- From the above description, it is clear
that there is a very crucial relationship of water and salt
concentration between an organism and its external
environment, by which it maintains the homeostasis of the

28. THANKYO
U
SUBMITTED BY- ANKITA
RICHHARIYA.
MSC 1ST SEM .
(ZOOLOGY).