venitrogenous

ia: are
the
nitroge fund
T h e s e of the
excretory

fluids.
:
r e m o v a l

ways: body
perform
their All
tubules the
bytwo of
help in
These medium.
: done c o n c e n t r a t i o n

ghian
tubules gland
osmosis
is osmotic
s u r T O u n d i n g

vertebrate
green

movements
by
control
the ofthe Hagfish is
a
g h i a n

glands
or actively
osmolarity osmotic

to the
Osmoconformers. cellular

and
water
that
do not according
range of
strictly wide
nnal
solute
a n i m a l s

body
fluids are a
from t
tolerate
of invertebrates

ability to
t hosmolarity
e different
its are

onformerS
of
the
freshwater

an
excellent
osmolarity,
o s m o r e g u l a t c

Osmoconformers
change
invertebrates
and
some show
maintain
an
internal

strict or
limited

fluids
within a na
a t h e r
that are body
animals
of the
c y c l o s t o m e )
invertebrates

eoontormer. are the aquatic

c o m p o s i t i o n

marine
other
hand. Many
maintain
the (Myxine,
a
onments. the they they
inhabit.
hagfish

Smoregulators, osmoregulators, i.e,

continuous

on which
arethe medium
or
m e d i u m
in however,

hypotonic
osmoreguiators

strict exception,

a concec
UTOUNding are
are in Therefore,

solute
verebrates n o t a b l e

rays). if they solution.

fish(sharks and
m a n i p u l a t i n g

The water
varnge.
excesS
h y p e r t o n i c

by
are in
Wos eliminate
gradients

Asmobranch
ASmotc
either
loss if they osmotic

maintain
must water
mOTegulators
compensate for
and verteb

in or out water
water
Environment the
fresh
animais
a
to move while water
water to mOsm
L fresh
energy

gend
rher
bodyfluids.
Fresh
Water
than
50 fluids of willbe :
body
in less
L .The
animals

much
bythe
Regulation

g e n e r a l l y mOsm faced
Solute 300
water is 200to
problem

fresh
range of
The
dbity of environment.

nsmolarities in the wat

t s u r r o u n d i n g

out
excess

their
Oetonicto
outside.
pump
that
salt to the vacuoles

Lass ofbody water.

c o n t r a c t i l e

form s
excess of
have
cover in the
Efiry of Paramoecium
body
Amoeba, s p e c i a l i s e d

include:
UZOans like animals
by
byother of salts
ions shown andloss
water water.
of of
Naimising the geain excess

salts(N
expel
needto the
reduce
the uptake conc
nO dink water to actively plasma

can and
dilute urine. NaCl
which
chloride
cells
than 1 mM
seCg of ionocytes or has
less
water (Surrounding wal water
of
Osmolarity
,takenup actively).
therefore, i n Marine E n v i r o n m e n t

mOsm
L-1,
to
tnose
opposite

Regulation in about
1000
situation
are t h e r e b y ,
they

Sually has osmolarity of marine nal

membranes). T
and
in seawater,

problems

ylts in
OSmoregulatory to
l e v e l . H o w e v e r
only. m a m m a l s

the
shell
out) or biochemical aspect of excretion, Alea
remains

(ammonia
with

or urea
can
diffuse

Ornithine
Cycle) is the caled Kreht
(The
Synthesis
and
includes

combination of ammonia, CO, and ATP.

Urea in
liver
by the
to form citrulline.
occurs phosphate

cycle, it carbamoyl ornithine

of with
Formation combines
argininosuccinic acid.
() phosphate
changes to
acid and|
Carbamoyl Th
(ü) aspartic arginine.
joins
Citruline
fumaric
acid and to urea and ornithine (which is
4.
(iüi)
breaks into
hydrolysed

latter arginine is hus, res

(v) The enzyme
arginase,

the help of
(M Withre-used in the
cycle).
Amino acid
and
2.
Transamination

CYTOSOL
Glutamate
Arginase
enzyme
Urea
NH2
HN a-keto
glutamate

NH4
Argininosuccinate
H0
lyase enzyme

2ATP HCO;

Arginine 2ADP, Pi, H*

Ornithine

Furmarate
Ornithine cycle
Carbamoy
Omithine trans phosphate
Argininósuccinate carbamoylase
+Pi

Citrulline
AMP + PPi

ATP
MITOCHONDRION

Arginino Succinate Aspartate

synthetase enzyme Transamination
Glutamate
Transamination
Amino acid

Fig. : Urea Cycle

Cor