Bio1152
Chapter
44
Osmoregulation and Excretion
All organisms live in a fluid environment with different
osmotic
situations and must have adaptations for
to maintain water
balance.
Marine
animals
living in
sea water
water and
salt, so must constantly drink water and
salt.
Freshwater
animals
water and
salts from their
environment, so must constantly
dilute urine.
Nitrogenous wastes from the breakdown of
and
acids also play a role in
osmoregulation.
Many
excretory
systems maintain osmoregulation and excrete nitrogenous wastes through
by refining a filtrate derived from body fluids.
The
of a planarian filter fluids through a
, which is a network of dead-end
tubules
lacking internal openings.
The
of an earthworm consist of open-ended
tubules
that collect
fluid.
The
tubules
of terrestrial arthropods remove nitrogenous wastes from the
.
The mammalian excretory
system
consists of paired
each supplied with blood by a renal
and drained by a renal
.
hormone
(ADH) increases water reabsorption in the distal tubule and collecting duct by making them more
to water.
is another
hormone
that increases water reabsorption in the
tubule.
Review:
Control of Water Reabsorption