OSMOREGULATION: SALT AND ELECTROLYTES EXCRETION Flashcards
process of maintaining salt and water balance
(osmotic balance) across membranes within the body
Osmoregulation
fluids inside and
surrounding cells are
composed of?
water,
electrolytes, and
nonelectrolytes
based largely on controlled
movement of solutes between internal fluids and
the external environment
Osmoregulation
expend energy to control water
uptake and loss in a hyperosmotic or hypoosmotic
environment
Osmoregulators
Osmoregulation maintains the proper balance
of electrolytes in the human body, ____ such as temperature, diet, and
weather conditions
despite
external factors
By ____, osmotic balance
ensures that optimal concentrations of
electrolytes and non-electrolytes are maintained
in cells, body tissues, and interstitial fluid
diffusion of water or solutes
- internal osmolarity nears that of the external environment
- if external conditions change, internal osmolarity changes
with it.
Osmoconformer
- Maintains internal osmolarity within an narrow range regardless of the external environment.
- Depending on conditions, the animal could have an
osmolarity higher or lower than surrounding water.
Osmoregulators
Types of Regulation of Blood Plasma
osmotic regulation
osmotic conformer
ionic regulation
maintains
a constant or nearly constant osmotic pressure
in the blood plasma
Osmotic regulation (osmoregulation)
the blood osmotic
pressure always equals the osmotic pressure of
the environmental water
Osmotic conformer
maintains of a constant or
nearly constant concentration of an inorganic ion
in the blood plasma
Ionic regulation
Types of Osmotic regulation and
Conformity
ionic conformity
volume regulation
volume conformity
allows the concentration of
the ion in its blood plasma to match the
concentration in its external environment.
Ionic conformity
is the regulation of the total
amount of water in a body fluid
Volume regulation
refers to completely
passive changes
Volume conformity
Classification based on salt
tolerance
stenohaline
euryhaline
animals that can only tolerate a
narrow range of salt Concentrations
Stenohaline
animals that can tolerate widely
variant osmolarities
Euryhaline
amine group that is released across the whole
body surface or through gills
Ammonia
Animals that excrete nitrogenous wastes
as ammonia need lots of water
The liver of ____ and most adult ____ converts ammonia to less toxic urea
mammals
amphibians
The circulatory system carries urea to the
kidneys, where it is excreted
4 organisms that excrete uric acid
Insects, land snails, and many reptiles,
including birds mainly excrete uric acid
is largely insoluble in water and can be secreted as a paste with little water loss
Uric acid
Excretory Processes in
Mammals
filtration
reabsorption
secretion
excretion
pressure-filtering of body fluids
Filtration
reclaiming valuable solutes
Reabsorption
adding toxins and other solutes from the
body fluids to the filtrate
Secretion
removing the filtrate from the system
Excretion
excretory organs of vertebrates, function in
both excretion and osmoregulation
kidneys
The mammalian excretory system centers on paired
kidneys, which are also the principal site of _____
water balance
and salt regulation
Each kidney is supplied with blood by a ____ and
drained by a ____
renal artery
renal vein
Urine exits each kidney through a duct called the
ureter
Both ureters drain into a common
urinary bladder
mammalian kidney has two distinct regions
an outer renal cortex and an inner renal medulla
consists of a single long tubule and a
ball of capillaries called the _____
nephrons
glomerulus
Filtration occurs as blood pressure forces fluid
from the blood in the glomerulus into the lumen of
____
Bowman’s capsule
The filtrate in Bowman’s capsule mirrors the
concentration of _____
solutes in blood plasma
From Bowman’s capsule, the filtrate passes
through three regions of the nephron?
proximal tubule, the loop of Henle, and the
distal tubule
Fluid from several nephrons flows into a
_____
collecting duct
Secretion and reabsorption in the ____
change the filtrate’s volume and composition
proximal tubule
Reabsorption of water occurs as filtrate moves into
the ____
descending limb of the loop of Henle
In the ascending limb of the loop of Henle, salt
diffuses from the ____
permeable tubule into the
interstitial fluid.
regulates the K+ and NaCl
concentrations of body fluids.
The distal tubule
carries filtrate through the
medulla to the renal pelvis and reabsorbs NaCl
The collecting duct
The mammalian kidney conserves water by
producing urine that is ____
than body fluids.
much more concentrated
The action and precise arrangement of the loops
of Henle and collecting ducts are largely
responsible for the ____ that
concentrates the urine.
osmotic gradient
____ contribute to the osmolarity of the
interstitial fluid, which causes reabsorption of
water in the kidney and concentrates the urine
NaCl and urea
The collecting duct conducts filtrate through the
____, and more water exits the
filtrate by osmosis
osmolarity gradient
Urea diffuses out of the collecting duct as it
traverses the ____
inner medulla
Urea and NaCl form the osmotic gradient that
enables the kidney to produce urine that is
____ to the blood
hyperosmotic
The waste is collected in _____ and then
leaves the kidney in the ureter, which leads to
the bladder where urine, the combination of
waste materials and water, is stored.
larger tubules
The bladder contains _____, stretch receptors that signal when it needs to be emptied.
* These signals create the urge to urinate, which
can be voluntarily suppressed up to a limit.
sensory nerves
The osmolarity of the urine is regulated by
_____
nervous and hormonal control of water and salt
reabsorption in the kidneys
6 hormones that help regulate the needs of the body as well as the communication between the different organ
systems.
epinephrine
norepinephrine
renin-angiotensin
aldosterone
anti-diuretic hormone
atrial natriuretic peptide
organ: Epinephrine
and
Norepinephrine
Adrenal
medulla
organ: renin
Kidney
nephrons
organ: angiotensin
liver
function: epinephrine and norepinephrine
Can decrease kidney function temporarily by vasoconstriction
function: renin
Increases blood
pressure by acting on
angiotensinogen
function: angiotensin
Angiotensin II affects
multiple processes
and increases blood
pressure
organ: aldosterone
Adrenal
cortex
organ: atrial natriuretic peptide
heart atrium
organ: anti-diuretic hormone (vasopressin
hypothalamus
function: aldosterone
Prevents loss of sodium
and water
function: ADH
prevents water loss
function: ANP
Decreases blood pressure by acting as a vasodilator and increasing glomerular filtration rate; decreases sodium reabsorption in kidneys
angiotensin to angiotensin I
renin
angiotensin I to angiotensin II
angiotensin converting enzyme
