Osmoregulation Flashcards
the process of maintaining salt and water balance (osmotic balance)
across membranes within the body.
Osmoregulation
The fluids inside and surrounding cells are composed of (3)
water, electrolytes,
and nonelectrolytes.
is 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
maintains the proper balance of electrolytes in the human body, despite external factors such as temperature, diet, and weather conditions
Osmoregulation
By diffusion of water or solutes, ____ ensures that optimal concentrations of electrolytes and non-electrolytes are maintained in cells, body tissues, and interstitial fluid
osmotic balance
Classification of aquatic animals on basis of Osmotic Regulation (2)
-Osmoconformer:
-Osmoregulators
internal osmolarity nears that of the external environment
Osmoconformer:
if external conditions change, internal osmolarity changes with it.
Osmoconformer:
Maintains internal osmolarity within an narrow range regardless of the external environment.
Osmoregulators
Types of Regulation of Blood Plasma (6)
-Osmotic regulation
-Osmotic conformer
-Ionic regulation
-Ionic conformity
-Volume regulation
-Volume conformity
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
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
Osmoregulation in different Organisms (2)
- Osmoregulation in a saltwater fish
- Osmoregulation in a freshwater fish
-Gain of water and salt ions from food and by drinking seawater
-Osmotic water loss through gills and other parts of body surface
Osmoregulation in a saltwater fish
-Excretion of salt ions from gills
-Excretion of salt ions and small amounts of water in scanty urine from kidneys
Osmoregulation in a saltwater fish
-Uptake of water and some ions in food
- Uptake of salt ions by gills
Osmoregulation in a freshwater fish
-Osmotic water gain through gills and other parts of body surface
-Excretion of large amounts of water in dilute urine from kidneys
Osmoregulation in a freshwater fish
Classification based on salt tolerance (2)
Stenohaline
Euryhaline
animals that can only tolerate a narrow range of salt Concentrations
Stenohaline
animals that can tolerate widely variant osmolarities
Euryhaline
waste materials (?) excreted by animals (3)
-Ammonia
-Urea
-Uric Acid
Animals that excrete ____ need lots of water
nitrogenous wastes as ammonia
The liver of mammals and most adult amphibians converts ammonia to less toxic ____
urea
The ___ carries urea to the ___, where it is excreted
circulatory system; kidneys
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 s
Most excretory systems produce ___ by refining a filtrate derived from body fluids
urine
Key functions of most excretory systems: (4)
-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:
the functional units of the mammalian kidney (2)
Nephrons and associated blood vessels
___, the excretory organs of vertebrates, function in both excretion and osmoregulation
Kidneys
The mammalian excretory system centers on ____, which are also the principal site of water balance and salt regulation
paired kidneys
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:
outer renal cortex; inner renal medulla
the ___consists of a single long tubule and a ball of capillaries called the __
nephron; glomerulus
____occurs as blood pressure forces fluid from the blood in the ___ into the lumen of ____
Filtration; glomerulus ; Bowman’s capsule
The filtrate in ___ mirrors the concentration of solutes in blood plasma
Bowman’s capsule
From Bowman’s capsule, the filtrate passes through three regions of the nephron:
-proximal tubule
-loop of Henle
-distal tubule
Fluid from several nephrons flows into a _____
collecting duct
___ becomes urine as it flows throug the mammalian nephron and collecting duct
Filtrate
___ and ___ in the ____ change the filtrate’s volume and composition
Secretion and reabsorption in the proximal tubule
occurs as filtrate moves into the descending limb of the loop of Henle
Reabsorption of water
In the ____, salt diffuses from the permeable tubule into the interstitial fluid.
ascending limb of the loop of Henle
The ____ regulates the K+ and NaCl concentrations of body fluids
distal tubule
The ____ carries filtrate through the ___ to the ___ and reabsorbs NaCl.
collecting duct; medulla; renal pelvis;
The ___ conserves water by producing urine that is much more concentrated than body fluids.
mammalian kidney
Filtrates (7)
-H2O
-Salts (NaCl and others)
-HCO3–
-H+
-Urea
-Glucose; amino acids
-Some drugs
The action and precise arrangement of the ___ and ___ are largely responsible for the osmotic gradient that concentrates the urine.
loops of Henle; collecting ducts
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 __
osmolarity gradient; osmosis
diffuses out of the collecting duct as it traverses the inner medulla
Urea
form the osmotic gradient that enables the kidney to produce urine that is hyperosmotic to the blood
Urea and NaCl
The waste is collected in larger tubules and then leaves the kidney in the ____, which leads to the ___ where urine, the combination of waste materials and water, is stored.
ureter; bladder
The ___ contains sensory nerves, stretch receptors that signal when it needs to be emptied.
bladder
These signals create the urge to urinate, which can be voluntarily suppressed up to a limit.
sensory nerves and stretch receptors
The osmolarity of the urine is regulated by _____of water and salt reabsorption in the kidneys
nervous and hormonal control
Hormones that help regulate the needs of the body as well as the communication between the different organ systems. (7)
-epinephrine,
-norepinephrine,
-renin
-angiotensin,
-aldosterone,
-anti-diuretic hormone
-atrial natriuretic peptide
Epinephrine and Norepinephrine is produced in ____
Adrenal medulla
Renin is produced in
Kidney nephrons
Angiotensin is produced in
Liver
Aldosterone is produced in
Adrenal cortex
Anti-diuretic hormone (vasopressin is produced in
Hypothalamus (stored in the posterior pituitary)
Atrial natriuretic peptide is found in
Heart atrium
Can decrease kidney function temporarily by vasoconstriction
Epinephrine and Norepinephrine
Increases blood pressure by acting on angiotensinogen
Renin
Angiotensin II affects multiple processes and increases blood pressure
Angiotensin
Prevents loss of sodium and water
Aldosterone
hormone that Prevents water loss
Anti-diuretic hormone (vasopressin
hormone that Decreases blood pressure by acting as a vasodilator and increasing glomerular filtration rate; decreases sodium reabsorption in kidneys
Atrial natriuretic peptide
Causes nephron distal
tubules to reabsorb more
Na* and water, which
increases blood volume
Aldosterone
-Mediates insertion of aquaporins
into nephron collecting duct cells;
as a result, more water is reabsorbed into the blood
-Increases sodium reabsorption in the medulla of the kidney
Anti-diuretic hormone (vasopressin
is a hormone antagonistic to the angiotensin pathway
ANP/ Atrial natriuretic peptide
Triggers release of
other hormones
Angiotensin I
FLUID BALANCE is Controlled by ___ from the ___
ADH; post pituitary
ELECTROLYTE BALANCE Controlled by____ from the ___
Aldosterone; adrenal cortex
When the amount of water in the
body is __, ADH secretion is ___, which increases the ____ from
the distal convoluted tubule and
collecting tubule, thereby secreting a small amount of concentrated
(hypertonic) urine.
less; increased;
reabsorption of water (facultative reabsorption);
When the water intake is ___, ADH secretion is __, which makes the DCT and collecting tubule ___ to water and a large amount of ___ is excreted
more; decreased;
less permeable; dilute urine
The concentration of Na+, K+, Cl-, Ca+, Mg+, HCO3-; etc. is regulated by their ___ in the P.C.T.
increased or decreased reabsorption
.Calcium ion concentration is maintained by (2)
-CALCITONIN (thyroid gland)
-PARATHORMONE (parathyroid gland).
a hormone secreted by the
adrenal-gland helps in reabsorption of Nat by
excreting K* in exchange, in the DCT & collecting tubule
ALDOSTERONE,
___ play a major role as an excretory organ in all
vertebrates.
Kidneys
__ helps in elimination of urea; inorganic salts and water through sweat glands.
Skin
help in the elimination of CO, and H2O
Lungs
3 organs that help in the elimination of waste products
lungs, skin, kidney
