Bio2 Chapt44 Osmoregulation and excretion Flashcards
What controls solute conc and balances water gain and loss
osmoregulation
What type of animals survive by conserving solutes and absorbing salts from their surroundings
Freshwater animals
What animals face desiccating environments that can quickly deplete body water
desert and marine animals
What gets rid of the nitrogenuos metabolites and other waste products
excretion
What is based largely on balancing the uptake and loss of water and solutes
osmoregulation
What is the driving force for movement of solutes and water in osmoregulation
conc gradient of one or more solutes across the plasma membrane
What can greatly affect an animals water balance
type and quantity of the waste products
What are the most significant wastes are nitrogenous breakdown of..
protiens and nucleic acids
What can some animals convert ammonia to
less toxic compounds before excretion
3 types of nitrogeneous waste
ammonia, urea and uric acid
The diffrent nitrogenous wastes in diffrent forms differ in
toxicity and the energy costs of producing them
What does ammonia need lots of to excrete
water
Most to least toxic, ammonia, urea and uric acid
ammonia, urea and uric acid
What do most terrestrial mammals and many marine species excerte
urea
Where are vertabrates urea produced
in the liver
The circulatory system brings urea to where to be excreted
kidneys
Why do animals convert ammonia to urea, and why is it hard
it requires less water and is less toxic, but it takes lots of energy
What do insects, land snails, many reptiles, and birds mainly excrete?
uric acid
is uric acid toxic
not really
Compared to urea, is uric acid more or less energetically expensive to produce?
Uric acid is more energetically expensive to produce than urea.
does uric acid dissolve well in water, and what does that cause
it doesnt, so its excreted in a paste or solid.
What do excertory system regulate
solute movement between internal fluids and external enviroment
Why are excertory systems important for homeostasis
they control balance of water and solutes in the body
Most excretory systems produce urine by refining a f—– derived from body fluids
filtrate
Filtration
filtering of body fluids
Reabsorption
reclaiming valuable solutes
Secretion
Adding nonessential solutes and wastes to the filtrate
Excretion
processed filtrate containing nitrogenuous wastes is released from body
What is the excretory organ of vertebrates
kidney
What are the structures inside kidneys that help with excretion?
lots of highly organized tubles
Besides the kidneys, what does the vertebrate excretory system include?
ducts and other structures that carry urine from the tubules out of the body.
What does the filtrate produced in bowmans capsule contain
salts, glucose, amino acids, vitamins,
nitrogenous wastes, and other small molecules
Where does reabsorption of ions, water, and nutrients occur in the nephron?
In the proximal tubule.
How are molecules reabsorbed from the filtrate in the proximal tubule?
Through both active and passive transport into the interstitial fluid and then capillaries.
What happens to materials to be excreted as filtrate moves through the proximal tubule?
becomes concentrated
What happens to some toxic materials in the proximal tubule?
actively secreted into the filtrate
What continues in the descending limb of the loop of Henle?
reabsorb water
What allows water to be absorbed in the descending limb
chennels formed by aquaporin protiens
What drives water movement out of the filtrate in the descending limb?
The high osmolarity of the interstitial fluid, which is hyperosmotic to the filtrate.
What happens to the filtrate as it moves down the descending limb
increasingly concentrated
What is reabsorbed in the ascending limb of the loop of Henle?
salt
can water diffuse out of the ascending limb
no, only salt can diffuse out, not water
What happens to the filtrate as it moves up the ascending limb?
more and more diluted
what does the distal tube regulate
conc of potassium and sodium chloride in body fluids
how does the distal tubule contribute to PH balance
through the controlled movement of H and bicarbonate ions
Where does the collecting duct carry filtrate
through the medulla to the renal pelvis
What is one of the most important main function of collecting duct
reabsorbtion of solutes and water
is urine more or less conc than body fluids
more conc (HYPEROSMOTIC)
What happens to filtrate volume in the proximal tubule? And What happens to the osmolarity?
Filtrate vol decreases as water and salt are reabsorbed, osmolarity stays the same
What happens to water and concentration of the filtrate in the descending limb of the loop of henle
Water leaves the tuble, via osmosis, so the filtrate gets more conc
What maintains high osmolarity in the renal medulla
NaCl diffusing out of the ascending limb of the loop of henle
What is the primary function of the vertebrate kidney?
Osmoregulation—maintaining water and salt balance, and excreting nitrogenous wastes.
How does nephron structure vary among vertebrates in different environments?
Nephrons vary in length and permeability to adjust for water conservation or excretion based on habitat.
What type of nephron is most efficient for water conservation? And why
Juxtamedullary nephrons, which have long loops of Henle that concentrate urine effectively.
How are kidneys adapted in freshwater fish?
They have many nephrons with large glomeruli to excrete excess water and reabsorb salts.
How are kidneys adapted in marine bony fish?
They have fewer or no glomeruli to conserve water, and actively excrete salts through gills and urine.
What kidney adaptation is seen in desert mammals?
Very long loops of Henle for maximum water reabsorption and highly concentrated urine.
Why do amphibians have relatively short loops of Henle?
they live in moist enviroments and dont need to conc urine as much
How do birds conserve water despite producing uric acid?
They reabsorb water in the cloaca and produce uric acid, which is excreted as a paste with minimal water loss.
What is the benefit of producing uric acid over urea or ammonia?
Uric acid is less toxic and requires little water to excrete, ideal for dry environments.
What type of nephron is key to water conservation in terrestrial mammals
juxtamedullary nephron
What feature allows the juxtamedullary nephron to conserve water? IN MAMMALS
long loop of henle that creates a strong osmotic gradient to conc urine
How does nephron structure differ in mammals from dry environments?
very long loops of henle to maximize water absorbtion
What does a shorter loop of Henle in freshwater mammals indicate?
Less need for water conservation; more water is excreted in the urine.
What does the vampire bat illustrate about the mammalian kidney? (as it feeds on blood of mammals at night)
The versatility of the mammalian kidney.
What unique ability does the vampire bat have regarding urine production?
It can alternate rapidly between producing large amounts of dilute urine and small amounts of very hyperosmotic urine.
Why is the vampire bat’s ability to switch urine concentration important?
It helps balance fluid load after feeding and conserve water when not feeding.
What is another name for antidiuretic hormone (ADH)?
vasopressin
Where are osmoreceptor cells that monitor blood osmolarity located?
In the hypothalamus
What do osmoreceptor cells regulate?
The release of ADH from the posterior pituitary.
What happens when blood osmolarity rises above its set point?
ADH release into the bloodstream increases.
What is antidiuretic hormone (ADH)?
ADH is a hormone that helps the body conserve water by making the kidneys reabsorb more water, reducing urine volume and increasing urine concentration.
Excretion process from what to what
Filtration, Reabsorption, Secretion and then excretion
FAST RABBITS STAY ENERGETIC
Nepheron structure, what to what
Bowmans capsule, convoluted tubules, Loop of Henle, Distal tubule, collecting duct
BOWMANS CRAZY LITTLE DOG COLLECTS PAWS
Job of bowmans capsule
filtrate
Concoluted tubles job
reabsorb H2O, glucose and amino acids
Loop of henles job, descending and ascending
DECENDING- enter H2O
ASCENDING- enter salt
Distal tubule job
secretion
Collecting duct job
final checkpoint of water absorption
