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64 terms

Osmoregulation and Excretion

STUDY
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The regulation of movement of solutes between internal fluids and the external environment
Osmoregulation
What process gets rid of nitrogenous metabolites and other waste products?
Excretion
What is the solute concentration of a solution called? Determines the movement of water across a selectively permeable membrane
osmolarity
Net flow of water is from the ________ to the ______ solution
Net flow of water is from the hypoosmotic to the hyperosmotic solution
Seen in the kidney, when the movement of water is equal in both direction is called
isoosmotic
Hypo= (less/more)
Hyper=(less/more)
hypo=less
hyper=more
Side A is hyperosmotic to side B, which side has more dissolved solutes?
Side A
A human cannot tolerate being in the ocean for 10 days because most animals are _______ and cannot tolerate substantial changes in external osmolarity
Stenohaline
______, marine invertebrates that are isoosmotic with their enviornment such as the lamprey, (do/do not) regulate their osmolarity
Osoconformer; DO NOT; uses no energy
Some marine osoconformers such as sharks try to regulate minimal solutes like ____, ___, ___
SO4-, Ca2+, Mg2+; uses very little energy
All freshwater and terrestrial animals are ______ which expend energy to control water uptake and loss
osmoregulators
Two types of osmoregulators
stenohaline
Euryhaline
What are animals called that can survive large fluctuations in external osmolarity?
Euryhaline
Marine bondy fishes are (hypoosmotic/hyperosmotic) to sea water
hypoosmotic (concentration of solutes in the sea is higher than the solutes in the cells of the fish)
Marine Fish take in food that (hypoosmotic/hyperosmotic) to itself; then the salty water diffuses out of the ____
the food is hyperosmotic (more solutes) than the fish's own body. Salts diffuse out of gills
Freshwater animals take in water by osmosis; freshwater is (hypoosmotic/hyperosmotic) to the fish
hypoosmotic
Freshwater fish loose salts by ____ and maintain water balance by excrete large amounts of dilute ____
diffusion; urine
Most aquatic animals including the bony fishes excrete what kind of nitrogenous waste? (is it toxic, how much water does it require, how much energy)
Ammonia
TOXIC
A Lot of water
Little energy
Mammals, amphibians, sharks excrete what kind of nitrogenous waste? (is it toxic, how much water does it require, how much energy)
Urea
less toxic
less water
more energy
Many reptiles, including birds, insects, land snails excrete what kind of nitrogenous waste? (is it toxic, how much water does it require, how much energy)
Least Toxic
Little water
Most energy
What combination do sea turtles excrete?
Mostly ammonia and a bit of urea
the kind of waste excrete depends on the animals evolutionary history and habitat
land vs sea turtles
embryos (need to conserve H2O, convert waste to uric acid and let it precipitate on inside of cell)
Which has more nitrogenous waste? An endotherm or ectotherm
endotherm
Which has more nitrogenous waste? a diet high in protein or a diet high in fat
high protein
4 stages of excretory process
Filtration - pressure filtering
Re absorption - reclaiming valuable solutes
Secretion - adding toxins and other solutes to the filtrate
Excretion- removing the filtrate from the system
A network of dead end tubules connected to external openings
protonephridium
Inside in the _____ are tubes of cilia and a nucleus
flame bulb
Each segment of an earthworm has a pair of open-ended
metanephridia
worms pump waste in the ______
coelem
What removes nitrogenous wastes from hemolymph and function in osmoregulation
malpighian tubules
What type of organism reabsorbs most of the water and excrete a relatively dry waste? What structure do they use?
Insects

Malpighian tubules
In Humans, where is the principal site of water balance and salt regulation?
Kidney
Liquid leaves the kidney via the
ureter
What is the basic filter unit of the kidney
the nephron
The renal collecting duct is located in the
medulla and travels down to pelvis
Organisms which water conservation is essential will have all _______ nephrons to conserve H2O
juxtamedullary nephrons (they extend far down into the medulla)
The majority of most nephrons are ____, existing only on the renal cortex
cortical nephrons
Filtration occurs when blood pressure forces fluid from the blood in the ______ into the lumen of the ________
glomererulus; bowmans capsule
The filtrate contains all of the following except
Salts, Amino Acids, Proteins and cells, Vitamins, Nitrogenous Wastes
NEVER contains proteins or cells (bicarbonate and potassium ions are pulled back in)
The Pathway of the Filtrate: 3 regions
1. the proximal tubules
2. The loop of Henle
3. the distal tubule
Elimination of waste is due to
blood pressure
Fluid from several nephrons flows into a _______, which lead to the renal______, which is drained by the
Fluid from several nephrons flows into a collecting duct, which lead to the renal pelvis, which is drained by the ureter
What are the capillaries that serve the loop of henle
vasa recta
What two structures function as the counter current system
Vasa Recta and the Loop of Henle
The mammalian kidney conserves water by producing ______ which is much (less/more) concentrated than body fluids
Urine; more concentrated than body fluids
The filtrate volume begins to decrease and reabsorption of water, ions, and nutrients takes place where
the proximal tubule
The filtrate becomes increasingly concentrated in the
descending limb of the loop of henle
The filtrate becomes dilute; Salt, but not water, is able to diffuse from the tubule into the interstitial fluid in the
ascending limb of the loop of henle
What regulates the K+ and NaCl concentrations of body fluids
Distal Tubule
Would you expect the volume of filtrate to be more or less in the distal tubule compared to the proximal tubule ?
MUCH less volume in the distal tubule (because body reabsorbed a lot of water by this point)
When you exercise the amount of urine you produce goes (up/down) because the collecting duct is reabsorbing water and salt
DOWN
Urine is (Hyperosmotic/hypoosmotic) to body fluids
Hyperosmotic
What controls the collecting duct
hormones
Deep in the medulla, the osmolarity is very (high/low) and salt diffuses easily
high (see diagram pg 11)
What increases water reabsorption in the distal tubules and collecting ducts in the kidney?
Antidiuretic Hormone (ADH) - it increases awuaporins and cells are more permeable to water and cells are sucked back in=less urine
An increase in blood _______ triggers the release of ADH, which prevents loss of water
osmolarity
ADH is made where and stored where
made in the hypothalamus
stored in the posterior pituitary
What reduced blood osmolarity to a set point (see diagram on pg 12)
Drinking (thirst)
A longer loop of henle means
extreme water conservation ( an animal in a desert will have a long loop of henle and an animal in freshwater will have a short loop)
Birds, which short loops of henle, conserve water by
excreting uric acid instead of urea
Reptiles only have cortical nephrons but also excrete nitrogenous waste as
uric acid
Freshwater Fishes conserve their salt in _____ and excrete large volumes of ___
Distal tubules, dilute urine
Amphibians and _____ have similar kidneys. Amphibians conserve water on land by reaborbing water from the ______
freshwater fish; urinary bladder
Marine Bony fishes are (hyperosmotic/hypoosmotic) compared with their enviornment and exrete (alot/little) urine
Hypoosmotic/little