13 to 15: Osmoregulation Flashcards
How is the water balance maintained in the body?
What goes in the body must be used up or excreted. Eg diet, environment, behavior, thermoregulation
Input + production = utilization + output
Water gains: metabolic water
What is metabolic water
Water gains: metabolic water
Water generated as a result of oxidative phosphorylation
Ie carbs –> energy –> water
Dessert animals like small mice are highly dependent on metabolic water.
Eg camels store fat in their humps, to gain water they metabolism this fat
Water gains- preformed water
What is it and how do you get it?
It is water associated with food Ie dry seeds -5-10% Insects, meat 60-70% Green Pasture 80-90% What you eat will determine your preformed water intake
Water gains: electrolytes
By regulating their electrolyte concentration, cells can control their water content (through osmosis)
Main solutes:
K and HCO in intracellular fluid
Na and Cl in extracellular fluid
Electrolytes: classification of solutes
Distinguished by their effects on macromolecules
Perturbing:
-disrupt macromolecule functions
-Na, Cl, K, SO4+, charged amino acids
-known to increase the Km of an enzyme
Compatible:
-little effect
-polyols (glycerol, glucose) and uncharged amino acids
Counteracting:
-disrupt function on their own, but counteract disruptive effects of another solute when employed in combination
-urea disrupts and methylamines strengthen hydrophobic interactions; together there is little effect
How many moles in 9 grams of NaCl?
1 mole= 6.02 x 10^23 Then use: n=m/M Need molecular mass= 58.5 9/58.5 = .154 moles of NaCl
Molarity: number of moles of a solute psent in 1 litre of solution.
Calculate the concentration (mol/L) when 9 grams NaCl is dissolves in 1L of water
N=c/v????
If the NaCl dissociates it will be an electrolyte, because they are charged molecules
The total osmotic activity in a solution is the sum of the individual osmotic activities of ll solutes in the solution
What is the osmolarity if 0.9% NaCl
0.154mol Na + 0.154 mol of Cl etc etc refer tonsoide
What is the difference between non-electrolytes and electrolytes?
Calculating their osmoles
Non electrolytes:
Covalent bonds that prevent dissociation in solution, so that no electrically charged species occur when they dissolve in water (mostly organic molecules)
Number of osmoles = number of moles
Electrolytes:
-Chemical compounds that dissociate in water into ions, and because ions are charged, then electricity can be conducted
-typically include inorganic salts, inorganic and organic acids and bases, and some proteins
-number of osmoles = sum of the number of moles of each electrolyte
Ie (solid)NaCl + H2O –> (ions) Na+ + Cl-
The total osmotic activity in a solution is the sum of the individual osmotic activities of all the solutes in the solution.
What is the osmolarity of 0.9% NaCl
??? Will do in class
Outputs: Nitrogen excretion
When amino acids are oxidized or converted to other kinds of molecules, the amino (NH2) group must be removed.
- nitrogenous wastes are ammonia, urea, or Utica acid (they are toxic and must be broken down) they are excreted in 3 forms
1. Ammonia
2. Urea
3. Uric acid
Outputs: nitrogen excretion- ammonia
What are the advantages and disadvantages
Advantages:
- direct end-product deanimation of amino acids, therefore the process requires no additional energy cost
- highly soluble in water
Disadvantages:
- very toxic- requires 400ml of water to dilute each gram to a non-toxic concentration
- must be excreted rapidly or converted to a less toxic form (eg uric acid or urea)
Outputs: nitrogen excretion- urea
What are the advantages and disadvantages
Advantages:
- less toxic than ammonia, doesn’t need as much water to dilute it which makes it for better storage
- highly soluble: can be moderately concentrated to conserve water
Disadvantages:
- requires more energy to produce than ammonia does
- a fair amount of water needed for its storage and excretion
Outputs: nitrogen excretion -uric acid
What are the advantages and disadvantages?
Advantages:
- can be produced in a concentrated crystal form which saves water
- low toxicity- 50x less water for storage and excretion at non toxic concentrations
- can be stored
Disadvantages:
-synthesis of uric acid requires more energy than urea synthesis
Vertebrate kidneys have 6 roles what are they?
-ion balance-osmotic balance
-blood pressure
Ph balance
Excretion
Hormone regulatio
One of the earliest signs of kidney failure in cats and dogs is incontinence what is it?
-kidney lose their ability to concentrate the urine effectively- reduced water reabsorption
