Cell bio- water balance Flashcards
life depends on maintaining what three things?
amount of body water
proportion of water and electrolytes in the water
acid-base balance
what is the charge and polarity of water and why?
neutral charge
polar= electrons are asymmetrically distributed
what is flickering cluster?
at 37C, 15% of water molecules are joined to four others
how are water molecules joined together?
transiently in a H-bond lattice
what is the cohesive nature responsible for?
unusual properties such as high surface tension and specific heat
what bond is stronger, hydrogen or covalent?
covalent
define solution, solute and solvent
solution= a substance dissolved in a liquid solute= dissolved substance solvent= the liquid
what happens to a substance when it is dissolved in water?
their molecules separate from each other, each becoming surrounded by water molecules
what are hydrophilic molecules composed of, what is their likelihood to dissolve, how do they interact with water, and what are 2 examples
composed of ions or polar molecules that attract water through electrical charge effects
dissolve readily
water molecules surround each ion or polar molecule
NaCl and urea
What are hydrophobic molecules composed of, what type of bonds do they have and how do they react with water?
contain many nonpolar bonds that are insoluble in water
hydrocarbons= C-H bonds
water molecules are not attracted to them and don’t surround them
what is molar concentration and what does it determine?
the number of osmotic active particles
osmotic pressure
what is osmotic pressure exerted by particles in a solution determined by?
the number of particles per unit volume or fluid, not by the mass of the particles
what is molarity?
the amount of a substance per unit volume (mol/L)
what is molality?
the amound of a substance per unit mass of solvent (mol/Kg H2O)
Is molarity or molality used for living organisms and why?
molality.
volume is temp dependent, so molality is used to describe the concentration of solutes in solutions
define molar?
the concentration of a substance in a liquid
what is the largest single constituent of the body, what % of the body is made up of it and what are the two locations it is found?
water
60%
ECF or ICF
how much fluid if ICF vs ECF?
2/3 ICF
1/3 ECF
water in the interstitium (interstitial fluid) is in what 3 forms?
gell (proteoglycans entrap water with them)
rivulets of free fluid
free fluid vesicles
what % of ECF is interstitial fluid, where is it found and what else is ECF made of?
80% IF
found in microscopic spaces between tissue cells
20% ECF= blood plasma
what makes up 1% or ECF, where is it found?
transcellular water
specific places:
lymph, cerebrospinal fluid, synovial fluid (joint), eyes, endolymph & perilyph (ears), glomerular filtrate (kidneys), plearual, pericardial and peritoneal fluids (between serous membranes)
what are 3 methods of water intake and 4 methods of water loss?
intake: ingested liquid, ingested food, metabolic water= by-product of respiration
loss: kidneys, sweat, lungs (vapor), GI tract (feces)
when is an animal in fluid balance?
when the amount of water gained each day is equal to the amount lost to the environment
what does the maintenance of normal fluid balance involve?
regulating body water content and distribution in the ECF and ICF
what does metabolic water volume depend on, is fluid gain due to formation of metabolic water regulated?
the level of cellular respiration which reflects the level of demand for ATP in body cells
not regulated to maintain homeostasis of body water
what is the main way to regulate body fluid gain?
adjusting the volume of preformed water intake, mainly by drinking more or less fluid
what is insensitive perspiration?
gradual movement of water across the skin and respiratory tract
what is sensible perspiration?
loss due to the secretory activities of the sweat glands
what is metabolic generation of water?
production of water within cells, primarily as a result of oxidative phosphorylation within mitochondria
what is the role of fluid compartments and fluid balance?
selectively permeability membranes separate body fluids into distinct compartments
what is the role of plasma membrane?
separate intracellular fluid from intersitial fluid of individual clels
what is the role of blood vessel walls?
divide intersitial fluid from blood plasma
what are two categories of compartments and what do they contain?
small= interior of a single cell large= combined interiors of the heart and blood vessels
what is homeostasis of fluid balance?
fluids are in constant motion from one compartment to another, though the volume of fluid in each compartment remains fairly stable
what is the role of blood for movement of body fluids?
the vehicle for transport and exchange of materials between body cells and the outside world
what is the movement of nutrients?
from food, enter the blood for distribution to tissues throughout the body
what is the movement of oxygen?
enters the lungs and then the blood
what is the movement of waste products generated by cellular metabolism?
diffuse from the cells into the blood stream, then excreted into urine, exhaled by lungs or follow some other route out of the body
what is the role of interstitial fluid in the movement of body fluids?
the go-between for exchanged between intracellular fluid and blood plasma
where does the echange between plasma and interstitial fluid occur?
across capillary walls
what are the three ways that substances enter and leave capillaries?
vesicular transport
diffusion
bulk flow
describe vesicular transport
substances in the plasma cross the capillary wall by endocytosis into an endothelial cell and then exocytosis into interstitial fluid
how frequent is vesicular transport used, and what is an example?
accounts for a tiny fraction of the exchange between plasma and interstitial fluid
exchangeable proteins
define diffusion
movement of molecules down their concentration gradient across the capillary wall
how frequent is diffusion and what are 2 exampled?
largest part of capillary exchange in most body tissue- most substances move through diffusion
exchange of )2 and CO2 between blood and lungs
independent exchange of individual solutes (glucose and AA)
define bulk flow
consists of both filtration and reabsorption
define filtration and reabsorption
filtration= netmovement of materials from the blood into interstitial fluid reabsorption= net movement of material from interstitial fluid into blood
when does filtration predominate, when does reabsorption predominate, which is used more?
filtration= at the arteriolar end of capillaries
reabsorption= at the venule end of capillaries
filtration is slightly used more