So let's look at disorders of water balance.
There are three principal abnormalities of water balance.
The first is dehydration.
Extracellular fluid water loss can be due to things like
hemorrhage,
severe burns,
prolonged vomiting or diarrhea,
profuse sweating,
water deprivation,
diuretic abuse,
or endocrine disturbances.
Signs and symptoms of dehydration include
a cottony oral mucosa or cottonmouth,
thirst,
dry flushed skin,
or oliguria.
This may also lead to weight loss,
fever,
mental confusion,
hypovolemic shock,
and loss of electrolytes from the body.
The consequences of dehydration
are that as solutes are loss the cells in our body will shrink.
This happens because the excessive loss of water
from our extracellular fluid
means that the extracellular osmotic pressure
is going to rise.
In response to this rise in osmotic pressure,
the cells will lose water to the extracellular fluid by osmosis.
As the water leaves the cells and goes into the extracellular fluid,
our cells will shrink.
The second disorder of water balance is going to be
hypotonic hydration.
This is also sometimes referred to as water intoxication
or cellular over hydration.
This can occur when there's a renal insufficiency,
but more likely this occurs
when there is rapid excess water ingestion,
such as if you were having in a contest,
a water drinking contest
and that contestants were trying to drink as much water
as fast as possible.
The extracellular fluid osmolality is going to drop
and this is going to cause a condition known as hyponatremia,
or low sodium levels.
This results in a net osmosis of water
into our tissue cells, causing our cells to swell.
Symptoms of hypotonic hydration includes:
severe metabolic disturbances,
nausea,
vomiting,
muscular cramping,
cerebral edema,
and also possibly death.
This is treated by administering a hypertonic saline solution,
which will then pull the fluid back out of the cells
toward the extracellular fluid compartment.
The consequences of hypotonic hydration include
when the water and solutes are going into the cells,
the cells will begin to swell.
This is due to excessive water
entering the extracellular fluid compartment,
which causes the osmotic pressure of the extracellular fluid to fall.
Because of this pressure change,
water will now move into the cells by osmosis,
leading to the swelling of the cells.
The third disorder of water balance is edema.
This is an atypical accumulation of our interstitial fluid,
resulting in the swelling of our tissues.
Please note that this is not the swelling of cells
that we saw with water intoxication,
and only the volume of the interstitial fluid is increased
and not the other compartments.
This can impair tissue function by increasing the distance
for diffusion of oxygen and nutrients
from the blood into the cells
as it increases the distance between these cells
and the blood capillaries.
This could be caused by an increased fluid flow out of the blood
or a decreased return to of the fluid back into the blood.