one side of a membrane pulls water from the other
side
Hydrostatic Pressure
blood pressure that forces water out of the
capillaries into the interstitial space
Oncotic Pressure
pressure exerted by the concentration of solutes on
one side of a membrane pulls water from the other
side
Effective Arterial Blood Volume
EABV- amt of blood in the arterial space to
effectively perfuse organs/tissue. Changes in ECF
will cause this to change. Decrease ECF vol. =
EABV decrease.
Antidiuretic Hormone
A relatively small (peptide) molecule that is
released by the pituitary gland at the base of the
brain after being made nearby (in the
hypothalamus).
In response to a water deficit,
sodium excess or low BP. ADH has an antidiuretic
action that prevents the production of dilute urine
(and so is antidiuretic). ... ADH is also known as
vasopressin. Kidneys reabsorb water = more plasma
volume
Renin Angiotensin Aldosterone System
a hormone system that regulates blood pressure and
fluid balance. ... This increases the volume of
extracellular fluid in the body, which also increases
blood pressure. It is activated by low blood volume,
renin converts to angiotensinogen to angiotensin I –
water is retained = less urine = increases blood vol.
Natriuretic Hormones
Released from the atria or ventricle of the heart they
work opposite of RAAS to decrease blood volume,
promote urine excretion of NA+ and H2O (ANP &
BNP)
Tonicity
relative concentration of solute; ability of a solution
to cause a cell to gain or lose water
Isotonic
equal in concentration of solute molecules
Hypotonic
having a lesser concentration of solute molecules –
c.Evaluate the purpose, function and role of hydrostatic and oncotic pressure and describe the mechanisms by which they are altered.
