Fluid Balance 2

• Activates angiotensin, which is converted to angiotensin II in the lungs and causes vasoconstriction and stimulates the adrenal cortext to produce aldosterone

• Increases salt and water reabsorption in the kidney (increases blood volume)
• Causes the kidneys to excrete potassium (K+)
• Has an indirect effect on water because the water follows the sodium and the sodium is affects by the aldosterone

ADH is released from the pituitary gland and causes water conservation, which increases peripheral vascular resistance and arterial BP

sodiom ions

Fluid would be pulled from the interstitial and intracellular compartments into the plasma, causing hypovolemia

Dehydration of the interstitial and intracellular compartments (low blood volume)

Fluid will move from the plasma into the interstitial and intracellular compartment (causing hypervolemia)

Baroreceptors are connected to the vagus nerve (parasympathetic) and they detect how much blood volume there is

• 1) Renin is release in the kidney when the kidney senses hypovolemia (low BP)
• 2) Renin stimulates the release of Angiotensin I, which then turns into Angiotensin II
• 3) Angiotensin II causes the retention of NA+ by the kidney (via Aldosterone), water retention by the kidney (via vasopression), increased salt appetite, increased drinking, and increased BP

• It is released as a result of atrial stretch
• Lowers BV and BP by
• -Causing vasodilation (suppressess renin-angiotensin system)
• -Decreases aldosterone (increased urinary excretion)
• -Increases glomerular filtration rate (increases rate of urine production/excretion)

• Released as a result of ventricular stretch
• Lowers BV and BP by
• -Vasodilation
• -Decreasing release of aldosterone
• -Causing diuresis of sodium/water

Triggered by a drop in BP/BV or a rist in blood osmolarity (increased blood concentration)

Causes the kidneys to absorb more water, which results in (higher vascular volume, decreased urine output)

Inhibited by a rise in BP/BV or a drop in blood osmolarity (decreased concentration)

Inhibition causes the kidneys to excrete more water in the urine, which results in lower vascular volume and high urinary output of dilute urine

• ECF volume increased
• Increase in BV and atrial distention
• Increased ANP release
• Decreased aldosterone/ADH release, decreased thirst
• Increased Na+/water loss
• homeostatsis restored

• ECF volume decreases (fluid/sodium loss)
• Decrease in BV/BP
• Increasted renin secretion and angiotensin II activation
• Increased aldosterone/ADH release
• Increased Na+/water retention, increased thirst
• Homeostasis restored

• Increased concentration of Na+ in the ECF
• Osmoreceptors stimulated
• Increased ADH release, increased thirst
• Decreased urinary water loss, increased water gain
• Additional water dilutes ECP, volume increased
• Homeostasis restored

• Decreased Na+ concentration in the ECF
• Osmoreceptors inhibited
• Decreased thirst/ADH release
• Increased urinary water loss, decreased water gain
• Water loss concentrates ECF, volume reduced
• Homeostasis restored

• Isotonic: to increase ECF
• Hypotonic: to increase ECF and rehydrate
• Hypertonic: to dehydrate cells
• Colloid: to increase plasma volume

Water moves by the concentration gradient from an area of high concentration to low concentration

The electrolytes more from an area of high concentrattion to low concentration

0.9% (isotonic)

Hypertonic: there is more salt in the solution than there is in the body (ie. 3% NS in an IV bag)

Hypotonic: there is less salt in the solution than there is in the body (ie. 0.3% NS in an IV bag)

• Normal saline (NS)
• Ringers solution
• Lactated ringer's(LR)

• Has a lower osmolarity than normal plasma
• Pulls water out of the vessels into the cells
• Results in decreased vascular volume

ie. D5W or 0.45% NS

A hypertonic solution has a higher osmolarity than normal plasma, so water is pulls from the cells into the vessels

Used to promote osmotic diuresis (rarely used; can be used for cerebral edema and to decrease intercranial pressure)

Example: 10% dextrose, 5% NS

Colloids are large solute particles that are volume expanders

Ie. Albumin (pulls fluid in and promotes osmosis into the vascular system)

• Isotonic fluid loss
• Hypertonic dehydration
• Third-spacing (ascites)

• Isotonic fluid excess
• Hypotonic fluid excess
• Synrom of inappropriate ADH (SIADH)
• Polydypsia

Acidosis: increased hydroden secretion

Alkalosis: bicarbonate and pH concentration in urine to rise

# Cations (-) # Anions= Anion Gap

low= alkalosis

high= acidosis

*normal is 9-26 mEq/L

*is commonly used in the diagnosis of metabolic acidosis

• High
• anion gap:
• DKA, starvation, lactic acidosis, renal failure

• Normal anion gap:
• Pancreatic/biliary fistulas, diuretics

• Decreased anion gap
• Hypermagnesemia