201 D Exam 4: Water balance
ADH Secretion Regulation and Action
⬆️Osmolality,⬇️Body fluid,⬇️BP = Stims Osmoreceptors -Release ADH (Vasopressin)= -H2O kidney retention -Decrease sweat -Constrict Arterioles = -Stop when ⬇️ Osmolality
Of the 60% of water that makes up our body, where is it stored?
-2/3 in the Intracellular -1/3 in extracellular: 20% plasma 80% interstitial.
What are s/sx of hypervolemia?
-Incr BP -Crackles in Lungs, dyspnea -Polyuria (straw color) -Weight gain
What are some causes of hypervolemia?
-Incr hydrostatic pressure via IV fluids -Excess fluid intake -Low albumin levels (decr oncotic pressure)
Where does hydrostatic pressure drive the water in the body?
-It drives it from the ECF to the ICF -It is an outward force.
What is osmotic pressure?
-It is the pulling force of H2O exerted by the solutes--mainly sodium
Why do older people have less water content?
-Less muscle mass, More fat -Decreased renal function -Decreased thirst
What are some mechanisms that kick in to cue us into the fact that we might be dehydrated?
-Osmoreceptors that stimulate the hypothalamus: Thirst -Renin-angiotensin-aldosterone system-aka RAAS. -Release of ADH
What is the difference between insensible and sensible water loss.
-Sensible loss is measurable EX: urine, vomiting, exercise. -Insensible loss in not measurable EX: sweat and respiration.
What are some assessment points for hypervolemia?
-VS -Lungs and heart -I&O urine color, specific gravity, quantity -Labs - Na, BUN, Hct
What causes third spacing?
-liver disease & renal disease -Low albumin level d/t malabsorption in small intestine/colon
Edema causes:
-⬆️venous hydrostatic pressure (ie.,fluid overload) -⬇️plasma oncotic pressure (ie.,low plasma protein) -⬆️interstitial oncotic pressure (ie., accumulation of protein in interstitial space)
1 oz = ______mL
30
What percent of our body is water? Solid?
60%/ 40%
What would a low level of albumin lead to?
A diminished pulling force. So, fluid will stay in the cells becuase the hydrostatic pressure is stronger.
Why do obese individuals have a lower percentage of H2O in the body?
Becuase they have more adipose tissue which doesn't store water as well as muscle.
Where does osmotic pressure drive the water in the body?
It drives/pulls the water from the ICF to the ECF-intravascular
What is oncotic pressure?
It is another pulling force of water that is exerted by albumin.
What is dehydration?
Loss of water only
Who has higher levels of H2O volume and why?
Males do becuase they tend to have more lean muscle mass. Lean muscle stores water better than fat tisssue.
What releases ADH?
Posterior pituitary gland
What is hypovolemia?
The loss of both H2O and solutes/electrolytes.
With a decrease in colloidal osmotic pressure, where does fluid accumulate?
in interstitial and nonfunctional areas
I kg = _______L
1 L
