Body Fluid Balance Flashcards
List the main sources of water gain and the amount that they typically constitute
List the main sources of water loss and the amounts that they typically constitute
What is osmosis?
Osmosis is the passive movement of water across a partially permeable membrane
In what direction does water move in osmosis?
From an area of high water concentration to an area of low water concentration (along the water concentration gradient)
From an area of lower solute concentration to an area of high solute concentration to which the membrane is impermeable
What are the causes of dehydration?
ECF hypertonicity occurs when the proportion of water to solutes is lowered
Caused by insufficient water intake and excessive water loss (due to vomiting, diarrhea, sweating)
How does the body correct for dehydration?
ECF hypertonicity increases:
1. Thirst centers in the hypothalamus are stimulated
2. ADH is secreted → decreases urine volume by increasing water reabsorption in kidney
What are the causes of overhydration?
ECF hypotonicity occurs when the proportion of water to solutes is increased.
Caused by rapid ingestion of water
What are the methods of correcting for overhydration?
ECF hypotonicity causes:
1. Thirst centers in the hypothalamus are inhibited
2. ADH is inhibited → increase urine volume by decreasing water reabsorption in kidney
What factors increase and decrease ADH secretion?
What factors increase and decrease thirst sensation?
What are the hazards of ECF hypotonicity?
Water intoxication occurs - water moves from the ECF to cells leading to swelling of cells
What are the hazards of ECF hypertonicity?
Water moves out from the cells, leading to shrinkage of cells
Which cells are most impacted by alterations in water regulation?
Brain cells
Altered neurological functions including nausea, malaise, headache, confusion, lethargy, seizures, coma and death may occur
