N105: Essentials of Nursing Care - Health Differences

Essentials of Nursing Study Guide

(crystalloids or colloids). Water is the solvent for the solutes of the body. Osmotic pressure is the power of the solution to draw water across a semi-permeable membrane. • Diffusion: This is the natural movement from an area of higher concentration to one of lower concentration. There is random movement of ions and molecules. Diffusion rate is impacted by the size of the molecule, concentration of molecule, and temperature of the solution (warm solution involves more random movement). There is an exchange of oxygen and carbon dioxide between the pulmonary capillaries and the alveoli. • Filtration: Hydrostatic pressure in the capillaries tends to filter fluid out of the vascular compartment into the interstitial fluid. Hydrostatic pressure furnished by the pumping action of the heart causes the passage of water and electrolytes from the arterial capillary bed to the interstitial fluid. Movement is from an area of higher pressure to one of lower pressure. • Active transport: This is a physiologic pump that moves fluid from an area of lower concentration to one of higher concentration. The sodium-potassium pump moves sodium from the cells to the ECF and moves potassium from the ECF to the cells. This requires adenosine triphosphate for energy. Regulating body fluids: The average adult drinks +/- 1500 mL, but needs 2500mL of fluid daily. The added volume is acquired from foods. Water content of fresh vegetables is 90%, fresh fruits 85%, and lean meats 60%. Fluid Output The routes of fluid output are: urine, insensible loss thru the skin and lungs as water vapor, noticeable loss thru the skin, and loss thru the intestines in feces. • Urine: formed by the kidneys; normal urine output for an adult is 1400-1500mL in 24 hours • Insensible loss: the loss of fluid thru the skin and lungs; normally about 300 to 400mL per day; exhaled air accounts for another 300-440mL • Feces: chyme passes from the small intestine to large intestine and contains water and electrolytes; normal volume for an adult is 1500mL per day; all but 100mL is reabsorbed in the proximal one half of the large intestines • Obligatory fluid losses: approximately 500 mL of liquid must be excreted thru the kidneys of an adult each day to eliminate metabolic waste; waster loss through respirations, skin, and feces are also obligatory losses; the total of all these losses is approximately 1300mL per day • Homeostasis: this is accomplished through the volume and composition of body fluids regulated through kidneys, endocrine system, cardiovascular, lungs, and gastrointestinal system

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