Summary NR 324 week 1 chapter 16 and 25 fluid and electrolyte balance.Download to score A.

Fluid and electrolyte balance is a dynamic process that is crucial for life and homeostasis. Fluid occupies almost 60% of the weight of an adult. Body fluid is located in two fluid compartments: the intracellular space and the extracellular space. Electrolytes in body fluids are active chemicals or cations that carry positive charges and anions that carry negative charges. The major cations in the body fluid are sodium, potassium, calcium, magnesium, and hydrogen ions. The major anions are chloride, bicarbonate, sulfate, and proteinate ions. Homeostasis Homeostasis is the dynamic process in which the body maintains balance by constantly adjusting to internal and external stimuli. Negative and Positive Feedback Feedback is the relaying of information about a given condition to the appropriate organ or system. Negative feedback. Negative feedback occurs when the body reverses an original stimulus for the body to regain physiologic balance. Positive feedback. Positive feedback enhances or intensifies the original stimulus. Examples. Blood pressure control and maintenance of normal body temperature are examples of negative feedback while blood clotting after an injury and a woman in labor are examples of positive feedback. Systems Involved in Feedback The major systems involved in feedback are the nervous and endocrine systems. Nervous system. The nervous system regulates homeostasis by sensing system deviations and sending nerve impulses to appropriate organs. Endocrine system. The endocrine system uses the release and action of hormones to maintain homeostasis. Body Fluids Fluids make up a large portion of the body, which is approximately 50%-60% of the total body weight. ADVERTISEMENT Location of Fluids Main compartments. Body fluids are divided between two main compartments: the intracellular fluid and the extracellular fluid compartments. Intracellular fluid. Intracellular fluid functions as a stabilizing agent for the parts of the cell, helps maintain cell shape, and assists with transport of nutrients across the cell membrane, in and out of the cell. Extracellular fluid. Extracellular fluid mostly appears as interstitial tissue fluid and intravascular fluid. Fluid Regulation Mechanisms The thirst center. The thirst center in the hypothalamus stimulates or inhibits the desire for a person to drink. Antidiuretic hormone. ADH regulates the amount of water the kidney tubules absorb and is released in response to low blood volume or in response to an increase in concentration of sodium and other solutes in the intravascular fluids. The RAA system. The RAA system controls fluid volume, in which when the blood volume decreases, blood flow to the renal juxtaglomerular apparatus is reduced, thereby activating the RAA system. Atrial natriuretic peptide. The heart also plays a role in correcting overload imbalances, by releasing ANP from the right atrium. Normal Intake and Output Daily intake. An adult human at rest takes appropriately 2,500 ml of fluid daily. Levels of intake. Approximate levels of intake include fluids 1, 200 ml, foods 1, 000 ml, and metabolic products 30 ml. Daily output. Daily output should approximately equal in intake. Normal output. Normal output occurs as urine, breathing, perspiration, feces, and in minimal amounts of vaginal secretions. Overhydration and Edema Overhydration. Overhydration is an excess of water in the body. Edema. Edema is the excess accumulation of fluid in interstitial tissue spaces, also called third-space fluid. Cause of edema. Edema is caused by a disruption of the filtration and osmotic forces of the body’s circulating fluids. Treatment of edema. Diuretics are commonly given for systemic edema. Dehydration Dehydration. Dehydration is a deficiency of body water or excessive loss of water. External causes. External causes of dehydration include prolonged sun exposure and excessive exercise, as well as diarrhea, vomiting, and burns. Treatment of dehydration. Supplemental fluids and electrolytes are often administered. Electrolytes An electrolyte is a substance that will disassociate into ions when dissolved in water. Origins. Electrolytes are found in the form of inorganic salts, acids, and bases. Active chemicals. Electrolyte concentrations are measured according to their chemical activity and expressed as milliequivalents. Ions. Each chemical element has an electrical charge, either positive or negative. Intracellular electrolytes. Important intracellular electrolytes are potassium, magnesium, sulfate, and phosphate, and the most dominant cation iss potassium while the most dominant anion is phosphate. Extracellular electrolytes. Important extracellular electrolytes include sodium, chlorine, calcium, and bicarbonate, and the most essential cation is sodium while chlorine is the most important anion. Fluid and Electrolyte Transport Total electrolyte concentration affects the body’s fluid balance. The body cells. Nutrients and oxygen should enter body cells while waste products should exit the body. The cell membrane. The cell membrane separates the intracellular environment from the extracellular environment. Permeability. The ability of a membrane