fluid balance

balance /bal·ance/ (bal´ans)

1. an instrument for weighing.

2. equilibrium.

---

acid-base balance  a normal balance between production and excretion of acid or alkali by the body, resulting in a stable concentration of H+ in body fluids.

analytical balance  a balance used in the laboratory, sensitive to variations of the order of 0.05 to 0.1 mg.

fluid balance  the state of the body in relation to ingestion and excretion of water and electrolytes.

nitrogen balance  the state of the body in regard to ingestion and excretion of nitrogen. In negative nitrogen b. the amount excreted is greater than the quantity ingested; in positive nitrogen b. the amount excreted is smaller than the quantity ingested.

water balance  fluid b.

---

fluid balance

n.

The difference between the amount of water taken into the body and the amount excreted or lost. Also called water balance.

---

balance

1. an instrument for weighing.

2. harmonious adjustment of different elements or parts; harmonious performance of functions. Used to describe symmetry and proportion of conformation.

---

acid-base balance

the proportion of acid and base required to keep the blood and body fluids neutral. See also acid-base balance.

analytical balance

a laboratory balance sensitive to very small variations of the order of 0.001 mg.

balance examination

simultaneous palpation of muscles on both sides of the body of Greyhounds attempting to locate areas of soreness or spasm.

fluid balance

the state of the body in relation to ingestion and excretion of water and electrolytes (see also fluid balance).

nitrogen balance

the state of the body in regard to ingestion and excretion of nitrogen. In negative nitrogen balance the amount of nitrogen excreted is greater than the quantity ingested. In positive nitrogen balance the amount excreted is smaller than the amount ingested. See also nitrogen balance.

posture balance

disturbances of balance, including falling to one side, rotation of the head, walking in circles. These are usually indications of disturbances of the organs of balance in the semicircular canals.

water balance

fluid balance.

---

fluid

1. a liquid or gas; any liquid of the body.

2. composed of molecules which freely change their relative positions without separation of the mass.

---

allantoic fluid

the fluid contained within the allantois.

amniotic fluid

the fluid within the amnion that bathes the developing fetus and protects it from mechanical injury.

ascitic fluid

see ascites.

fluid balance

a state in which the volume of body water and its solutes (electrolytes and nonelectrolytes) are within normal limits and there is normal distribution of fluids within the intracellular and extracellular compartments. The total volume of body fluids should be about 60% of the body weight, and it should be distributed so that one-third is extracellular fluid and two-thirds intracellular fluid. Although this distribution remains constant in a healthy animal, there is continuous movement of fluid into and out of the various compartments. See also dehydration, water intoxication.

body f's

the fluids within the body, composed of water, electrolytes and nonelectrolytes. The volume and distribution of body fluids vary with age, sex and amount of adipose tissue. Throughout life there is a slow decline in the volume of body fluids; obesity decreases the relative amount of water in the body.

Although the body fluids are continuously in motion, moving in and out of the cells, tissue spaces and vascular system, physiologists consider them to be 'compartmentalized'. Fluid within the cell membranes is called intracellular fluid and comprises about two-thirds of the total body fluids. The remaining one-third is outside the cell and is called extracellular fluid. The extracellular fluid can be further divided into tissue fluid (interstitial fluid), which is found in the spaces between the blood vessels and surrounding cells, and intravascular fluid, which is the fluid component of blood.

The maintenance of a proper balance between the intracellular and extracellular fluid volumes is essential to health. In patients with heart failure and renal failure the balance becomes upset, producing either localized or generalized edema. Excessive fluid loss produces fluid volume deficit causing cellular dehydration and impaired cellular function.

Bouin's fluid

a histological fixative.

cerebrospinal fluid

the fluid contained within the ventricles of the brain, the subarachnoid space, and the central canal of the spinal cord. See also cerebrospinal fluid.

fluid dram

see fluid dram.

fluid extract

a liquid preparation of a vegetable drug, containing alcohol as a solvent or preservative, or both, of such strength that each milliliter contains the therapeutic constituents of 1 gram of the standard drug it represents.

fetal fluid

allantoic plus amniotic fluids.

interstitial fluid

the extracellular fluid bathing the cells in most tissues, excluding the fluid within the lymph and blood vessels.

isotonic fluid

having the same tonicity or osmotic pressure as blood.

lacrimal fluid

aqueous fluid secreted by the lacrimal glands; called also tears.

fluid line

in radiographs, the interface between fluid and gas, as in the gastrointestinal tract, will show as a straight line.

fluid loss

by vomiting, diarrhea, polyuria, water deprivation. See dehydration.

fluid mosaic model

the modern concept of the structure of a biological membrane developed by S.J. Singer and G.L. Nicolson. In it the membrane consists of protein molecules partly embedded in a discontinuous bilayer of phospholipids that form the matrix of a mosaic of functional cell units.

fluid ounce

see fluid ounce.

pericardial, pleural, peritoneal fluid

normally present in amounts sufficient only to lubricate the movement of viscera within the respective cavities. Composition similar to blood serum.

fluid replacement

see fluid therapy (below).

fluid restriction

the limitation of oral fluid intake to a prescribed amount for each 24-hour period.

fluid retention

see edema.

spinal fluid

the fluid within the spinal canal.

fluid splashing sounds

audible when gas and fluid are free in a cavity, e.g. abomasum in cases of abomasal displacement; can be elicited by shaking a small animal or part of a large animal (i.e. succussion) or by simultaneous percussion and auscultation.

synovial fluid

synovia.

fluid therapy

aims to replace fluids lost by disease process or by restriction of intake, or to maintain a high rate of fluid excretion to ensure removal of toxins, or to administer therapeutic or anesthetic agents slowly over a long period. The amounts and route of administration vary with the need of the patient. Normal solutions include 5% dextrose and Ringer's solution; alkalinizing fluids include lactated Ringer's and 1.3% sodium bicarbonate; acidifying solutions include isotonic saline and 1.9% ammonium chloride.

fluid thrill

see thrill.

fluid volume deficit

an imbalance in fluid volume in which there is loss of fluid from the body not compensated for by an adequate intake of water. The major causes are: (1) insufficient fluid intake, and (2) excessive fluid loss from vomiting, diarrhea, suctioning of gastric contents, or drainage through operative wounds, burns or fistulae. Decreased volume in the intravascular compartment is called hypovolemia. Because water moves freely between the compartments, extracellular fluid deficit causes intracellular fluid deficit (cellular dehydration), which leaves the cells without adequate water to carry on normal function.

fluid volume excess

an overabundance of water in the interstitial fluid spaces or body cavities (edema) or an excess of fluid within the blood vessels (hypervolemia) and water intoxication.

Factors that contribute to the accumulation of edematous fluid are: (1) dilatation of the arteries, as occurs in the inflammatory process; (2) reduced effective osmotic pressure, as in hypoproteinemia, lymphatic obstruction and increased capillary permeability; (3) increased venous pressure, as in congestive heart failure, thrombophlebitis and cirrhosis of the liver; and (4) retention of sodium due to increased reabsorption of sodium by the renal tubules.

fluid wave

see thrill.