Nutrition, Hydration & Homeostasis

Comprehensive vocabulary flashcards covering nutrition principles, modified diets, enteral and parenteral feeding, fluid compartments, electrolyte imbalances, acid-base homeostasis, and intravenous therapy from Wilkinson's Fundamentals of Nursing.

Metabolism

The body's chemical conversion and use of nutrients, comprising anabolism (building larger molecules) and catabolism (breaking molecules down and releasing energy).

Dietary Reference Intakes (DRIs)

A comprehensive set of reference values that guide nutrient intake for healthy populations, encompassing EAR, RDA, AI, UL, and AMDR.

Macronutrient

Nutrients required in large amounts that supply caloric energy to the body: carbohydrates ($4\,\text{kcal/g}$), proteins ($4\,\text{kcal/g}$), and fats ($9\,\text{kcal/g}$).

Micronutrient

Essential dietary elements needed in smaller amounts—namely vitamins and minerals—that do not supply energy directly but support metabolism and physiological function.

Dietary Fiber

A complex polysaccharide carbohydrate that is not digested into usable glucose and functions primarily to support healthy bowel elimination and motility.

Glycogen

The stored form of carbohydrate held in the liver and muscle tissue used to supply short-term energy needs.

Essential Amino Acid

An amino acid that cannot be synthesized by the body in sufficient quantities and must be supplied directly through the diet.

Complete Protein

A dietary protein source containing all of the essential amino acids required for tissue building and maintenance.

Negative Nitrogen Balance

A state in which nitrogen excretion exceeds nitrogen intake, indicating tissue protein breakdown commonly precipitated by illness, trauma, burns, or malnutrition.

Triglyceride

The primary form of dietary lipid and the principal storage form of fat in the body.

Sterol

A category of lipids that includes cholesterol, serving as structural components of cell membranes and precursors to steroid hormones.

Phospholipid

A class of lipids that form major structural components of cell membranes and lipoproteins.

Low-Density Lipoprotein (LDL)

A lipoprotein that transports cholesterol from the liver to peripheral body tissues; elevated levels are associated with increased cardiovascular risk.

High-Density Lipoprotein (HDL)

A lipoprotein that transports excess cholesterol from body tissues back to the liver for excretion or recycling, providing a protective cardiovascular effect.

Fat-Soluble Vitamins

Vitamins A, D, E, and K, which are stored in the body's fatty tissue and liver; because they are stored, excessive intake increases the risk of toxicity.

Water-Soluble Vitamins

Vitamins including the B-complex group and Vitamin C, which require regular dietary intake because excess amounts are readily excreted in the urine.

Basal Metabolic Rate (BMR)

The rate at which energy is expended at rest to maintain vital physiological functions, influenced by lean body mass, age, temperature, growth, disease, and activity.

Body Mass Index (BMI)

An anthropometric screening tool assessing weight relative to height; categories include underweight ($<18.5$), healthy ($18.5\text{--}24.9$), overweight ($25\text{--}29.9$), and obese ($\ge 30$).

NPO

A medical order meaning "nil per os" (nothing by mouth), restricting all oral food and fluid intake commonly before procedures or in patients with acute aspiration risk.

Clear Liquid Diet

A short-term, nutritionally incomplete therapeutic diet consisting of transparent liquids such as broth, gelatin, apple juice, cranberry juice, tea, and popsicles.

Full Liquid Diet

A therapeutic diet comprising all clear liquids plus fluids and foods that turn liquid at room temperature, including milk, puddings, custards, yogurt, and cream soups.

Mechanical Soft Diet

A diet modified in texture for patients with chewing or swallowing limitations, including ground or finely chopped tender meats, soft-cooked vegetables, and soft breads.

Pureed Diet

A modified diet consisting of foods processed or blenderized to a smooth, cohesive consistency without distinct lumps for patients with significant dysphagia.

Dysphagia

Difficulty swallowing, signaled clinically by coughing or choking during intake, a wet or gurgly vocal quality, food pocketing, or recurrent pneumonia.

Enteral Nutrition

The delivery of liquid formula nutrients directly into the functioning gastrointestinal tract via a tube when oral intake is impossible or inadequate.

Parenteral Nutrition (PN)

The administration of a hypertonic intravenous nutritional solution containing glucose, amino acids, electrolytes, vitamins, and minerals to patients unable to absorb nutrients via the GI tract.

Intracellular Fluid (ICF)

Fluid contained within cell membranes, accounting for approximately $40\%$ of total adult body weight.

Extracellular Fluid (ECF)

Fluid located outside cells, comprising intravascular fluid (plasma), interstitial fluid between tissue cells, and transcellular fluids.

Third Spacing

The abnormal shift of fluid into a body compartment where it is physiologically unavailable (e.g., ascites, burn blisters, pleural effusion), causing intravascular depletion despite edema.

Osmosis

The passive movement of water molecules across a semipermeable membrane from an area of lower solute concentration toward an area of higher solute concentration.

Diffusion

The passive movement of solute particles through a solution from an area of higher concentration to an area of lower concentration.

Filtration

The movement of water and dissolved solutes across a membrane from an area of higher hydrostatic pressure to an area of lower hydrostatic pressure.

Active Transport

The movement of solutes across a cell membrane against a concentration gradient, requiring metabolic energy in the form of $\text{ATP}$ (e.g., the sodium-potassium pump).

Isotonic Solution

An intravenous solution having an osmolality equivalent to normal blood serum (e.g., $0.9\%\,\text{NaCl}$, Lactated Ringer's), remaining primarily within the intravascular space.

Hypotonic Solution

An intravenous solution with an osmolality lower than blood serum (e.g., $0.45\%\,\text{NaCl}$), causing water to move out of the vascular space into cells and interstitial spaces.

Hypertonic Solution

An intravenous solution with an osmolality higher than blood serum, causing fluid to shift by osmosis from intracellular and interstitial spaces into the intravascular space.

Antidiuretic Hormone (ADH)

A hormone released by the pituitary gland in response to high blood osmolality or low vascular volume that directs the renal tubules to reabsorb water.

Renin-Angiotensin-Aldosterone System (RAAS)

A neurohormonal compensatory pathway where renin release leads to angiotensin II generation, triggering aldosterone secretion to retain sodium and water while excreting potassium.

Sodium ($\text{Na}^+$)

The primary extracellular cation (normal reference range: $135\text{--}145\,\text{mEq/L}$) responsible for regulating fluid distribution, plasma osmolality, and nerve/muscle conduction.

Potassium ($\text{K}^+$)

The major intracellular cation (normal reference range: $3.5\text{--}5.3\,\text{mEq/L}$) essential for cardiac electrical conduction, heart rhythm stability, and skeletal muscle action.

Calcium ($\text{Ca}^{2+}$)

A crucial mineral (normal reference range: $8.5\text{--}10.5\,\text{mg/dL}$) required for bone and tooth integrity, blood coagulation, neuromuscular transmission, and cardiac muscle contraction.

Magnesium ($\text{Mg}^{2+}$)

A vital intracellular electrolyte (normal reference range: $1.6\text{--}2.6\,\text{mEq/L}$) that acts as an enzyme cofactor and regulates neuromuscular and cardiac electrical irritability.

Chloride ($\text{Cl}^-$)

The primary extracellular anion (normal reference range: $95\text{--}105\,\text{mEq/L}$) that works alongside sodium to maintain osmotic pressure and acid–base balance.

Phosphate ($\text{PO}_4^{3-}$)

The primary intracellular anion (normal reference range: $2.5\text{--}4.5\,\text{mg/dL}$) essential for cellular energy production ($\text{ATP}$), chemical buffering, and bone mineral structure.

Bicarbonate ($\text{HCO}_3^-$)

A major chemical buffer (normal reference range: $22\text{--}26\,\text{mEq/L}$) regulated by the kidneys to preserve systemic acid–base equilibrium.

Hypovolemia

An abnormal deficit in intravascular extracellular fluid volume resulting from inadequate intake, excessive fluid loss, or fluid shifting, presenting with tachycardia, weak pulses, and hypotension.

Hypervolemia

An abnormal excess of fluid in the vascular and extracellular spaces, marked by rapid weight gain, peripheral edema, jugular venous distention, bounding pulses, and dyspnea.

Acidosis

A systemic physiological state characterized by an arterial blood pH falling below $7.35$, driven by either respiratory carbon dioxide accumulation or metabolic base deficits.

Alkalosis

A systemic physiological state characterized by an arterial blood pH rising above $7.45$, driven by either respiratory carbon dioxide depletion or metabolic bicarbonate excess.

Infiltration

The leakage of a non-vesicant intravenous fluid into the surrounding subcutaneous tissue, characterized by skin pallor, swelling, coolness, and reduced infusion rate.

Extravasation

The inadvertent escape of a vesicant or tissue-damaging intravenous medication into perivascular tissues, causing localized pain, burning, tissue ischemia, or necrosis.

Phlebitis

Inflammation of a vein related to chemical, mechanical, or bacterial irritation from an IV catheter, manifesting as erythema, warmth, pain, and a palpable venous cord.

Peripherally Inserted Central Catheter (PICC)

A long, flexible venous catheter inserted into a peripheral vein whose tip terminates within the superior vena cava, suitable for intermediate-to-long-term IV therapy.

IV Drop Rate Formula

The mathematical equation used to determine gravity infusion rates: $\text{Hourly rate (mL/hr)} \times \text{drop factor (gtt/mL)} \div 60 = \text{gtt/min}$.