Nutrition Basics: Fluid and Electrolyte Balance

These flashcards cover the fundamental concepts of fluid and electrolyte balance, including definitions of key terms, physiological regulation mechanisms, specific roles of sodium, potassium, and chloride, and the consequences of hydration imbalances as presented in the Chapter 7 lecture.

Electrolytes

Substances that, when dissolved in water, dissociate into charged ions.

Solutes

Any dissolved substances in a fluid.

Osmoregulation

The scientific term referring to the control of fluid balance and composition in the body.

Osmosis

The movement of water through a selectively permeable membrane from an area of high concentration to an area of lower concentration.

Intracellular

The compartment refers to fluid located inside of cells.

Extracellular

The compartment refers to fluid located outside of cells.

Thermoregulation

The ability of an organism to maintain body temperature despite changing environmental temperatures.

Universal solvent

A term for water because more substances dissolve in it than in any other fluid.

Adequate Intake (AI) for water (Adult Females)

$2.7\,L$ ($11$ cups) per day from all dietary sources.

Adequate Intake (AI) for water (Adult Males)

$3.7\,L$ ($15.6$ cups) per day from all dietary sources.

Thirst

An osmoregulatory mechanism triggered by decreased fluid volume or increased sodium concentration to increase water input.

Insensible water loss

Unaware water loss totaling about $400\,mL$ through exhalation and $500\,mL$ through the skin.

Sensible water loss

Aware water loss primarily through urine ($1,500\,mL$) and feces ($100\,mL$).

Renin

An enzyme secreted by the kidneys when blood volume or pressure is low to help maintain fluid balance.

Antidiuretic hormone

A hormone released by the hypothalamus that concurrently stimulates thirst and decreases urinary water loss.

Aldosterone

A hormone released by the adrenal glands to help maintain blood osmolality.

Concentration

The amount of particles in a set volume of water.

Osmotic pressure

The force exerted by solutes at different concentrations on either side of a selectively permeable membrane.

Sodium-potassium pump

The primary mechanism for cells to maintain water balance between themselves and their surrounding environment.

Hyponatremia

Low blood sodium levels characterized by nausea, muscle cramps, confusion, and dizziness.

Chloride

An electrolyte that aids in fluid balance by following sodium to maintain charge neutrality and helps maintain acid-base balance.

Cystic fibrosis

A condition caused by a mutation in a protein that transports chloride ions out of the cell, leading to salty skin and poor digestion.

Potassium

The most abundant positively charged ion inside cells, essential for nerve impulses, protein synthesis, and energy metabolism.

Hypokalemia

Low dietary intake of potassium leading to muscle weakness, cramps, and respiratory distress.

Hyperkalemia

High levels of potassium in the blood that primarily affects the heart.

Dehydration

Water loss from the body without adequate replacement, identified by symptoms like thirst, fainting, and low blood pressure.

Heat stroke

A life-threatening condition occurring when body temperature is greater than $105.1^{\circ}F$ ($40.6^{\circ}C$).

Blood pressure

The force of moving blood against arterial walls; desirable ranges are between $90/60$ and $120/80\,mmHg$.

Hypertension

Sustained high blood pressure defined as $140/90\,mmHg$ or greater.

DASH diet

An eating plan low in saturated fat and sodium that emphasizes fruits, vegetables, and low-fat dairy to reduce blood pressure.

Psychoactive drug

Any substance that crosses the blood-brain barrier and affects the brain's functioning.

Blood alcohol concentration (BAC)

A measurement of the level of alcohol in the bloodstream used to determine legal intoxication.

Alcoholic Liver Disease (ALD)

Liver problems linked to excessive alcohol intake, including fatty liver, alcoholic hepatitis, and cirrhosis.

Caffeine

A chemical derived from xanthine that acts as a psychoactive substance to increase alertness and delay fatigue.