Water, Electrolytes, and Hydration Mechanics

Vocabulary flashcards covering cellular membrane transport, fluid balance, water distribution, electrolytes, and related physiological conditions based on lecture transcripts.

Dipole

A property of a water molecule where the hydrogen end carries a partial positive charge and the oxygen end carries a partial negative charge due to oxygen's higher electronegativity.

Hydrogen bond

The electrostatic attraction between the slightly positive hydrogen atom of one water molecule and the slightly negative oxygen atom of another water molecule.

Intracellular fluid (ICF)

The fluid located inside cells, which accounts for approximately two-thirds of total body water or $40\%$ of total body weight.

Extracellular fluid (ECF)

The fluid located outside of cells, including blood plasma and interstitial fluid between cells, making up approximately one-third of total body water or $20\%$ of total body weight.

Electrolytes

Electrically charged mineral molecules or ions dissolved in body water that dissociate into positively charged cations or negatively charged anions.

Osmosis

The passive movement of water across a selectively permeable membrane from an area of low solute concentration to an area of high solute concentration.

Blood osmolarity

The overall concentration of all substances dissolved in the blood, normally around $300\,\text{mOsm/L}$, which serves as a measure of hydration status.

Insensible water loss

Unnoticed fluid loss from the body occurring continuously through exhalation ($400\,\text{mL/day}$) and evaporation through the skin ($500\,\text{mL/day}$), totaling $600$ to $900\,\text{mL/day}$.

Sensible water loss

Noticeable fluid loss from the body, primarily consisting of urine output (approximately $1,500\,\text{mL/day}$) and feces (approximately $100\,\text{mL/day}$).

Sodium-potassium pump

An active transport membrane protein that uses energy from ATP to transfer $3$ sodium ions out of a cell in exchange for $2$ potassium ions into the cell against their concentration gradients.

Resting membrane potential

The electrical voltage difference across a cell membrane at rest, where the inside of the cell is generally more negative than the outside.

Potassium leakage channels

Protein channels in the cell membrane that allow positive potassium ions to passively diffuse out of the cell down their chemical gradient, majorly contributing to the negative charge inside a resting cell.

Electrochemical gradient

A dual gradient across a membrane created by differences in both electrical charge (voltage) and specific chemical ion concentrations.

Hypotonic solution

A solution containing a lower concentration of dissolved particles than the inside of a cell, causing water to enter the cell and make it swell or expand.

Hypertonic solution

A solution containing a higher concentration of dissolved particles than the inside of a cell, causing water to move out of the cell and make it shrink or appear spiky.

Isotonic solution

A solution containing an equal concentration of dissolved particles on both sides of a membrane, resulting in no net movement of water and maintaining normal cell shape.

Osmotic pressure

The force exerted by dissolved solutes at higher concentrations on one side of a selectively permeable membrane, pulling water toward the region of higher solute concentration.

Glucose symporter

A transport protein that harnesses the sodium concentration gradient established by the sodium-potassium pump to power the co-transport of glucose into the cell.

Hyponatremia

A condition characterized by low blood sodium levels, often caused by excessive plain water consumption or fluid loss, leading to cellular swelling, nausea, cramps, confusion, coma, or death.

DASH diet

Dietary Approaches to Stop Hypertension; an eating plan high in potassium, calcium, and magnesium, and low in saturated fat and sodium, designed to lower blood pressure.

Salt sensitivity

A condition affecting $10\%$ to $20\%$ of the population where an individual's blood pressure directly increases or decreases in response to dietary sodium intake.

Cystic fibrosis

An inherited genetic disorder caused by a mutation in a protein that transports chloride ions out of cells, leading to salty skin, sticky mucus accumulation in lungs, and poor digestion.

Bioavailability

The proportion of a specific nutrient in food that is absorbed in the intestine and available to perform its intended biological functions in the body.

Hypokalemia

Abnormally low blood potassium levels resulting from inadequate intake or diuretic usage, leading to muscle weakness, cramps, respiratory distress, constipation, and cardiac arrhythmias.

Hyperkalemia

Abnormally high levels of potassium in the blood, usually caused by kidney dysfunction, which disrupts electrical impulses in the heart and can lead to cardiac arrest.

Heat stroke

A life-threatening medical condition defined by a body temperature exceeding $104\,^\circ\text{F}$, caused by thermoregulatory failure and impaired sweating due to severe fluid depletion.

Hypertension

A condition defined as a sustained arterial blood pressure reading of $130/80\,\text{mmHg}$ or higher, which increases the risk for cardiovascular disease, heart attack, and stroke.

Caffeine

A xanthine compound found in plants that acts as an unregulated psychoactive drug by blocking adenosine receptors in the brain to increase alertness and delay fatigue.

Aldosterone

A hormone secreted by the adrenal glands in response to low blood sodium or high blood potassium that stimulates the kidneys to reabsorb sodium and water while excreting potassium.

Antidiuretic hormone (ADH)

A hormone released by the pituitary gland via hypothalamic signaling in response to low blood volume or high blood osmolality to reduce water excretion in urine.