BI 211 Fluids and Electrolytes Vocabulary

Comprehensive vocabulary flashcards generated from lecture notes on fluid and electrolyte balance, capillary filtration dynamics, and clinical disorders.

Anatomic compartments

Physical spaces in the body including cavities (thoracic, abdominopelvic, cranial), lumens within organs and vessels, and joint spaces.

Functional compartments

Divisions dealing with fluid compartments and the contents dissolved within these fluids both inside and outside of cells.

Intracellular Fluid (ICF)

All fluid found within cell membranes, comprising about $65-70\%$ of total body water (about $28\,L$).

Extracellular Fluid (ECF)

All fluid found beyond cell membranes, made up of intravascular fluid and interstitial fluid (about $16\,L$).

Total body water

The overall volume of water contained within the human body, measuring about $44\,L$.

Arterial end net filtration pressure

A pressure of $+10\,mm\,Hg$ causing fluid to exit the capillary because capillary hydrostatic pressure ($35\,mm\,Hg$) exceeds blood colloidal osmotic pressure ($25\,mm\,Hg$).

Mid capillary net filtration pressure

A pressure of $0\,mm\,Hg$ resulting in no net movement of fluid because capillary hydrostatic pressure ($25\,mm\,Hg$) equals blood colloidal osmotic pressure ($25\,mm\,Hg$).

Venous end net filtration pressure

A pressure of $-7\,mm\,Hg$ causing fluid to re-enter the capillary because capillary hydrostatic pressure ($18\,mm\,Hg$) is less than blood colloidal osmotic pressure ($25\,mm\,Hg$).

Aquaporins

Protein molecules embedded in cell membranes through which water freely and rapidly moves to balance osmolarity.

Osmotic equilibrium

The state where the overall concentration of dissolved substances in the fluid inside cells is equal to that outside the cells.

Chemical disequilibrium

The condition where specific intracellular dissolved cations differ in type and concentration from major extracellular cations.

Electrical disequilibrium

The difference in charge across cell membranes where the cell interior is negative and the exterior is positive, while the overall body remains neutral.

Osmoreceptors

Sensory structures in the hypothalamus that control thirst, the primary method of fluid intake.

Volume depletion (hypovolemia)

The proportional loss of both water and sodium caused by bleeding, burns, chronic vomiting, diarrhea, or Addison's disease.

Dehydration

The loss of body water without a proportionate loss of $Na^+$, causing ECF osmolarity to rise.

Volume excess

The retention of excess water and sodium, which can be caused by kidney failure or aldosterone hypersecretion.

Hypotonic hydration

Too much retention of water combined with inadequate sodium intake, also referred to as water intoxication.

Sequestration of fluids

The abnormal accumulation of excess fluid in a specific localized space or compartment.

Edema

The sequestration of fluid specifically within the interstitial space.

Effusion

Fluid accumulation in the anatomical space between the lungs and the pleural space.

Third spacing

The movement of excessive fluid from the intravascular space (2nd space) into the interstitial space (3rd space).

Sodium ($Na^+$)

The major extracellular cation that plays the primary role in total body water balance and distribution.

Potassium ($K^+$)

The major intracellular cation and key contributor to resting membrane potentials.

Calcium ($Ca^{++}$)

A predominantly extracellular ion involved in muscle contraction, blood clotting, vessel tension regulation, neurotransmitter exocytosis, and bone structure.

Chloride ($Cl^-$)

The most abundant anion in the ECF, used to form HCl and exchanged with $HCO_3^-$ during carbon dioxide transport.

Hyperosmolality

The condition of having an abnormally high osmolality in bodily fluid.

Hyposmolality

A condition in which the blood concentrations of electrolytes, proteins, and nutrients are abnormally low.

Osmotic diuresis

A process in diabetes mellitus where high sugar concentrations in urine draw increased amounts of water into the final urine output.

Central Diabetes Insipidus

A condition where ADH production, storage, or release is abnormally low due to pressure, tumors, or injury.

Nephrogenic Diabetes Insipidus

A condition where the kidneys have an abnormally low response to ADH.

Syndrome of Inappropriate ADH (SIADH)

A disorder caused by excessive ADH production, leading to urine retention, fluid retention, concentrated urine, and hyponatremia.

Addison's Disease

A disorder of low aldosterone production that features orthostatic hypotension and hyperpigmentation caused by elevated ACTH levels.

Primary hyperparathyroidism

Excessive secretion of PTH caused by a tumor or enlarged gland, resulting in hypercalcemia, weak bones, and kidney stones.

Ascites

The shift and accumulation of fluid from blood vessels into the abdominal cavity, commonly occurring in liver cirrhosis.