LO1: Fluid Compartments and Solutes

Flashcards about fluid compartments, solutes, and osmolarity in body fluids.

What is total body water (TBW)?

TBW is the total amount of water in the body, accounting for 55–60% of adult body mass.

What are the two main fluid compartments of the body?

Extracellular Fluid (ECF) and Intracellular Fluid (ICF).

What is extracellular fluid (ECF)?

Fluid found outside of body cells; it includes plasma and interstitial fluid.

What is intracellular fluid (ICF)?

The fluid (cytoplasm) inside cells, making up about 66% of body water.

What percentage of body water does the ICF make up?

About two-thirds (66%) of total body water.

What percentage of body water does the ECF make up?

About one-third (33%) of total body water.

What are the two main subcompartments of the ECF?

Interstitial fluid and plasma.

What is interstitial fluid?

Fluid found in the spaces between cells, mostly in connective tissues; it makes up 4/5 of the ECF.

What is plasma?

The fluid portion of blood, making up 1/5 of the ECF.

What are solutes?

Substances dissolved in body fluids (e.g., ions, sugars, amino acids).

What are electrolytes?

Charged solutes (ions) that conduct electricity in water.

What are non-electrolytes?

Uncharged solutes that do not conduct electricity in water.

List examples of electrolytes found in body fluids.

Sodium (Na), Potassium (K), Calcium (Ca²), Chloride (Cl), Acids (H), and Bases (OH).

List examples of non-electrolytes found in body fluids.

Glucose, amino acids, and fatty acids.

Is osmolarity equal between the ECF and ICF?

Yes, the osmolarity is equal, meaning total solute concentration is balanced across compartments.

Which type of solute contributes most to osmolarity?

Electrolytes (because of their ionic charge and water-attracting ability).

Why is osmolarity important in fluid compartments?

It helps determine water movement between compartments, maintaining cell shape and function.

Which solute is most abundant in the ECF?

Sodium (Na).

Which solute is most abundant in the ICF?

Potassium (K).

Where is chloride (Cl) mainly found?

In the ECF.

Where are amino acids primarily found?

In the ICF.