Body Fluid Compartments I

These flashcards cover the key concepts related to body fluid compartments, including their measurement, distribution, and physiological significance.

What is the primary focus of this lecture on body fluid compartments?

To learn about the volume and solute content of intracellular and extracellular fluid compartments, principles for measuring them, and understanding the barriers between these compartments.

According to the lecture, what percentage of body weight (BW) is typically water in a non-obese human?

Approximately 60% of body weight.

What is the total body water volume for a standard 70 kg man as mentioned in the notes?

About 42 liters of water. (70 × 0.6)

What is the distribution of Intracellular Fluid (ICF) and Extracellular Fluid (ECF) in a typical human?

ICF is approximately 66.67% and ECF is approximately 33.33% of total body water.

What must be true for a substance (X) used to measure the volume of a fluid compartment?

It must be freely distributed throughout the entire compartment, non-toxic, not metabolized, and easily measured.

In measuring plasma volume, which dye is commonly used and why?

131 Iodine-labelled albumin or Evans Blue dye, as they bind to plasma proteins and remain within plasma.

What drives the movement of water and solutes across the capillary wall?

Chemical concentration gradients and physical pressures such as hydrostatic and colloid osmotic pressures.

What is the role of the plasma membrane in body fluid compartments?

It separates ICF and ECF and maintains differences in electrolyte concentrations through active and passive transport processes.

How is total body water calculated in an example given in the lecture?

By using the concentration of deuterium oxide (D20) in plasma, after accounting for losses, and applying it to the volume and concentration relations.

What are Starling forces and their significance in ECF?

Starling forces (hydrostatic and colloid osmotic pressures) control fluid movement across capillaries, determining filtration and reabsorption balance.