Body Fluids

These flashcards cover the essential vocabulary related to body fluids, their compartments, and regulatory mechanisms.

Body Fluids

Refers to the body water and its dissolved substances, making up approximately 60% of body weight.

Intracellular Fluid (ICF)

Fluid found inside the cells, accounting for approximately 2/3 of total body fluid.

Extracellular Fluid (ECF)

Fluid located outside of the cells, making up about 1/3 of total body fluid, which includes interstitial fluid and blood plasma.

Osmotic Pressure

The pressure required to prevent the flow of water across a semipermeable membrane; it is related to solute concentration.

Na+ - K+ pump

A membrane protein that actively transports sodium out of cells and potassium into cells, vital for maintaining ion concentration gradients.

Isotonic Solution

A solution that has the same osmotic pressure as another solution, resulting in no net movement of water across cell membranes.

Osmolality

The total concentration of solutes in a solution, which remains consistent between intracellular and extracellular fluids.

Homeostasis

The ability of the body to maintain stable internal conditions, including the regulation of body fluids.

Thirst Mechanism

Stimulated by osmoreceptors in the hypothalamus when fluid levels decrease, promoting the intake of water.

Fluid Compartments

Refers to the divisions of bodily fluid into intracellular and extracellular compartments, each with distinct functions.

Body Fluids

Refers to the body water and its dissolved substances, making up approximately 60% of body weight.

Intracellular Fluid (ICF)

Fluid found inside the cells, accounting for approximately 2/3 of total body fluid.

Extracellular Fluid (ECF)

Fluid located outside of the cells, making up about 1/3 of total body fluid, which includes interstitial fluid and blood plasma.

Osmotic Pressure

The pressure required to prevent the flow of water across a semipermeable membrane; it is related to solute concentration.

Na+ - K+ pump

A membrane protein that actively transports sodium out of cells and potassium into cells, vital for maintaining ion concentration gradients.

Isotonic Solution

A solution that has the same osmotic pressure as another solution, resulting in no net movement of water across cell membranes.

Osmolality

The total concentration of solutes in a solution, which remains consistent between intracellular and extracellular fluids.

Homeostasis

The ability of the body to maintain stable internal conditions, including the regulation of body fluids.

Thirst Mechanism

Stimulated by osmoreceptors in the hypothalamus when fluid levels decrease, promoting the intake of water.

Fluid Compartments

Refers to the divisions of bodily fluid into intracellular and extracellular compartments, each with distinct functions.

How does water move between fluid compartments?

Water moves primarily by osmosis, driven by differences in osmotic pressure and solute concentration across semipermeable membranes.

What are the primary electrolytes in Intracellular Fluid (ICF) and Extracellular Fluid (ECF)?

1. Intracellular Fluid (ICF):
   • Major cation: K^+
   • Major anions: Phosphates and proteins
2. Extracellular Fluid (ECF):
   • Major cation: Na^+
   • Major anions: Cl^-
     and bicarbonate (HCO_3^-)

What is the primary role of Antidiuretic Hormone (ADH) in maintaining fluid balance?

ADH (vasopressin) increases the permeability of the kidney collecting ducts to water, promoting water reabsorption and thereby conserving body water, which helps regulate plasma osmolality and blood volume.