Unit 3 Ultimate Study Guide

Total Body Water (TBW)

Represents the overall percentage of total body weight consisting of water, averaging between $50\%$ and $60\%$ in a healthy adult.

Intracellular Fluid (ICF)

Represents the fluid residing inside the plasma membranes of cells, accounting for approximately $\frac{2}{3}$ of total body water and roughly $40\%$ of total body weight.

Extracellular Fluid (ECF)

Represents the fluid residing outside of cell plasma membranes, accounting for approximately $\frac{1}{3}$ of total body water.

Diffusion

Solute translocation down a concentration gradient from high to low concentration.

Osmosis

Net movement of water across a semipermeable membrane toward an area of higher solute concentration.

Isotonic Solutions

Solutions that possess osmolarity equal to normal plasma, expanding extracellular volume without causing net water translocation across intracellular boundaries.

Hypotonic Solutions

Solutions that possess lower osmolarity than intracellular fluid, inducing water entry into cells and causing cellular swelling.

Hypertonic Solutions

Solutions that possess higher osmolarity than intracellular fluid, extracting water from cells and causing cellular shrinkage.

Antidiuretic Hormone (ADH)

Hormone that stimulates water reabsorption in the kidneys by promoting insertion of aquaporin water channels in collecting ducts.

Aldosterone

Hormone that stimulates renal sodium and water reabsorption while enhancing potassium excretion.

Metabolic Acidosis

Characterized by a blood pH < 7.35; caused by factors such as diabetic ketoacidosis, lactic acidosis, or severe diarrhea.

Metabolic Alkalosis

Characterized by a blood pH > 7.45; caused by factors such as protracted nasogastric suctioning or excessive ingestion of alkaline antacids.

Volume of Distribution

A pharmacokinetic parameter that quantifies the extent of drug distribution in the body.

Glomerular Filtration Rate (GFR)

The total volume of raw ultrafiltrate synthesized per minute across all nephrons in both kidneys, normally between $90\,\text{mL/min}$ and $120\,\text{mL/min}$.

Renin

An enzyme released by granular cells that initiates the renin-angiotensin-aldosterone system (RAAS) in response to low blood pressure.

Sweet Fever

A clinical term associated with elevated temperature, which can heighten insensible perspiration and physiological fluid loss.

Chloride Shift

The process of bicarbonate being exchanged for chloride ions to maintain electrical neutrality during carbon dioxide transport.