• Objectives and Review
• Pre-Lab Quiz
• Pre-Lab Reporting
• Data Collection
• Data Analysis
• Laboratory Report

Synopsis of Experiment

Healthy, normally hydrated 25-28 year old males are asked to refrain from alcohol or caffeine-containing beverages and to avoid physical exercise a day before beginning each of three hydration states. These states are:

• Normal hydration -normal fluid intake for 12 hours, no fluid at start of experiment
• Dehydration - deprived of water for 12 hours, no fluid at start of experiment
• Water loaded - normal fluid intake for 12 hours, then at start of experiment, subjects given 1500 mL of distilled water to drink within 5 minutes.

Subjects will void immediately before the start of the experiment. After 30 minutes, the subjects will void again, and the urine output will be measured at a room temperature of 20°C (68°F). Blood samples will be collected. Urine and plasma will be monitored for osmolarity which is measured using freezing point depression.

Subjects' urine volume and urine and blood plasma osmolarity will be measured and compared for normal hydration, dehydration, and excessive hydration.

Predictions

Based on what you know, predict the outcome of each experiment. Complete the numbered statements below by choosing one response for each number.

When you are done, click the Submit button to save your responses to the laboratory report.

Congratulations

Variables

Now determine the dependent, independent, and controlled variables for each experiment in this laboratory activity by clicking on the appropriate answers.

Check your answers until you have chosen all variables correctly. There will be one choice for Dependent and Independent Variables and multiple choices for Controlled Variables. When you are done, click the Submit button to save your responses to the laboratory report.