Urine

Definition

Urine is a liquid by-product of metabolism that is excreted by the kidneys. It helps remove waste and excess substances from the body, maintaining homeostasis.

5 Must Know Facts For Your Next Test

1. Urine consists primarily of water, urea, creatinine, and various dissolved ions and organic compounds.
2. The color and concentration of urine can indicate hydration levels; dark urine usually signifies dehydration.
3. Normal urine output is about 1-2 liters per day depending on fluid intake and body needs.
4. Urine pH typically ranges from 4.6 to 8.0, reflecting the body's metabolic state and diet.
5. Certain nutrients and medications can alter the smell or color of urine; for example, asparagus can cause a distinctive odor.

Review Questions

• What are the primary components of urine?
• How does hydration status affect the color of urine?
• What is the normal daily range for urine output in adults?

Related terms

Kidneys: Organs that filter blood to produce urine, removing waste products and excess substances.

Homeostasis: The body's process of maintaining a stable internal environment despite external changes.

Metabolism: The set of life-sustaining chemical reactions in organisms that includes catabolic reactions breaking down molecules to produce energy.