Discover how many lymph nodes are in the human body (500-700 average), their key locations, why counts vary, and critical roles in cancer staging and immune function. Learn when swollen nodes need medical attention.

Understand organ system definition with our plain-English guide. Learn how 11 major body systems function, interact, and affect your health - with practical maintenance tips and myth debunking.

Discover the true length of the human small intestine (6-23 ft), how it's measured, why it varies, and its critical impact on nutrient absorption and health conditions like Short Bowel Syndrome.

Discover how many organ systems are in the human body (11 or 12?), with detailed explanations of each system's function, interactions, and why experts disagree. Includes survival rankings and clinical significance.