Skip to content - Cardiovascular system The heart and blood vessels that circulate blood, delivering oxygen and nutrients and carrying hormones and immune cells throughout the body. 🧬 5 ⚡ 59
- Digestive system The gut and accessory organs that break down food, absorb nutrients, and host the microbiome — a major endocrine and immune interface (the gut–brain axis). 🧬 6 ⚡ 56
- Endocrine system The network of glands that produce hormones — the body’s slow, wide-reaching chemical signaling system regulating metabolism, growth, mood, and reproduction. 🧬 14 ⚡ 58
- Immune system The cells, tissues, and signaling that defend against pathogens and regulate inflammation — strongly modulated by stress hormones, sleep, and nutrition. 🧬 1 ⚡ 28
- Integumentary system Skin, hair, and nails — the body’s barrier and largest organ, involved in temperature regulation, vitamin D synthesis, and sensation. 🧬 3 ⚡ 25
- Lymphatic system The vessels and nodes that drain tissue fluid, transport immune cells, and absorb dietary fats — closely tied to the immune system. 🧬 0 ⚡ 3
- Musculoskeletal system Muscles, bones, and connective tissue that provide movement, support, and mineral storage — highly responsive to loading, sex hormones, and growth hormone. 🧬 8 ⚡ 52
- Nervous system The brain, spinal cord, and nerves that sense, integrate, and command the body — the fast electrical/chemical signaling counterpart to the endocrine system. 🧬 10 ⚡ 60
- Reproductive system The organs and hormones governing sexual development, fertility, and reproduction, with wide secondary effects on bone, mood, and metabolism. 🧬 4 ⚡ 10
- Respiratory system The airways and lungs that exchange oxygen and carbon dioxide — the rate and depth of breathing are tightly coupled to autonomic tone and stress. 🧬 1 ⚡ 17
- Urinary system The kidneys and urinary tract that filter blood, balance fluids and electrolytes, and regulate blood pressure and red-blood-cell production. 🧬 1 ⚡ 14