1. Integumentary System: This system protects the body from external threats, aids in sensing the environment, and helps regulate body temperature. It includes the skin, hair, nails, and sweat glands.
2. Skeletal System: The skeletal system provides the body with shape and support, facilitates movement, protects vital organs, and produces red blood cells in bone marrow. It includes bones, joints, and cartilage.
3. Muscular System: This system allows for movement, maintains posture, and generates heat to help regulate body temperature. It consists of skeletal muscle, smooth muscle, and cardiac muscle.
4. Nervous System: The nervous system controls all body functions, receives and processes information, and coordinates responses to various stimuli. It includes the brain, spinal cord, nerves, and sensory organs.
5. Endocrine System: The endocrine system regulates various bodily functions through hormone production. It includes endocrine glands, such as the thyroid, pituitary, and adrenal glands.
6. Cardiovascular System: This system transports blood, nutrients, and oxygen throughout the body and carries away waste products. It includes the heart, blood vessels (arteries, veins, and capillaries), and blood.
7. Respiratory System: The respiratory system facilitates gas exchange, allowing for the intake of oxygen and the release of carbon dioxide. It includes the lungs, bronchial tubes, and nasal passages.
8. Digestive System: The digestive system breaks down food into nutrients that the body can absorb and use for energy. It consists of the mouth, esophagus, stomach, intestines, liver, and pancreas.
9. Urinary System: This system filters waste products from the blood, produces urine, and maintains fluid balance. It includes the kidneys, ureters, bladder, and urethra.
10. Reproductive System: The reproductive system allows for the procreation of new individuals and the continuation of the species. It differs between males and females, with specialized organs and structures for each gender.
11. Lymphatic System: The lymphatic system helps defend the body against infections and plays a role in fluid balance. It consists of lymph vessels, lymph nodes, and lymphoid organs like the spleen and thymus.
