1. Nervous system:
   • Structures: Brain, spinal cord, nerves
   • Functions: Recognizes and coordinates the body’s response to changes in its internal and external environments
2. Integumentary System:
   • Structures: Skin, hair, nails, sweat and oil glands
   • Functions: Guards against infection and injury and ultraviolet radiation from the sun; helps to regulate body temperature
3. Immune/Lymphatic Systems:
   • Structures: Skeletal muscle, smooth muscle, cardiac muscle
   • Functions: Works with skeletal system to produce voluntary movement; helps to circulate blood and move food through the digestive system
4. Muscular System:
   • Structures: Skeletal muscle, smooth muscle, cardiac muscle
   • Functions: Works with skeletal system to produce voluntary movement; helps to circulate blood and move food through the digestive system
5. Circulatory System:
   • Structure: Heart, blood vessels, blood
   • Functions: Transports oxygen, nutrients, and hormones to cells; fights infection; removes cell wastes; helps to regulate body temperature
6. Skeletal System:
   • Structures: Bones, cartilage, ligaments, tendons
   • Functions: Supports the body; protects internal organs; allows movement; stores mineral reserves; contains cells that produce blood cells
7. Respiratory System:
   • Structures: Nose, pharynx, larynx, trachea, bronchi, bronchioles, lungs
   • Functions: Brings in oxygen needed for cellular respiration and removes excess carbon dioxide from the body
8. Digestive System:
   • Structures: Mouth, pharynx, esophagus, stomach, small and large intestines, rectum
   • Functions: Breaks down food; absorbs nutrients; eliminates wastes
9. Excretory System:
   • Structures: Skin, lungs, liver, kidneys, ureters, urinary bladder, urethra
   • Functions: Eliminates waste products from the body
10. Endocrine System:
    • Structures: Hypothalamus, pituitary, thyroid, parathyroids, adrenals, pancreas, ovaries (in females), testes (in males)
    • Functions: Controls growth, development, and metabolism; maintains homeostasis
11. Reproductive System:
    • Structures: Testes, epididymis, vas deferens, urethra, and penis (in males); ovaries, Fallopian tubes, uterus, vagina (in females)
    • Functions: Produces gametes; in females, nurtures and protects developing embryo