Human Body Systems

Structure of the Body

• The human body is composed of several systems that work together to maintain homeostasis and ensure the body's overall function.
• The body is made up of:
  • Cells: the basic structural and functional units of life
  • Tissues: groups of similar cells that perform a specific function
  • Organs: structures made up of two or more types of tissues that work together to perform a specific function
  • Systems: groups of organs that work together to maintain a specific function

Body Cavities

• The body has several cavities that contain and protect internal organs:
  • Cranial cavity: contains the brain
  • Thoracic cavity: contains the heart, lungs, and major blood vessels
  • Abdominal cavity: contains the digestive organs
  • Pelvic cavity: contains the reproductive organs

Body Systems

• There are 11 major systems in the human body:
  1. Nervous system: controls and coordinates body functions
  2. Circulatory system: transports oxygen and nutrients to cells
  3. Respiratory system: brings oxygen into the body and removes carbon dioxide
  4. Digestive system: breaks down food into nutrients
  5. Endocrine system: produces hormones that regulate various body functions
  6. Immune system: protects the body against disease and infection
  7. Integumentary system: protects the body from external damage
  8. Muscular system: allows for movement and locomotion
  9. Skeletal system: provides support and protection for the body
  10. Urinary system: removes waste and excess fluids from the body
  11. Reproductive system: produces sex cells and supports the development of a fetus during pregnancy