1. Biological Levels of Organization
Cell – basic unit of structure and function
Organelles – structures in the cell that perform specific functions
Groups of cells form tissues.
Groups of different tissues form organs.
Groups of different organs working together form organ systems.
Organ systems make up an organism.
Show UnitedStreaming video clip.

2. Organization of the Human Body:
Body cavities
Layers of membranes within body cavities
Organ systems

3. 1. Body Cavities Axial portion – head, neck, and trunk
Appendicular portion – upper and lower limbs (“append” = to hang)
Axial portion:
Dorsal cavity (“dors” = back)
Ventral cavity
Dorsal cavity:
Cranial cavity (“cran” = helmet)
Vertebral canal

4. 1. Body Cavities (cont.) Ventral cavity: Thoracic cavity:
Abdominopelvic cavity
Thoracic cavity:
Thoracic and abdominopelvic cavities are separated by the diaphragm.
Mediastinum
A region that separates the thoracic cavity into 2 compartments containing the right and left lungs
All other thoracic viscera (organs) are in the mediastinum.

5. 1. Body Cavities (cont.) Abdominopelvic cavity:
Abdominal cavity – contains stomach, spleen, liver, gallbladder, kidneys, and most of the small and large intestines
Pelvic cavity (“pelv” = basin) – contains the terminal portion of the large intestine, urinary bladder, and internal reproductive organs.
Smaller cavities in the head:
Oral cavity
Nasal cavity
Orbital cavities
Middle ear cavities
Hand out blank outline forms of the body cavities for the students to complete. Teaches organization of the body cavities. (Answers on the next 2 slides)

6. 1. Body Cavities Summary Appendicular portion Axial portion
Upper limbs
Lower limbs
Axial portion
Dorsal cavity
Vertebral canal
Cranial cavity
Oral cavity
Nasal cavity
Orbital cavities
Middle ear cavities

7. 1. Body Cavities Summary (cont.)
Ventral cavity
Thoracic cavity
Mediastinum
Right lung
Left lung
Abdominopelvic cavity
Abdominal cavity
Pelvic cavity