Biological Levels of Organizationhttp://player.discoveryeducation.com/index.cfm?guidAssetId=D601FCE2-B6F4-446E-8763-A1B9A9BA86C7

1. Cell – basic unit of structure and function Organelles – structures in the cell that perform

specific functions2. Groups of cells form tissues.3. Groups of different tissues form organs.4. Groups of different organs working together

form organ systems.5. Organ systems make up an organism.

Organization of the Human Body:

1. Body cavities2. Layers of membranes within body cavities3. Organ systems

1. Body Cavities

1. Axial portion – head, neck, and trunk2. 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

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.

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

1. Body Cavities Summary

Appendicular portion Upper limbs Lower limbs

Axial portion Dorsal cavity

Vertebral canal Cranial cavity

Oral cavity Nasal cavity Orbital cavities Middle ear cavities

1. Body Cavities Summary (cont.)

– Ventral cavity• Thoracic cavity–Mediastinum– Right lung– Left lung

• Abdominopelvic cavity– Abdominal cavity– Pelvic cavity

2. Thoracic and Abdominal Pelvic Membranes

Thoracic membranes: Walls of right and left compartments are lined

with parietal pleura (“pariet” = wall; “pleur” = rib) Lungs are covered with visceral pleura (“viscera”

= organs in a body cavity) Pleural cavity – fluid-filled “space” between the

parietal and visceral pleural membranes Heart is surrounded by pericardial membranes

(“peri” = around; “cardi” = heart) Visceral pericardium Parietal pericardium Pericardial cavity