• An Organ is formed by the combination of several (usually all four) tissues integrated to perform a specific function. Each organ is usually characterized by one or more specific primary tissues, the others being secondary or general. A group of organs that perform similar functions constitute a system. Listed below are examples of 5 universal (present throughout the body) organs:

1. Skin

A. Primary Tissues

1. epidermis (stratified squamous epithelium)

2. dermis (dense irregular CT)

B. Secondary Tissues

1. arrector pili muscles (smooth muscle)

2. sensory and autonomic nerves

2. Bone (e.g. humerus)

A. Primary Tissue = connective tissue

B. Secondary Tissues

1. epithelium and smooth muscle in blood vessels

2. nerves to blood vessels (autonomics) and periosteum (sensory)

3. Muscle (e.g. biceps brachii)

A. Primary Tissue = skeletal muscle

B. Secondary Tissues

1. CT (e.g. epimysium)

2. epithelium in blood vessels

3. motor nerves

4. Artery (e.g. brachial)

A. Primary Tissues

1. tunica intima (simple squamous epithelium)

2. tunica media (smooth muscle)

B. Secondary Tissues

1. tunica adventitia (loose CT)

2. autonomic nerves

5. Nerve (e.g. musculocutaneous)

A. Primary Tissue = nervous

B. Secondary Tissues

1. epineurium (CT)

2. epithelium and smooth muscle in blood vessels

• A System is formed by the combination of several organs integrated to perform a related set of functions. An Organism is the product of a collected set of systems. The 10 basic systems are the:

1. Integumentary

2. Skeletal

3. Muscular

4. Nervous

5. Cardiovascular

6. Respiratory

7. Digestive

8. Urinary

9. Reproductive

10. Endocrine

• The first five of these systems are said to be universal in that they are present in all regions of the body.





• The human (mammalian) body may be somewhat arbitrarily subdivided into 8 regions:

1. Head

2. Neck

3. Back

4. Thorax

5. Abdomen

6. Pelvis

7. Pectoral Limb

8. Pelvic Limb