1. Organism level
2. Organ System level
3. Organ level
4. Tissue Level
4.1. Muscles
4.1.1. Skeletal muscle
4.1.2. Cardiac muscle
4.1.3. Smooth muscle
4.2. Nervous
4.2.1. Neurons
4.2.1.1. Cell body
4.2.1.2. Dendrites
4.2.1.3. Axon
4.2.2. Neuroglia
4.3. Epitheal
4.3.1. Simple squamous epithelium
4.3.2. Stratified squamous epithelium
4.3.3. Simple cuboidal epithelium
4.3.4. Stratified cuboidal epithelium
4.3.4.1. Endocrine Gland
4.3.4.2. Exocrine Gland
4.3.4.2.1. Merocrine
4.3.4.2.2. Apocrine
4.3.4.2.3. Holocrine
4.3.5. Simple columnar epithelium
4.3.6. Stratified columnar epithelium
4.3.7. Pseudostratified columnar epithelium
4.4. Tissue membrane
4.4.1. Mucous membrane
4.4.2. Serous membranes
4.4.3. Cutaneous membrane
4.4.4. Synovial membrane
4.5. Connective
4.5.1. Connective tissue proper
4.5.1.1. Loose connective tissue
4.5.1.1.1. Areolar tissue
4.5.1.1.2. Adipose tissue
4.5.1.1.3. Reticular tissue
4.5.1.2. Dense connective tissue
4.5.2. Fluid connective tissue
4.5.3. Supporting connective tissue
4.5.4. Fibers