The study of Tissue 

~200 cell types

• Provides protection
• Secretion 
• Absorption
• Made up of a massive number of cells
• Avascularity
• High regeneration ability 

• Single Layer
• Flat
• Makes substances pass easily 

• Single Layer
• More height 
• Nucleus is more round 
• More absorption, secretion, and protection

• Single Layer
• Tall
• Goblet cells
• Microvilli
• High secretion and absorption

• One Layer 
• Tall
• Cilla 
• Goblet cells
• not every cell reaches the apical surface
• Barrier: prevents infection and tissue injury
• Moves stuff across surface

• Many Layers
• Keratin
• Cells at the basement membrane go through mitosis
• Old cells get pushed up to the surface
• Prevents dehydration, abrasion, and Infection
• Protective Barrier

• Many Layers 
• Thinner and delicate 
• In areas prone to dryness
• Moves things across 
• No surface layer of dead cells
• Makes secretions and provides protection

• Many tissues 
• Allows stretch 
• Allows tissue to contract and expand

• Increases surface area
• More absorbing and releasing

• Tight
• Gap
• Desmosomes
• Hemidesmosomes

• Ectoderm
• Mesoderm
• Endoderm

• Epithelial
• Connective
• Muscle
• Nervous