What are the four main tissue types in the human body?
Epithelial, connective, muscle, and neural tissues.
What are key characteristics of epithelial tissue?
Covers organs and body surfaces, lines cavities and hollow organs, has a free surface and basement membrane, is nonvascular, has little intercellular material, and heals rapidly.
How is epithelial tissue classified?
By number of layers (simple, stratified, pseudostratified) and cell shape (squamous, cuboidal, columnar).
Where is simple squamous epithelium found and what is its function?
Lines alveoli, capillaries, blood and lymph vessels, and body cavity membranes; functions in diffusion, filtration, and reducing friction.
What is the function of stratified squamous epithelium and where is it located?
Provides protection; found on the surface of skin, oral cavity, vagina, anal canal, and part of the pharynx.
What distinguishes keratinizing from nonkeratinizing stratified squamous epithelium?
Keratinizing epithelium has a layer of dead cells filled with keratin for waterproofing; nonkeratinizing lacks this layer and remains moist.
Where is simple cuboidal epithelium found and what are its functions?
Covers ovaries, lines kidney tubules and gland ducts; functions in absorption, secretion, and excretion.
What is the role of transitional epithelium and where is it located?
Allows distension and protection; lines urinary bladder, ureters, and part of the urethra.
What features are characteristic of simple columnar epithelium?
May have cilia for movement or microvilli for absorption, contains mucus-secreting goblet cells, and functions in secretion, absorption, and protection.
What is pseudostratified columnar epithelium and where is it found?
Appears stratified but all cells touch the basement membrane; often ciliated with goblet cells; lines respiratory passages.
What are the main types of glands based on secretion method?