Location: Nonciliated type in male’s sperm-carrying ducts and ducts of large glands; ciliated variety lines the trachea, most of the upper respiratory tract. Photomicrograph: Pseudostratified ciliated columnar epithelium lining the human trachea (570x). Trachea Cilia Pseudo- stratified epithelial layer Basement membrane Mucus of mucous cell
Figure 4.3e Epithelial tissues. (e) Stratified squamous epithelium Description: Thick membrane composed of several cell layers; basal cells are cuboidal or columnar and metabolically active; surface cells are flattened (squamous); in the keratinized type, the surface cells are full of keratin and dead; basal cells are active in mitosis and produce the cells of the more superficial layers. Function: Protects underlying tissues in areas subjected to abrasion. Location: Nonkeratinized type forms the moist linings of the esophagus, mouth, and vagina; keratinized variety forms the epidermis of the skin, a dry membrane. Photomicrograph: Stratified squamous epithelium lining the esophagus (285x). Stratified squamous epithelium Nuclei Basement membrane Connective tissue
Figure 4.3f Epithelial tissues. (f) Transitional epithelium Description: Resembles both stratified squamous and stratified cuboidal; basal cells cuboidal or columnar; surface cells dome shaped or squamouslike, depending on degree of organ stretch. Function: Stretches readily and permits distension of urinary organ by contained urine. Location: Lines the ureters, urinary bladder, and part of the urethra. Photomicrograph: Transitional epithelium lining the urinary bladder, relaxed state (360X); note the bulbous, or rounded, appearance of the cells at the surface; these cells flatten and become elongated when the bladder is filled with urine.
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- Fall '16
- Dr. Faiz Salehi
- Anatomy, Epithelial tissue, squamous epithelial tissue, columnar epithelial tissue