BLG 10A/B Lecture Notes - Lecture 5: Epithelium, Apoptosis, Root Hair
21 Apr 2020
School
Department
Course
Professor
Document Summary
Integumentary system consists of: skin, hair, nails, sweat glands, sebaceous (oil) glands. Skin consists of two distinct regions: epidermis: superficial region, consists of epithelial tissue and is avascular, dermis: underlies epidermis. Cells of the epidermis: epidermis consists mostly of keratinized stratified squamous epithelium, producing keratin protein, four cell types found in epidermis: Dendritic (langerhans) cells: star-shaped macrophages that patrol deep epidermis, are key activators of immune system. Tactile (merkel) cells: sensory receptors that sense touch. Layer of the epidermis: epidermis is made up of four or five distinct layers. Thick skin contains five layers (strata) and is found in high-abrasion areas (hands, feet) Several cell layers thick: cells contain weblike system of intermediate prekeratin filaments attached to desmosomes, allows them to resist tension and pulling, keratinocytes in this layer appear spikey, so they are called prickle cells. Scattered among keratinocytes are abundant melanosomes and dendritic cells.
