Biology 1201A Lecture Notes - Lecture 43: Stratum Granulosum, Cytokeratin, Stratum Corneum
Document Summary
Cartilage: cartilage is, at the most basic level, an extracellular connective tissue found throughout the body. Bone grows in three stages: first, tissue forms a mesh of collagen fibers, then the body creates a polysaccharide that acts like cement to hold the tissues together. Finally, calcium crystals salts are deposited to form bone. The integumentary system comprises the skin and appendages. The appendages include nails, hair, and sweat glands. The skin is the largest organ of your body, weighing approximately 21 pounds. There are three distinct layers to the skin. In order from outermost to innermost, the order is: epidermis, dermis, and hypodermis (subcutaneous tissue). The epidermis is composed of five strata (latyers). The stratum basale is the most inferior strata of the epidermis and is composed of keratinocytes, which secrete cytokeratin, giving skin its toughness to protect skin. The stratum basale also is known for rapid cell division, and where we get our skin color.