{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Epidermis - Epidermis outermost superficial region Dermis...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Epidermis- outermost superficial region Dermis- middle region Hypodermis- (superficial fascia) – deepest region Epidermis Composed of keratinized stratified squamous epithelium consisting of four distinct cell types and four or five layers Cell types include keratinocytes, melanocytes, merkel cells and langerhans cells Outer portion of the skin is exposed to the external environment and functions in protection. Cells of the Epidermis Keratinocytes – produce the fibrous protein keratin Melanocytes – produce the brown pigment melanin Langerhans cells – epidermal macrophages that help activate the immune system Merkel cells – function as tough, receptors in association with sensory nerve endings. Layers of the Epidermis: Stratum Basal Deepset epidermal layer firmly attached to the dermis Consists of a single row of the youngest keratinocytes Cells undergo rapid division Stratum Spinosum (prickly) Cells contain a weblike system of intermediate filametnts attached to desmosomes Melanin granules and Langerhans cells are abundant in this layer Stratum Granulosum Thin; three to five cell layers in which drastic changes in keratinocyte appearance occurs Stratum Lucidum Thin, transparent band superficial to the stratum granulosum Consists of a few rows of flat dead keratinocytes Present only in thick skin Stratum Corneum Outermost layer of keratinized cells Accounts for .75 of the epidermis thickness Functions include: Waterproofing, protection from abrasion and penetration, physical barrier rendering the body relatively insensitive to biological, chemical, and physical assaults. Dermis Second major skin region containing strong, flexible connective tissue Cell types include fibroblasts, macrophages, and occasionally mast cells and white blood cells Composed of two layers- papillary and reticular Papillary layer Areolar connective tissue with collagen and elastic fibers Its superior surface contains peglike projections called dermal papillae
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}