Chapter 5: The Integumentary System Flashcards
cutaneous membrane
another name for skin
functions of the integumentary system
- Regulates body temperature.
- Stores blood.
- Protects body from external environment.
- Detects cutaneous sensations.
- Excretes and absorbs substances.
- Synthesizes vitamin D.
components of the integumentary system
- epidermis
- dermis
- subcutaneous layer
- hairs
- nails
- glands
epidermis is composed of
keratinized stratified squamous epithelium
keratinocytes
- 90% of epidermal cells
- produce keratin
- produce lamellar granules
keratin
- tough,
- fibrous
- intracellular protein that helps protect the skin and underlying tissues from abrasions, heat, microbes, and chemicals
lamellar granules
- release a water‐repellent sealant
- decreases water entry and water loss and inhibits the passage of foreign materials
melanocytes
-produce the pigment melanin
melanin
- yellow‐red or brown‐black pigment
- contributes to skin color
- absorbs damaging ultraviolet (UV) light
UV protection
- Once inside keratinocytes, the melanin granules cluster to form a protective veil over the nucleus,
- on the side toward the skin surface. In this way, they shield the nuclear DNA from damage by UV light.
- Although their melanin granules effectively protect keratinocytes, melanocytes themselves are particularly susceptible to damage by UV light.
Langerhans cell
Epidermal dendritic cell that functions as an antigen‐presenting cell (APC) during an immune response. Also called an intraepidermal macrophage.
Merkel cell
Type of cell in the epidermis of hairless skin that makes contact with a tactile (Merkel) disc, which functions in touch. Also called a tactile epithelial cell.
the five layers of the strratum
- basale
- spinosum
- granulosum
- lucidum
- corneum
basale
deepest layer
-composed of a single row of cuboidal or columnar keratinocytes
Stratum Granulosum
consists of three to five layers of flattened keratinocytes that are undergoing apoptosis
- water proofing
- last layer of O2, too far
Stratum Spinosum
numerous keratinocytes produced by the stem cells in the basal layer, arranged in 8–10 layers
Stratum Lucidum
present in the thick skin of areas such as the fingertips, palms, and soles
four to six layers of clear, flat, dead keratinocytes that contain large amounts of keratin and thickened plasma membranes
-thick dead skin
Stratum Corneum
consists on average of 25 to 30 layers of flattened dead keratinocytes
dermis
A layer of dense irregular connective tissue lying deep to the epidermis.
region of the skin that leather is made from
dermis