1B Flashcards
Integumentary System
System of the body compared of the skin and the underlying subcutaneous tissue.
What is the largest organ of the body?
Skin
How much of the body’s total weight does the skin compromise?
15%
Function of the Integumentary System
A. Protection of underlying (barrier to UV light, bacteria, radiation, water).
B. Acts as a site of sensory nerve receptors (pain, heat, cold, touch, pressure).
C. Regulation of body temperature (erect hairs, sweat).
D. Water excretion (sweat).
E. Formation of Vitamin D, which is essential for calcium absorption from the foods we eat.
What 2 layers is the skin composed of?
The epidermis and the dermis.
The epidermis and the dermis lie on an underlying layer called the _______.
Subcutaneous tissue
Sub=below
cutis=skin
Where is the thickest skin located?
back (1/2 cm)
Where is the thinnest skin located?
eyelid (1/2mm)
What is the outermost layer of skin?
The epidermis.
What is the epidermis composed of?
Stratified squamous keratinized epithelium.
The epidermis is avascular but does contain..
Nerve receptors and nerve endings.
The deepest layers of epidermis have cells that undergo..
Mitosis and migrate to the outermost layers, where they become desiccated, convert to keratin, and eventually slough off.
How long does it take for an epidermal cell to go from birth to slough?
30 days- thus, the epidermis (not total skin) is constantly regenerating.
What do the deepest layers of the epidermis contain?
Melanocytes that produce the dark pigment melanin.
What is melanin responsible for?
Skin color, and also protects the individual from the harmful effects of UV light.
Where is the keratin of the epidermis thick?
The palms and soles.
What does the keratin of the epidermis form?
Papillary ridges that occur in characteristic patterns (fingerprints, toe prints).
What is the layer deep to the epidermis?
The dermis.
What is the dermis composed of?
Dense irregular connective tissue, which does contain both blood vessels and nerves.