Integumentary System Flashcards
Integumentary System
Encloses internal body structures; site of many sensory receptors; thermoregulation; vitamin D synthesis
Function #1 - Protection
The skin protects the rest of the body from the basic elements of nature such as wind, water, and UV sunlight.
Sensory Function
The fact that you can feel an ant crawling on your skin, allowing you to flick it off before it bites, is because the skin, and especially the hairs projecting from hair follicles in the skin, can sense changes in the environment.
Thermoregulation
The integumentary system helps regulate body temperature through its tight association with the sympathetic nervous system, the division of the nervous system involved in our fight-or-flight responses
Vitamin D Synthesis
The epidermal layer of human skin synthesizes vitamin D when exposed to UV radiation. In the presence of sunlight, a form of vitamin D3 called cholecalciferol is synthesized in the skin. Vitamin D is essential for normal absorption of calcium and phosphorous, which are required for healthy bones.
Skin
The skin is made of multiple layers of cells and tissues, which are held to underlying structures by connective tissue. The deeper layer of skin is well vascularized (has numerous blood vessels). It also has numerous sensory, and autonomic and sympathetic nerve fibers ensuring communication to and from the brain.
Keratinocyte
The keratinocytes in the stratum corneum are dead and regularly slough away, being replaced by cells from the deeper layers
Keratin
is an intracellular fibrous protein that gives hair, nails, and skin their hardness and water-resistant properties.
Stratum basale
Deepest epidermal layer (the base) and attaches the epidermis to the basal lamina, below which lie the layers of the dermis.
Stratum spinosum
spiny in appearance due to the protruding cell processes that join the cells via a structure called a desmosome.
Stratum lucidum
A smooth, seemingly translucent layer of the epidermis located just above the stratum granulosum and below the stratum corneum.
Stratum corneum
he most superficial layer of the epidermis and is the layer exposed to the outside environment. The increased keratinization (also called cornification) of the cells in this layer gives it its name. There are usually 15 to 30 layers of cells in the stratum corneum.
Dermis
The dermis is made of two layers of connective tissue that compose an interconnected mesh of elastin and collagenous fibers, produced by fibroblasts.
Papillary Layer
The papillary layer is made of loose, areolar connective tissue, which means the collagen and elastin fibers of this layer form a loose mesh.
Reticular Layer
Underlying the papillary layer is the much thicker reticular layer, composed of dense, irregular connective tissue.
Hypodermis
The hypodermis (also called the subcutaneous layer or superficial fascia) is a layer directly below the dermis and serves to connect the skin to the underlying fascia (fibrous tissue) of the bones and muscles. It is not strictly a part of the skin, although the border between the hypodermis and dermis can be difficult to distinguish. The hypodermis consists of well-vascularized, loose, areolar connective tissue and adipose tissue, which functions as a mode of fat storage and provides insulation and cushioning for the integument.
