Chapter 5 - The Integumentary System Flashcards
Which layer of skin is the outermost protective shield of the body?
the epidermis
What is the epidermis composed of?
epithelial cells
What makes up the bulb of the skin?
dermis
What is dermis composed of?
It is a tough, leathery layer composed mostly of fibrous connective tissue
How much does your skin weight?
9-11 lbs
T or F. Only the epidermis is vascularized
False. Only the DERMIS is vascularized. Nutrients reach the epidermis by diffusing trough the tissue fluid from blood vessels in the dermis.
What is the function of the hypodermis? (aka superficial fascia)
Besides storing fat (adipose tissue) it anchors the skin to the underlying structures. It is technically not part of the skin but shares it’s protective functions. It thickens markedly when a person gains weight!!
Structurally, _____ is a keratinized stratified squamous epithelium consisting of 4 distinct cell types and 4 or 5 distinct layers.
epidermis
Name the 4 types of cells populating the epidermis.
KMDT
Keratinocytes
Melanocytes
Dendritic cells
Tactile Cells
What fibrous protein helps give epidermis its protective properties?
keratin
Most epidermal cells are what type?
Keratinocytes. Their chief role is to produce keratin.
Keratinocytes arise from the deepest part of the epidermis from a cell layer called?
Stratum basale
T or F. By the time keratinocytes reach the skins surface they are dead.
T
Found in the deepest layer of the epidermis and synthesize the pigment melanin. Spider shaped.
Melanocytes
As melanin’s made, it accumulates in membrane-bound granules called?
melanosomes. These melanin granules accumulate on the superficial or “sunny” side of the keratinocyte nucleus forming a pigment shield that protects the nucleus from damaging effects of UV radiation
Star shaped cells who arise from bone marrow and migrate to the epidermis.
Dendritic cells. Aka Langerhans cells.
What do dendritic cells do?
they ingest foreign substances and are key activators of our immune system.
What type of cells are present at the epidermal-dermal junction and allow us to feel things through a dislike sensory nerve ending?
Tactile Cells. Aka Merkel cells.
Name the 5 layers (strata) of thick skin.
From deep to superficial: Stratum basal, Stratum spinosum, Stratum granulosum, Stratum lucidum and Stratum corneum.
Which of the 5 layers (strata) is missing in thin skin?
Stratum lucidum. And the other strata are thinner.
Where is the thickest skin in the body located?
upper back
The deepest epidermal layer, attached to the underlying dermis. Consists of a single layer of constantly renewing stem cells which represent the youngest keratinocytes.
Stratum basale (basal layer). Aka stratum germinativum (“germinating” layer)
10-25% of the cells in the stratum basal are?
melanocytes