What is the Integumentary System - ANSWER: The skin -- a complex set of organs
that covers and protects body.
Name the organs that are involved in the integumentary system. - ANSWER: Skin,
hair, nails, and sebaceous (sweat and oil) glands
Name the functions of the integumentary system - ANSWER: Waterproof, cushion,
protect the deeper tissues, excrete waste, regulate temperature, provide sensory
input and synthesize vitamin D.
How do the structures of the integumentary system relate to its functions? -
ANSWER: Outer layer - epidermis has keratinized protective layer; second layer-
dermis has secretion glands, blood vessels, hair follicles and receptors; third layer -
subcutaneous has fatty cushion.
How do the structures of the integumentary system work together to maintain
homeostasis in the body? - ANSWER: Provides protection, regulation of body
temperature (sweat or shiver), sensory reception, water balance, synthesis of
vitamins and hormones and absorption of materials.
The Skin - ANSWER: 1.5-4.0 millimeters (mm), composed of two distinct regions, the
epidermis and dermis
Epidermis - ANSWER: Composed of epithelial cells, is the outermost protective shield
of the body. A keratinized stratified squamous epithelium consisting of 4 distinct cell
types and 4 or 5 distinct layers.
Dermis - ANSWER: Makes up the bulk of the skin, is a tough leathery layer composed
mostly of fibrous connective tissue. Only the dermis is vascularized.
Hypodermis (Superficial Fascia) - ANSWER: The subcutaneous tissue deep to the skin.
It is not part of the skin, but it shares some of the skins protective functions. It is
superficial to the tough connective tissue wrapping (fascia) of the skeletal muscles,
consists mostly of adipose tissue. Functions: Anchors the skin to the underlying
structures (mostly muscle), acts as a shock absorber.
Name the cells of the Epidermis - ANSWER: Keratinocytes, Melanocytes, Epidermal
Dendritic cells (Langerhans' cells), and Merkel or tactile cells.
Keratinocytes - ANSWER: Main role is to produce keratin, the fibrous protein that
helps give the epidermis its protective properties.
Melanocytes - ANSWER: The spider-shaped epithelial cells that synthesize the
pigment melanin, are found in the deepest layer of the epidermis. As melanin is
made it is accumulated in membrane bound granules called melanosomes, that are
, moved along actin filaments by motor proteins to the ends of melanocytes
processes. from there taken up by keratinocytes. Accumulate in superficial side of
keratinocyte nucleus. (All humans have same number of melanocytes)
Epidermal Dendritic Cells - ANSWER: Arise from bone marrow and migrate to the
epidermis. Also called Langerhans cells.
Functions: they ingest foreign substances and are key activators of the immune
system.
Merkel or Tactile Cells - ANSWER: Are present at the epidermal-dermal junction.
Shaped like a spiky hemisphere. Each cell is associated with a disclike sensory nerve
ending. (touch receptors)
Layers of the Epidermis - ANSWER: Thick skin which covers the palms, fingertips, and
soles of feet; Epidermis consists of 5 layers, or strata (bed sheets); superficial to
deep: Stratum Corneum, Stratum Lucidum, Stratum Granulosum, Stratum Spinosum
and Stratum Basale.
Layers of the Epidermis (b) - ANSWER: Superficial to deep: Stratum Corneum,
Stratum Lucidum, Stratum Granulosum, Stratum Spinosum and Stratum Basale.
MNEUMONIC: Cora, Luci's Grandma, Spins Baseballs.
Stratum Corneum (Horny Layer) - ANSWER: 20 to 40 cell layers of dead, flat
keratinized, membranous sacs, accounts for up to 3/4s of epidermal thickness.
Functions: Protects from abrasion and penetration, Waterproofs, Barrier against
biological, chemical, and physical assaults
Stratum Lucidum (Clear Layer) - ANSWER: Appears as a clear translucent band just
above the stratum granuosum. 2 to 3 rows of flat, dead keratinocytes.
Stratum Granuosum (Granular Layer) - ANSWER: Thin layer that consists of 3 to 5
layers in which keratinocyte appearance changes drastically and the process of
keratinization (in which the cells fill with the protein keratin) begins. Keratohyaline
help form keratin in upper layers, and lamellated granules spew a water resistent
glycolipid into the extracellular space slowing water loss across epidermis making the
outter skin more tough.
Stratum Spinosum (Prickly Layer) - ANSWER: Several cell layers thick, cells contain a
weblike system of intermediate prekeratin filaments attached to desmosomes.
Keratinocytes appear to have spines and are scattered among abundant melanin
granules and Langerhans' cells.