Chapter 5 Flashcards
Integumentary System
composed of the skin, hair, oil and sweat glands, nails, and sensory receptors.
Dermatology
the medical specialty that deals with the structure, function,
and disorders of the integumentary system.
Another word for skin
cutaneous membrane
Skin
covers the external surface of the body and is the largest organ of the body in weight.
Epidermis
The superficial, thinner portion of skin, which is composed of
epithelial tissue
Dermis
deeper, thicker connective tissue portion
Subcutaneous Layer
Deep to the dermis, but not part of the skin. this layer consists of areolar and adipose tissues.
Another word for Subcutaneous Layer
hypodermis
lamellated
corpuscles
(pacinian corpuscles)
Nerve endings in the subcutaenous layer. Sensitive to pressure.
What is the epidermis composed of (4 cells)
keratinized stratified squamous
epithelium. It contains four principal types of cells: keratinocytes,
melanocytes, intraepidermal macrophages, and tactile epithelial cells
keratinocytes
90% of epidermal cells. which are arranged
in four or five layers and produce the protein keratin
Keratin
a tough, fibrous protein that helps protect the skin and underlying tissues from abrasions,
heat, microbes, and chemicals.
lamellar
granules
Produced by keratinocytes. Release a water-repellent sealant that decreases water entry and loss and inhibits the entry of foreign materials.
Melanocytes
8% of epidermal cells. develop from the ectoderm of a developing embryo and produce the pigment melanin. Their
long, slender projections extend between the keratinocytes and
transfer melanin granules to them.
Melanin
a yellowred or brown-black pigment that contributes to skin color and absorbs damaging ultraviolet (UV) light.
Intraepidermal macrophages
arise from red bone marrow and migrate to the epidermis where they constitute a small fraction of the epidermal cells. They participate in immune responses mounted against microbes that invade the skin, and are easily damaged by UV light. Their role in the immune response is to help other cells of the immune system recognize an invading microbe and destroy it.
Tactile epithelial cells
the least
numerous of the epidermal cells. They are located in the deepest layer
of the epidermis, where they contact the flattened process of a sensory neuron, a structure called a tactile disc
Tactile Disc
Sensory neuron that detects touch sensations.
the epidermis has four strata or layers—stratum basale, stratum spinosum, stratum granulosum, and a thin stratum corneum. This is called:
Thin Skin
Where exposure to friction is greatest, such as in the
fingertips, palms, and soles, the epidermis has five layers—stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and
a thick stratum corneum. This is called:
Thick Skin
Stratum Basale
Deepest layer of epidermis. composed of a single row of cuboidal or columnar keratinocytes. Some cells in this layer
are stem cells.
stem cells
undergo cell division in Stratum Basale to continually produce new keratinocytes.
Stratum Spinosum
consists of numerous keratinocytes arranged in 8–10 layers. Superficial to Stratum Basale
Stratum Granulosum
consists of three to five layers of flattened keratinocytes that are undergoing apoptosis.
keratohyalin
A distinctive feature of cells in Stratum Granulosum is the presenceof darkly staining granules of this protein.
Lamellar Granules
present in the keratinocytes. fuse with the plasma membrane and release a lipid-rich secretion.
Stratum Lucidum
present only in the thick skin of areas such as the fingertips, palms, and soles. It consists of four to six layers of flattened clear, dead keratinocytes that contain large amounts of keratin and
thickened plasma membranes.
Statum Corneum
25 to 30 layers of flattened dead
keratinocytes. extremely thin, flat,
plasma membrane–enclosed packages of keratin that no longer
contain a nucleus or any internal organelles.
final product
of the differentiation process of the keratinocytes
Stratum Corneum
Callus
an abnormal
thickening of the stratum corneum
Keratinization
Newly formed cells in the stratum basale are slowly pushed to the
surface. As the cells move from one epidermal layer to the next, they accumulate more and more keratin.
Epidermal Growth Factor
Hormone like proteins that play a role in keratinzation
Dermis
The second, deeper part of the skin. composed of dense
irregular connective tissue containing collagen and elastic fibers.
Papillary Region
makes up about one-fifth of the thickness
of the total layer of the dermis. contains thin collagen and fine
elastic fibers.
dermal papillae
small, nipple-shaped structures that project into the undersurface of the epidermis
Capillary Loops
Blood vessels that dermal papillae contain.