Exm 2 (ch 5) Flashcards
Function of integumentary system
Helps the body maintain its temperature
• Converts inactive vitamin D to its active form
• Provides sensory information – cutaneous sensations
• Helps maintain homeostasis in a number of ways
- Excretion and absorption
Avascular (no blood vessels)
Epidermis
Vascular layer of the skin
Dermis
Composed of areolar and adipose tissue. Vascular, Pacinian (lamellated corpuscles)
Hypodermis
Which layer in the dermis is made of loose areolar connective tissue?
Papillary layer
Which layer in the dermis is made of dense irregular connective tissue?
Reticular layer
Layers of the epidermis from superficial to deep
stratum corneum, stratum lucidum (found only in thick skin), stratum granulosum, stratum spinosum (largest), stratum basale.
The four major cells in the epidermis
Keratinocytes (90%, produce keratin (protective and waterproof)), Melanocytes (8%), Intraepidermal macrophages (Langerhans cells), Tactile epithelial cells (Merkel cells) (located in the stratum basale (deep layer))
25-30 layers of dead keratinocyte cells, cytoplasm replaced with keratin. Most layer of cells
Stratum corneum
constant exposure to friction causes increased cell production and keratin production in theses areas
Callus
4-6 layers of clear dead keratinocytes, only in thick skin of palms/soles, provides additional toughness to these areas. Is clear
Stratum lucidum (only present in thick skin)
3-5 layers of keratinocytes undergoing apoptosis (cell death), contains keratin precursor (keratohyalin) that can be converted to active, not on hands or soles of feet, lipid rich secretion, divides mitotic strata from dead cells. and spilling its contents to be released into the upper layer
Stratum granulosum
8-10 layers of dividing keratinocytes, spiky desmosomes, dendritic cells and melanocyte projections
Stratum spinosum
single row of rapidly diviging keratinocytes, melanocytes, tactile
epithelial cells (Merkel cells). Undergoing cell division.
Stratum basale
As cells move from deep to superficial epidermal layers they accumulate more and more keratin
Keratinization
hormone produced that stimulates cells of the
stratum basale to divide
Epidermal growth factor
Superficial portion of dermis (about one- fifth); consists of areolar connective tissue with thin collagen and fine elastic fibers; contains dermal ridges that house blood capillaries, tactile corpuscles, and free nerve endings.
Papillary region
Deeper portion of dermis (about four- fifths); consists of dense irregular connective tissue with bundles of thick collagen and some coarse elastic fibers. Spaces between fibers contain some adipose cells, hair follicles, nerves, sebaceous glands, and sudoriferous glands
Reticular region
produced by melanocytes in the
stratum basale
Melanin
red pigment in red blood
cells
Hemoglobin
yellow-orange pigment stored in
the stratum corneum and adipose tissue
Carotene
the inherited inability to produce melanin. Results in complete or partial absence of pigment in the skin, hair, and eyes.
Albinism
is a chronic disorder characterized
by partial or complete loss of
melanocytes from patches of skin
producing irregular white spots. The loss of melanocytes is related to an immune system malfunction where antibodies attack melanocytes.
Vitiligo
________ are connected to hair follicles
• Produce sebum (oil),
• Sebum: fats, cholesterol, degenerating cell parts, softens hair and prevents water loss
Sebaceous (oil) glands
_____ are sweat glands. Eccrine and apocrine
Sudoriferous glands
are modified sweat glands
located in the ear canal, specialized apocrine glands
Ceruminous glands
muscles extend from the
papillary dermis of the skin to the dermal root sheath at the base of the hair follicle
• This muscle contracts during physiological or emotional stress such as cold or fright – causes “goosebumps”
Arrector pili
