Chapter 5 - The Integumentary System Flashcards
Integumentary System
Composed of skin, hair, oil, sweat glands, nails and sensory receptors. Temperature, Protection, Sensory.
Skin or cutaneous membrane
AKA Cutaneous Membrane, largest organ
Epidermis
Superifical, Avascular
Dermis
Connective tissue, Vascular
Subcutaneous layer or hypodermis
In the dermis, consists of areolar and adipose tissues. Fibers that extend from dermis anchor the skin to the subQ layer, attaching to fascia. Storage for fat, has large blood vessels.
Lamellated corpuscle or pacinian corpuscle
subQ contains these nerve endings that are sensitive to pressure.
Keratinocyte
90% of epidermis cells. Arranged in 4or5 layers to produce protein. Also produce lamellar granules
Keratin
Protein, tough, fibrous to protect.
Melanocyte
8% of epidermis cells. Produce pigment, transfer melanin granules to keratinocytes.
Melanin
Yellow-red or brown-black. Absorbs UV, protective veil over nucleus.
Intraepidermal Macrophages / Langerhans Cell
From red bone marrow to epidermal cells. Immune responses, easily damaged by UV.
Tactile Epithelial Cells or Merkel Cell
least numerous. Deepest layer of epidermis contact disks for touch.
Tactile Disk or Merkel Disk
Flattened process of a sensory neuron for touch.
Thin and Thick skin
Thin=four strata and thin stratum corneum.
Thick=where exposure to friction is greatest, five strata and thick stratum corneum.
stratum basale or stratum germinativum
Deepest layer of epidermis. Single row of cuboidal or columnar keratinocytes, some are stem cells.
keratin intermediate filaments (tonofilaments)
The cytoskeleton within keratinocytes include these, to form keratin.
Stratum Spinosum
- 8-10 layers of keratinocytes. Coarser bundles of keratin. Have spinelike projections which insert into desmosome to joins cells together for strength and flexibility.
Stratum Granulosum
Middle. 3-5 layers. Apoptosis. Keratinocytes carry on vital metabolic reactions. (transition layer)
Keratohyalin
Dark staining granules, assembles keratin intermediate filaments into keratin.
Lamellar Granules
Inside keratinocytes are membrane enclosed lamellar granules- fuse with the plasma membrane and release a lipid-rich secretion. (water-repellant)
Stratum Lucidum
Only in thick skin. 4-6 layers.
Stratum Corneum
25-30 layers, no nuecleus or organeles. Cells overlap, continuously shed
Callus
Constant exposure of skin to friction stimulates increased cell production and keratin production that results in the formation of a callus, an abnormal thickening of the stratum corneum.
Keratinization
As cells move from one epidermal layer to the next they accumulate more and more keratin.
Psoriasis
Chronic skin disorder, keratinocytes divide more quickly and shed prematurely- need to suppress cell division.
Papillary Region
Thin collagen and fine elastic fibres.
Dermal Papilla
Small nipple-shaped structures that project into the undersurface of the epidermis.
Capillary Loops
Blood vessels.
Corpuscle of Touch or Meissner Corpuscle
nerve endings sensitive to touch
Free nerve ending
Dendrites that lack structural specialization but initiate signals for sensations of warmth, coolness, pain, tickling, itching.
Reticular Region
Attached to the subcutaneous layer, contains bundles of thick collagen fibers, scattered fibroblasts, and various wandering cells.
Extensibility
Strength/Ability to stretch
Elasticity
Ability to return to original shape after stretching.
Epidermal Ridge
Surfaces of palms, fingers, soles, toes. Straight lines, loops, whorls. Ridges create strong bond for mechanical stress. Increase surface area and grip by increasing friction.
Fingerprints/Footprints
.Ducts of sweat glands open on the tops of epidermal ridges as sweat pores, forming prints when touching a smooth object. not even twins match.
Pheomelanin
Yellow to red
Eumelanin
Brown to black
Nevus
Benign localized overgrowth of melanocytes
Albinism and Vitiligo
Inability to produce melanin vs Partial or loss of melanocytes from patches.
Carotene
Yellow-orange pigment, precursor for vitamin A, excess stored in skin.
Cyanotic, Jaundice, Erythema, Pallor
Bluish - Yellow - Redness - Pale
Functions of hair
Guards scalp, decreases heat loss, prevent foreign particles.
Shaft
Superficial portion above skin
Root
penetrates into dermis
Medulla, cortex, cuticle
two or three rows of irregularly shaped cells that contain pigment molecules.
Elongated cells. Cuticle outermost, heavily keratinized.
Hair follicle
surrounding root, epithelial root sheath
Bulb
base of each hair follicle surrounding dermal root sheath.
Matrix
responsible for growth of existing hairs.
Arrector pili muscle
Smooth muscle - contracts with cold or fright to raise hair
Hair root plexus
Dendrites of neurons, sensitive to touch, generating nerve impulses
Hair growth; stages.
Growth-Regression-Resting
Alopecia
Baldness
Lanugo
Very fine, non pigmented downy hairs covering fetus.
Terminal hairs
Eyebrows, lashes, scalp, heavily pigment.
Vellus Hairs
Lanugo of the rest of the body, peach fuzz.
Hair colour
Amount and type of melanin
Sebaceous gland or oil gland
Simple, branched acinar (rounded) glands. Usually connected to hair follicles,
Acne
Inflammation of sebaceous glands because of bacteria
Sudoriferous gland
Release sweat into hair follicles or skin.
Eccrine sweat gland
Simple, coiled tubular, more common, From dermis to surface of epidermis
Thermoregulation
Sweat evaporates so heat leaves body surface
Thermoregulatory sweating
Forehead and scalp then rest of body
Insensible and sensible perspiration
Evaporates before perceived as moisture vs seen as moisture
Emotional sweating
Stress, palms, soles, and axillae.
Apocrine sweat gland
SKin of axillae, groin, areolae, bearded, clit, labia minora, deep dermis to hair follicles. sweat plus lipids and proteins, emotional stress or sex
Ceruminous gland
External auditory canal, subcutaneous layer to external auditory canal or ducts of sebaceous glands. Cerumen (wax) prevents water and foreign material.
Nail body
Visible plate
Hyponychium
Secures nail to fingertip
Eponychium
cuticle
Free edge
Extend past digit
Nail root
Buried in fold of skin
Lunula
White moon
Nail matrix
Cells divide mitotically
Thermoregulation
Liberating sweat or adjusting blood flow
Blood reservoir
8-10% of total blood flow in extensive network of blood vessels (in dermis)
Protection
Keratin protects from microbes, abrasion, heat. Lipids inhibit evaporation of water, Melanin UV,
Cutaneous sensations
Touch, pressure, vibration, tickling, warm, cool, pain
Excretion and absorption
excretes water some salt, co2, ammonia and urea.
Absorbs fat-soluble vitamins (ADEK), certain drugs, oxygen and co2.
Can absorb acetone, ccl4, lead, mercury, arsenic, cortisone, steoids.
Synthesis of vitamin D
Enzymes in liver and kidneys modify activated UV molecule to produce calcitriol.
Epidermal wound healing
.Basal cells of the epidermmis break contact with basement membrane, migrate until meeting. EGF stimulates basal stem cells to divide and replace the missing ones, thickening epidermis.
Inflammatory phase
Blood clot loosely unites edges. Inflammation eliminates microbes, enhances delivery.
Migratory phase
Clot becomes scab, epithelial cells migrate to bridge the wound. Fibroblasts synthesize scar tissue, blood vessels regrow.
Granulation tissue
Tissue filling wound in migratory phase
Proliferative phase
Extensive growth of epithelial cells, deposition by fibroblasts of collagen fibers, growth of blood vessels
Maturation phase
Scab sloughs off, collagen organizes, fibroblasts decrease, blood vessels normal.
Fibrosis
Scar tissue formation
Pressure ulcers
Constant deficiency of blood flow to tissues.
Sebum
a mixture of triglycerides, cholesterol, proteins, and inorganic salts. Sebum coats the surface of hairs and helps keep them from drying and becoming brittle. Sebum also pre- vents excessive evaporation of water from the skin, keeps the skin soft and pliable, and inhibits the growth of some (but not all) bacteria.
