Integumentary System Flashcards
Structures that are part of the integument.
- Skin.
- Hair.
- Nails.
- Glands.
- protects against U V light, microorganisms, water loss.
Protection
- sensory receptors for heat, cold, touch, pressure, pain.
Sensation
- modulation of blood flow through the skin and activity of sweat glands.
Temperature regulation
from a molecule made in the skin when exposed to UV light.
Vitamin D production
- small amounts of waste products eliminated.
Excretion
- Superficial layer of stratified squamous epithelial tissue.
- Protection and reduces water loss.
Epidermis
- Deep layer of connective tissue.
- Structural strength.
Dermis
- Not part of skin.
- Loose connective tissue that connects skin to underlying structures.
Subcutaneous tissue.
- Avascular; nourished by diffusion from capillaries of the papillary layer of the dermis.
- Composed of epithelial cells arranged into layers or strata.
- Separated from dermis by basement membrane.
Epidermis
- most cells.
- Produce keratin for strength.
Keratinocytes
- contribute to skin color. Melanin produced by these cells then transferred to keratinocytes.
- Same number of melanocytes in all people.
Melanocytes
- part of the immune system.
Langerhans cells
*detect light touch and superficial pressure.
Merkel cells
- as cells move outward through the layers they fill with keratin, die, and serve as a layer that resists abrasion and forms permeability layer.
Keratinization
- Deepest portion of epidermis and single layer of cuboidal or columnar cells.
- High mitotic activity; keratinocyte stem cells undergo mitosis about every 19 days;
- one daughter cell remains in the stratum basale to divide again, while the other daughter cell is pushed to the surface and becomes keratinized.
- Desmosomes hold the keratinocytes together and provide structural strength.
- It takes 40 to 56 days to move from the stratum basale to the surface and be sloughed off.
Stratum basale (germinativum)
- Eight to ten layers of many-sided cells that flatten as they are pushed upward.
- Contain new desmosomes, lipid-filled lamellar bodies, and additional keratin fibers.
Stratum spinosum
- Two to five layers of flattened, diamond-shaped cells.
- Contains protein granules of keratohyalin that accumulate in the cytoplasm.
- Lamellar bodises move to the plasma membrane and release their lipid contents into the extracellular space.
- In superficial layers, nucleus and other organelles degenerate and cell dies; the keratin fibers and keratohyalin granules do not degenerate.
Stratum granulosum
- Thin, clear zone of dead keratinocytes with indistinct boundaries.
- Found only in palms and soles.
Stratum lucidum
- Most superficial and consists of 25 or more layers of dead, overlapping squamous cells joined by desmosomes called cornified cells.
- Cell remnants have a soft protein envelop of keratin, a mixture of keratin fibers and keratohyalin.
Stratum corneum
- this (designation refers only to the epidermis)
- Has all 5 epithelial strata.
- Found in areas subject to pressure or friction.
- Palms of hands, fingertips, soles of feet.
- Fingerprints and footprints.
- Papillae of underlying dermis in parallel rows.
Thick Skin
- Composed of 4 strata (no stratum lucidum).
- More flexible than thick skin.
- Covers rest of body.
- Hair grows here.
Thin skin
Increase in number of layers in stratum corneum. When this occurs over a bony prominence, a corn forms.
Callus
- Determined by 3 factors: pigments in the skin, blood circulating through the skin
Skin Color
provides for protection against UV light. Group of chemicals derived from amino acid tyrosine. Colored brown to black, may be yellowish or reddish
Melanin
processes extend between keratinocytes; deposit melanosomes (vesicles that contain melanin)
Melanocytes
deficiency or absence of pigment; production determined by genetics, hormones, exposure to light.
Albinism
yellow pigment from vegetables; accumulates in stratum corneum, in adipose cells of dermis, and in subcutaneous tissue.
Carotene
Blood circulating through the skin imparts reddish hue and increases during blushing, anger, inflammation.
Skin Color
- blue color caused by decrease in blood oxygen content.
Gyanosis
- red color caused by increased blood flow.
- Thickness of stratum corneum impacts color.
- Thicker areas can be yellowish.
- Pigments and other substances in the dermis or subcutaneous tissue may impart a bluish color to the skin; the deeper, the bluer.
Erythema
- red color caused by increased blood flow.
- Thickness of stratum corneum impacts color.
- Thicker areas can be yellowish.
- Pigments and other substances in the dermis or subcutaneous tissue may impart a bluish color to the skin; the deeper, the bluer.
Erythema
- The most common type of cancer.
- Most result from damage from UV radiation that damages the DNA in epidermal cells.
- The amount of melanin affects the likelihood of developing skin cancer; fair-skinned people are at a greater risk than dark-skinned people.
Skin Cancer
Three major types of Skin Cancer
- Basal cell carcinoma
- Squamous cell carcinoma
- Melanoma
Three major types of Skin Cancer
- Basal cell carcinoma
- Squamous cell carcinoma
- Melanoma
- Most common
- Cells of stratum basal
- Varied appearance
- Cured by removal or destruction
Basal cell carcinoma
- Cells of stratum spinosum
- Varied appearance; may bleed
- Most cases cured by removal or destruction
Squamous cell carcinoma
- Cells of stratum spinosum
- Varied appearance; may bleed
- Most cases cured by removal or destruction
Squamous cell carcinoma
- Gives structural strength. C.T. with many fibers (collagen, elastic, and reticular), fibroblasts, macrophages, and adipocytes.
- Contains nerves, blood vessels, hair follicles, smooth muscles, glands, and lymphatic vessels.
Dermis
pain, itch, tickle, temperature, touch, pressure, two-point discrimination.
Sensory functions
Superficial. Areolar with lots of elastic fibers, dermal papillae, capillary beds. Friction ridges form fingerprints. Whorls of ridges. Touch receptors (Meissner, Pacinian, and Ruffini), free nerve endings sensing pain.
Papillary
Deep. Dense irregular C.T. of collagen and elastic fibers. Also contains some adipose tissue, hair follicles, nerves, oil glands, ducts of sweat glands, heat sensors.
Reticular
- elastic and collagen fibers oriented in some directions more than in others. Important in surgery.
- If incision parallel to lines, there is less gapping, faster healing, less scar tissue.
- If skin is overstretched, stretch marks occurs
Cleavage (tension) lines:
- Deep to skin.
- Also called hypodermis.
- Consists of loose connective tissue with collagen and elastic fibers.
Subcutaneous tissue
3 types of injections
1) Intradermal
2) Subcutaneous
3) Intramuscular
into the dermis; skin taut; needle at shallow angle
Intradermal
into subcutaneous layer; pinch skin; short needle
Subcutaneous
long needle perpendicular to skin
Intramuscular
delicate, unpigmented hair of the fetus
Lanugo
long, course, pigmented hair of the scalp, eyelids, eyebrows, and with puberty, axilla, pubic, and face.
Terminal hair
fine, short hair on the rest of the body.
Vellus hair
protrudes above skin surface.
Shaft
located below surface; base of root is the hair bulb.
Root
- central axis.
Medulla
- forms bulk of hair.
Cortex
- forms hair surface. Hair bulb expanded base of root
- Internal matrix is source of hair.
- Dermis projects into bulb as hair papilla, serves as blood supply.
Cuticle
part of dermis that surrounds the epithelial root sheath.
Dermal root sheath
- with internal and external parts.
- Internal part contains stratum basale that may remain after injury and supply a source of new epidermis.
- When hairs are pulled out, internal part comes out and is visible as white bulb.
Epithelial root sheath
Growth and resting stages are cyclic.
Hair Growth
- cells added at base and hair elongates.
Growth stage
- follicle shortens and holds hair in place. Rest, then hair falls out of follicle. New hair begins.
- The amount of time spent in each stage depends on the type or location of the hair.
Resting stage
pattern baldness most common cause.
Permanent hair loss
- is spot baldness most likely due to an autoimmune response.
Alopecia areata
- Caused by varying amounts and types of melanin.
- Melanin can be black-brown and red. Color is controlled by several genes.
Hair Color
- Caused by varying amounts and types of melanin.
- Melanin can be black-brown and red. Color is controlled by several genes.
Hair Color
- Type of smooth muscle.
- Extends from the dermal root sheath of the follicle to the papillary layer of the dermis.
- Muscle contraction causes hair to “stand on end”.
- Skin pushed up by movement of hair follicle to produce “goose bumps”.
Arrector pili.
- Holocrine (death of secretory cells).
- Oily secretion called sebum.
- Prevents drying and inhibits some bacteria.
- Most empty into hair follicle.
- Exceptions: lips, meibomian glands of eyelids, genitalia.
Sebaceous Glands.
Two types traditionally called apocrine and merocrine, but apocrine may secrete in a merocrine or holocrine fashion
Sweat (Sudoriferous) Glands
- Most common; numerous in palms and soles.
- Simple coiled tubular glands.
- Open directly onto surface of skin. Have own pores.
- Coiled part in dermis, duct exiting through epidermis.
- Produce isotonic fluid (sweat) containing mostly water and some wastes.
- Important role in body temperature regulation.
Eccrine (merocrine) glands.
