BIOL 121 Chp 5 Vocab: Integumentary System (Skin)

integumentary system

the skin and its accessory structures that guard the body's physical and biochemical integrity, maintain a constant body temperature, and provide sensory information about the surrounding environment

dermatology

the medical specialty dealing with diseases of the skin

skin

the external covering of the body consisting of a superficial, thinner epidermis and a deep, thicker dermis that is anchored to a subcutaneous layer

epidermis

the superficial, thinner layer of skin, composed of keratinized stratified squamous epithelium

dermis

a layer of dense irregular connective tissue lying deep to the epidermis

subcutaneous layer

a continuous sheet of areolar connective tissue and adipose tissue between the dermis of the skin and the deep fascia of the muscles

hypodermis

another name for the subcutaneous layer

Pacinian corpuscle

a type of nerve ending located in the subcutaneous layer that is sensitive to pressure; also described as "lamellated

keratinocyte

the most abundant type of epidermal cell, which helps protect the skin and underlying tissue from heat, microbes, and chemicals

keratin

an insoluble protein that makes up hair and nails

melanocyte

an epidermal cell that produces the pigment melanin which contributes to skin color and absorbs damaging ultraviolet (UV) light

melanin

a dark black, brown, or yellow pigment found in the skin and hair

Langerhans cell

an epidermal dendritic cell that that functions as an antigen-presenting cell during an immune response

Merkel cell

a type of epidermal cell that makes contact with a tactile disc, which functions in touch

thin skin

found in most areas of the integumentary system, with an epidermis consisting of four layers of keratinocytes

thick skin

found in areas of the integumentary system exposed to significant friction, with an epidermis consisting of all five layers of keratinocytes

stratum basale

the deepest layer of the epidermis consisting of stem cells capable of undergoing cell division to form new cells

stratum spinosum

a layer of the epidermis that provides strength and flexibility to the skin

stratum granulosum

a layer of the epidermis that marks the transition between the deeper, metabolically active strata and the dead cells of the more superficial strata

stratum lucidum

a layer of the epidermis found only in the thick skin of the fingers, palms, and soles

stratum corneum

the most superficial layer of the epidermis consisting of dead cells

callus

an abnormal thickening of the epidermis caused by constant exposure to friction

keratinization

the replacement of cell contents with new protein, occurring as cells move to the skin surface over 2-4 weeks

psoriasis

a chronic skin disorder characterized by a rapid division and movement of keratinocytes through the epidermal strata

papillary region

the superficial area of the dermis composed of areolar connective tissue, dermal papillae, Meissner corpuscles of touch, and free nerve endings

dermal papilla

a fingerlike projection of the papillary region of the dermis that may contain blood capillaries or Meissner corpuscles (of touch)

Meissner corpuscle

a tactile nerve ending receptor in the dermal papillae that is sensitive to touch

free nerve ending

dendrites that lack any obvious structural specialization; used to generate sensations of warmth, coolness, pain, tickle, and itch

reticular region

the deeper part of the dermis consisting of dense irregular connective tissue containing bundles of collagen fibers and some elastic fibers

extensibility

the ability of skin to stretch, due to the combination of collagen and elastic fibers in its reticular region

elasticity

the ability of a tissue to return to its original shape after contracting or stretching

epidermal ridge

this can help increase friction for improved grasping ability and provides the basis for fingerprints and footprints

hemoglobin

the oxygen-carrying pigment in red blood cells that provides the pink to red color of the epidermis

carotene

yellow-orange pigment present in the epidermis, accounting for the yellowish coloration of skin

albinism

an abnormal, nonpathological, partial, or total absence of pigment in skin, hair, and eyes

vitiligo

the complete or partial loss of melanocytes from patches of the skin resulting in irregular white spots

cyanotic

the bluish color of the mucous membranes, nail beds, and skin that occurs when blood is not picking up an adequate amount of oxygen from the lungs

jaundice

a yellowish appearance to the skin and whites of the eyes due to a buildup of the pigment bilirubin

erythema

skin redness usually caused by dilation of the capillaries

pallor

the paleness of skin resulting from shock or anemia

pilus

found on most skin surfaces except the palms, palmar and plantar surfaces of the digits, and soles

shaft

the superficial portion of the hair

root

the portion of a hair that penetrates into the dermis and sometimes the subcutaneous layer

hair follicle

a structure composed of epithelium that surrounds the root of a hair

bulb

the base of a hair follicle and its surrounding dermal root sheath, containing the papilla of the hair and matrix

arrector pili

the smooth muscles attached to hair follicles

hair root plexus

a collection of dendrites of neurons surrounding each hair follicle that are sensitive to touch

alopecia

the partial or complete lack of hair resulting from genetic factors, aging, endocrine disorders, chemotherapy, or skin disease

lanugo

the fine, nonpigmented, downy hairs that cover the fetus

terminal hair

hair located on the head, eyelashes, and eyebrows

vellus hair

short, fine, pale hair ("peach fuzz") that replaces lanugo

sebaceous gland

an exocrine gland in the dermis associated with a hair follicle that secretes oil (sebum)

sebum

the lipid-rich secretion of the sebaceous glands that moistens hair, waterproofs and softens the skin, and inhibits bacterial growth

sudoriferous gland

an exocrine gland that produces and secretes perspiration

thermoregulation

the homeostatic balance of body temperature

ceruminous gland

a modified gland in the external auditory meatus that secretes earwax

cerumen

earwax

nail

the hard, keratinized epidermal cells located over the dorsal surfaces of the terminal portions of the fingers and toes

nail body

the visible portion of the nail

nail root

the portion of a nail that is buried in a fold of skin

lunula

the moon-shaped white area at the base of a nail

eponychium

a narrow band of epidermis at the proximal border of a nail; the cuticle

nail matrix

the part of the nail beneath the body and root from which the nail is produced

blood reservoir

a function of the skin provided by the extensive network of blood vessels in the dermis

cutaneous sensation

a feeling of touch, pressure, vibration, tickle, heat, cold, or pain that arises in the skin

excretion

the elimination of metabolic wastes from the body

contact inhibition

a cellular response where epidermal cells stop migrating upon encountering each other

inflammatory phase

the stage where a blood clot forms in a deep wound and loosely unites the wound's edges

inflammation

a vascular and cellular response that helps eliminate microbes, foreign material, and dying tissue in preparation for repair

migratory phase

the stage in wound healing where the blood clot becomes a scab, and epithelial cells migrate beneath the scab to bridge the wound

granulation tissue

the cells that divide to restore skin after an injury

proliferative phase

the stage in wound healing characterized by extensive growth of epithelial cells beneath the scab, deposition of collagen fibers by fibroblasts, and continued growth of blood vessels

maturation phase

the stage in wound healing where a scab sloughs off once the epidermis has been restored to its normal thickness