Ch 5 PHYL 141 Exam

albinism

genetic disorder that affects the skin in which there is no melanin production

apocrine sweat gland

type of sweat gland that is associated with hair follicles in the armpits and genital regions

arrector pili

smooth muscle that is activated in response to external stimuli that pull on hair follicles and make the hair stand up

basal cell

type of stem cell found in the stratum basale and in the hair matrix that continually undergoes cell division producing the keratinocytes of the epidermis

basal cell carcinoma

cancer that originates from basal cells in the epidermis of the skin

bedsore

sore on the skin that develops when regions of the body start necrotizing due to constant pressure and lack of blood supply; also called decubitus ulcers

callus

thickened area of skin that arises due to constant abrasion

cortex

in hair

cuticle

in hair

dermal papilla

extension of the papillary layer of the dermis that increases surface contact between the epidermis and dermis

dermis

layer of skin between the epidermis and hypodermis composed mainly of connective tissue and containing blood vessels

desmosome

structure that forms an impermeable junction between cells

eccrine sweat gland

type of sweat gland that is common throughout the skin surface; it produces a hypotonic sweat for thermoregulation

eczema

skin condition due to an allergic reaction which resembles a rash

elastin fibers

fibers made of the protein elastin that increase the elasticity of the dermis

eleiden

clear protein-bound lipid found in the stratum lucidum that is derived from keratohyalin and helps to prevent water loss

epidermis

outermost tissue layer of the skin

eponychium

nail fold that meets the proximal end of the nail body; also called the cuticle

fourth-degree burn

burn in which full thickness of the skin and underlying muscle and bone is damaged

hair

keratinous filament growing out of the epidermis

hair bulb

structure at the base of the hair root that surrounds the dermal papilla

hair follicle

cavity or sac from which hair originates

hair matrix

layer of basal cells from which a strand of hair grows

hair root

part of hair that is below the epidermis anchored to the follicle

hair shaft

part of hair that is above the epidermis but is not anchored to the follicle

hypodermis

connective tissue connecting the integument to the underlying bone and muscle

hyponychium

thickened layer of stratum corneum that lies below the free edge of the nail

integumentary system

skin and its accessory structures

keratin

type of structural protein that gives skin hair and nails their hard water-resistant properties

keratinocyte

cell that produces keratin and is the most predominant type of cell found in the epidermis

keratohyalin

granulated protein found in the stratum granulosum

Langerhans cell

specialized dendritic cell found in the stratum spinosum that functions as a macrophage

lunula

basal part of the nail body that consists of a crescent-shaped layer of thick epithelium

medulla

in hair

Meissner corpuscle

receptor in the skin that responds to light touch

melanin

pigment that determines the color of hair and skin

melanocyte

cell found in the stratum basale of the epidermis that produces the pigment melanin

melanoma

type of skin cancer that originates from the melanocytes of the skin

melanosome

intercellular vesicle that transfers melanin from melanocytes into keratinocytes of the epidermis

Merkel cell

receptor cell in the stratum basale of the epidermis that responds to the sense of touch

nail bed

layer of epidermis upon which the nail body forms

nail body

main keratinous plate that forms the nail

nail cuticle

fold of epithelium that extends over the nail bed; also called the eponychium

nail fold

fold of epithelium that extends over the sides of the nail body holding it in place

nail root

part of the nail that is lodged deep in the epidermis from which the nail grows

Pacinian corpuscle

receptor in the skin that responds to vibration

papillary layer

superficial layer of the dermis made of loose areolar connective tissue

reticular layer

deeper layer of the dermis with a reticulated appearance due to abundant collagen and elastin fibers

scar

collagen-rich skin formed after wound healing that is different from normal skin

sebaceous gland

type of oil gland found in the dermis all over the body that lubricates and waterproofs skin and hair by secreting sebum

sebum

oily substance composed of a mixture of lipids that lubricates the skin and hair

second-degree burn

partial-thickness burn that injures the epidermis and a portion of the dermis

stratum basale

deepest layer of the epidermis made of epidermal stem cells

stratum corneum

most superficial layer of the epidermis

stratum granulosum

layer of the epidermis superficial to the stratum spinosum

stratum lucidum

layer of the epidermis between the stratum granulosum and stratum corneum found only in thick skin covering the palms soles and digits

stratum spinosum

layer of the epidermis superficial to the stratum basale characterized by the presence of desmosomes

stretch mark

mark formed on the skin due to a sudden growth spurt and expansion of the dermis beyond its elastic limits

sudoriferous gland

sweat gland

third-degree burn

burn that penetrates and destroys the full thickness of the skin

vitamin D

compound that aids absorption of calcium and phosphates in the intestine to improve bone health

vitiligo

skin condition in which melanocytes in certain areas lose the ability to produce melanin resulting in loss of color in patches

thick skin

skin found on the palms soles and digits that contains all five epidermal layers and lacks hair follicles and sebaceous glands

thin skin

skin with four epidermal layers that lacks a stratum lucidum and contains hair follicles and sebaceous glands

stratum germinativum

alternate name for the stratum basale where epidermal cell division occurs

tactile epithelial cell

sensory receptor cell in the epidermis also called a Merkel cell

intraepidermal macrophage

immune cell in the epidermis also called a Langerhans cell that destroys invading microbes

basement membrane

layer of intertwining collagen fibers that anchors the epidermis to the dermis

hemidesmosome

structure that attaches the epidermis to underlying tissues

eumelanin

dark brown or black form of melanin pigment

pheomelanin

reddish form of melanin pigment

carotene

dietary pigment that contributes to skin coloration

tyrosinase

enzyme required for melanin production

ultraviolet (UV) light

high-energy radiation that can damage DNA and stimulate melanin production

ABCDE rule of melanoma

method for identifying melanoma using asymmetry border color diameter and evolution

nevus

mole formed by localized growth of melanocytes

malignant melanoma

invasive melanoma capable of spreading throughout the body

thermoregulation

homeostatic control of body temperature through mechanisms such as sweating

friction ridges

epidermal ridges that form fingerprints

fingerprints

unique ridge patterns formed where the epidermis interacts with dermal papillae

photoaging

skin aging caused by ultraviolet damage to collagen and elastin fibers

skin turgor

overall elasticity and structural integrity of the skin

cleavage lines

lines in the skin that follow collagen fiber orientation and influence surgical incisions

fibroblast

connective tissue cell that produces collagen elastin and matrix in the dermis

collagen fibers

protein fibers that provide strength and support to the skin

lamellated corpuscle

alternate name for a Pacinian corpuscle

subcutaneous layer

layer beneath the skin composed primarily of areolar and adipose tissue; also called the hypodermis

fascia

connective tissue surrounding muscles and bones

adipose tissue

connective tissue specialized for fat storage

papilla of the hair

structure within the hair bulb containing blood vessels and nerve endings

growth stage

phase of the hair cycle during which hair length increases

regression stage

phase of the hair cycle during which hair growth stops and the follicle shrinks

resting stage

phase of the hair cycle during which hair is shed before a new cycle begins

lanugo

soft fine fetal hair

vellus hair

fine body hair present over much of the body

terminal hair

coarse pigmented hair found on the scalp eyebrows eyelashes and certain body regions after puberty

onychomycosis

fungal infection of the nail causing thick brittle yellow nails

ceruminous gland

modified sweat gland that produces earwax

cerumen

earwax produced by ceruminous and sebaceous glands

first-degree burn

superficial burn affecting only the epidermis