unit 2 terms

tissue

group of similar cells performing a common function

histology

study of tissues

four primary tissue types

epithelial, connective, muscle, nervous

epithelial tissue

covers surfaces, lines cavities, forms glands

apical surface

free surface of epithelial tissue

basal surface

bottom surface attached to basement membrane

basement membrane

anchors epithelium to connective tissue

avascular

lacks blood vessels

polarity

structural difference between apical and basal surfaces

protection

guards underlying tissues

absorption

moves substances into cells

filtration

passage of small molecules

secretion

production of substances (glands)

simple squamous epithelium

thin; allows diffusion (alveoli, capillaries)

simple cuboidal epithelium

secretion & absorption (kidney tubules)

simple columnar epithelium

absorption/secretion (digestive tract)

pseudostratified columnar epithelium

appears layered; often ciliated (trachea)

stratified squamous epithelium

protection from abrasion

keratinized epithelium

dry, tough, waterproof (skin)

nonkeratinized epithelium

moist surfaces (mouth, vagina)

connective tissue

supports, protects, binds tissues

extracellular matrix

nonliving material between cells

ground substance

gel-like background material

collagen fibers

tensile strength

elastic fibers

stretch and recoil

reticular fibers

supportive network (lymphoid organs)

areolar tissue

cushions organs; holds tissue fluid

adipose tissue

fat storage, insulation, cushioning

reticular tissue

forms stroma of lymph organs

dense regular connective tissue

parallel fibers (tendons, ligaments)

dense irregular connective tissue

irregular fibers (dermis)

dense elastic connective tissue

stretchy support (arteries)

hyaline cartilage

support; reduces friction (trachea, joints)

elastic cartilage

flexible support (ear)

fibrocartilage

shock absorption (intervertebral discs)

cutaneous membrane

skin

mucous membrane

lines cavities open to exterior

serous membrane

lines closed cavities

synovial membrane

produces joint fluid

integumentary system

skin, hair, nails, glands

epidermis

outer epithelial layer

dermis

connective tissue layer beneath epidermis

hypodermis

subcutaneous layer; adipose & areolar tissue

stratum basale

mitotic stem cells

stratum spinosum

desmosomes provide strength

stratum granulosum

keratin formation begins

stratum lucidum

only in think skin

stratum corneum

dead, keratinized cells

keratinocytes

produce keratin

melanocytes

produce melanin

melanin

pigment protecting against UV

carotene

yellow-orange pigment

hemoglobin

red pigment in blood

physical barrier

blocks pathogens and water loss

chemical barrier

antimicrobial secretions

biological barrier

immune cells (macrophages, dendritic cells)

thermoregulation

temperature control

perspiration

sweat cooling mechanism

hair shaft

visible hair

hair follicle

produces hair

arrector pili muscle

causes goosebumps

sebaceous glands

oil (sebum) secretion

eccrine glands

sweat glands

nail matrix

produces nail cells

nail plate

hard nail surface

eponychium

cuticle

mole (nevus)

pigmented skin lesion

vitiligo

loss of melanocytes

albinism

reduced melanin production

melanoma

malignant skin cancer

ABCD rule

asymmetry, border, color, diameter

first-degree burn

epidermis only

second-degree burn

epidermis + dermis

third-degree burn

full thickness destruction