the skin and body membrane a&p

subcutaneous

just under the skin

IM

intramuscular

dermal/topical

on top of the skin

transdermal

patch put on skin

functions of tissues

cover and lubricate the body, line body cavities, form protective sheets around body organs

integument

the skin when it is considered as a body organ

integumentary system

the skin when it is considered as a body system

epidermis

outermost division of the skin

epidermis

consists entirely of stratified squamous epithelium

epidermis

consists of subdivisions which are represented by layers of cells making up the SSE

dermis

composed of connective tissue containing collagen and elastic protein fibers

collagen

braided long rope-like quaternary protein

hypodermis

subcutaneous layer or superficial fascia (not a division of the skin)

hypodermis

connects the dermis to underlying bones and muscles

hypodermis

composed of areolar and adipose connective tissues

keratinocytes

most cells of the epidermis

stratum germinativum/basale

germinating layer

stratum germinativum/basale

made up of cells attached to the basal lamina

stratum germinativum/basale

stem cells in layer; mitotically active; replace cells lost in the upper layers

layers of epidermis

stratum basale, spinosum, granulosum, lucidum, and corneum

stratum spinosum

spiny layer

stratum spinosum

consists of the next several layers of cells; cells begin to shrink; mitotic activity of the cells slows

stratum basale

most nourished of the epidermal layers because of nutrients diffusing from the dermis

stratum granulosum

granular layer

stratum granulosum

1-3 cell layers; mitotic activity stops

stratum granulosum

cells begin to manufacture the protein keratohyalin

stratum lucidum

clear layer

stratum lucidum

present only in thick skin (palms of hands; soles of feet)

stratum lucidum

keratohyalin leads to production of the protein eleidin

stratum lucidum

cells are densely packed and flattened, and do not contain nuclei

stratum corneum

horny layer

stratum corneum

outermost division of the epidemis

stratum corneum

20-30 cells layer thick; comprises about 75% of the epidermal thickness

stratum corneum

plasma membrane thicken- reduces permeability and water loss

stratum corneum

eleidin is converted to keratin- a very strong, waterproof protein

epidermal ridges

deep layers of the epidermis which extended into the dermis below

epidermal ridges

contain nerve receptors that provide sensitivity to change

melanocytes

pigment cells that are squeezed between the cells of the stratum germinativum

Merkel’s cells

large, oval cells located in the S. basale

Merkel’s cells

associated with touch; may have other functions; associated with a highly malignant skin tumor called the Merkel cell carcinoma

Langerhans cells

macrophages used in the body’s defense against microorganisms

Langerhans cells

located primarily in the S. spinosum

dermis

deep layer of skin

dermis

composed of connective tissue containing collagen and elastic protein fibers; contains blood vessels, nerve glands, and hair follicles

dermal regions

papillary region and reticular layer

papillary region

superficial region characterized by papillae

papillae

fingerlike projections located between the epidermal ridges

reticular layer

the deep layer of connective tissue that contains both collagen and elastic fibers

hypodermis

not a division of the skin

hypodermis

connects dermis to underlying bones and muscles

hypodermis

composed of areolar and adipose connective tissue

hair

consists of the fibrous protein, keratin

vellus

peach fuzz

intermediate

hair of the arms and legs

terminal

heavy, dark hair

lanugo

the very fine hair that covers a newborn infant- shed shortly after birth

shaft

the visible portion above the skin surface

root

portion below the skin surface

follicle

the socket which surrounds the hair; consists of stratified squamous epithelium

papilla

an indication at the bottom of the follicle; it contains blood vessels and nerves

bulb

an onion-shaped swelling located at the base of the hair

matrix

a layer of germ cells that produce new hairs

medulla

the soft, flexible center of the hair; contains soft keratin

cortex

a region of hard keratin that surrounds the medulla; gives the hair its stiffness

cuticle

a layer of hard keratin that coats the hair; gives texture

arrector pili muscle

smooth muscle in the dermis that is attached to both the hair follicle and skin; its contraction causes “goosebumps” and hair to stand up

cutaneous glands

all exocrine glands (sebaceous and sweat glands)

sebaceous gland

produce sebum

sebaceous gland

an oily substance that prevents excess water evaporation and keeps the skin soft and pliable

sudoriferous gland

secrete sweat/perspiration

insensible perspiration

water loss from interstitial fluids which evaporates into the air

sensible perspiration

produced by sweat glands

apocrine and eccrine

types of sudoriferous glands

apocrine gland

coiled, tubular glands that secrete a sticky, cloudy and potentially odorous perspiration into hair follicles

eccrine gland

merocrine gland

eccrine gland

distributed over entire skin; most numerous in palms of hands and soles of feet

eccrine gland

smaller than apocrine but, do not extend as far into the dermis; open directly to pores

eccrine gland

cools the surface of the skin to reduce body temperature; excretes water and electrolytes

nail

hard plates of tightly packed keratinized cells

body

the visible portion of the nail

root

An epidermal fold that is not visible from the surface

nail bed

the area of the epidermis covered by the nail body

eponychium

cuticle - a region of stratum corneum covering the nail body near the root

lunula

a pale crescent-shaped area near the root

hyponychium

an area of thickened stratum corneum beneath the free edge of the nail

nail matrix

thickened proximal are responsible for nail growth

thermoregulation

refers to the body’s ability to maintain a homeostatic balance between heat production and heat loss

hypothalamus

the body’s thermostat; maintain via heat loss and heat promoting mechanisms

heat promoting mechanisms

vasoconstriction, sweat glands close, and shivering

heat loss mechanisms

vasodilation and sweat glands open

reasons for burns

heat, radiation, electrical shock, and chemical agents

burn

destruction of skin cells

first degree burn

affects only the epidermis

second degree burn

affects epidermis and part of dermis

third degree burn

affects the epidermis and all the dermis, often also affects the hypodermis

wound

injuries that result in an internal or external break in the skin

incision

a clean, precise cut caused by knife or scalpel with no bleeding

laceration

similar to an incision, but with jagged edges with bleeding

abrasion

epidermis is rubbed or scraped away, exposing dermis with blood vessels

puncture

an object pierces the skin with little bleeding