the integumentary system

skin and appendages

the integumentary system includes

oil glands, sweat glands, hair, and nails

appendage types include

2.2

your skin measures __ square meters

15

your skin accounts for __% of your body weight

2

the skin is composed of __ distinct layers

epidermis

superifical layer of the skin

eipthelial cells

epidermis is made of

epidermis

outermost protective layer of the body and avascular

dermis

deeper layer of the skin

dermis

makes up most of the skin

dermis

made of connective tissue and vascular

subcutaneous layer

not part of the skin, considered deep to the skin

subcutaneous layer

also known as the hypodermis

subcutaneous tissue

made of adipose tissue

ketinocytes

90% of epidermal cells

keratinocytes

produce keratin: a protein that helps the epidermis protect from abrasions and remain waterproof

stratum basale

keratinocytes produced where

keratinocytes

gets pushed upwards by new cells beneath them, as they approach the surface they flatten and die

25-45

new epidermis every _____ days because you shed millions daily

friction

stimulates keratin production

langerhans cells

dendritic cells

langerhans cells

formed in the bone marrow and migrate to the stratum spinosum

langerhans cells

ingest foreign substances and activate our immune system

melanocytes

spider-shaped

melanocytes

produce melanin, a pigment that determines hair, skin, and eye color

similar

we all have ____ number of melanocytes

keratinocytes

melanin covers ____ to block from uv radiation

melanocytes

only found in the stratum basale

merkel cells

tactile epithelial cells

merkel cells

present at the junction between the epidermis and dermis

merkel cells

sense light touch

epidermis

composed of 5 layers

stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum basale

5 layers of the epidermis

stratum corneum

superficial epidermal layer, kertinocytes are dead

stratum corneum

20 to 30 layers of squamous, anucleate kertinocytes

3/4

stratum corneum thickness of the epidermis

stratum corneum

highly keratinized layer

stratum corneum

layer that protects from abrasion and waterproofs skin

stratum lucidum

clear layer

stratum lucidum

cells lose nuclei and die in this layer only found in thick skin

stratum granulosum

keratinocytes are living but begin to die in this layer

stratum grnaulosum

keratohyalin granules produced in this layer

lamellar bodies

lipids that waterproof our skin

stratum granulosum

lamellar bodies released in this layer

stratum spinosum

keratinocytes connected by desmosomes that make them appear shiny

stratum basale

deepest epidermal layer attached to the dermis

stratum basaale

single row of cells that rapidly undergo mitosis, create keratinocytes and push higher layers up

dermis

deeper layer of the skin, made of CT and broken into 2 layers

reticular layer

deeper, thick, bottom 4/5 layer of dermis

papillary layer

superficial, thin, top 1/5 layer of dermis

dermal papillae

skin nipples that bind epidermis and dermis together and create fingerprints

meissner’s corpuscles

sense light touch

capillary loops

where oxygen and nutrients are dropped in the dermis and where CO2 and waste leave the dermis

free nerve endings

sense pain, heat, cold, itch, and tickling

hair follicle

tunnel where hair grows from

arrector pili muscles

contracts to raise hair on end

sebaceous gland

oil gland

sebum

oil

sudoriferous gland

sweat glands

pacinian corpuscle

sense heavy pressure

adipose tissue

adheres skin to underlying muscle, insulates heat, and absorbs shock

sensory nerve

send messages from appendages to brain

motor nerve

send messages from brain to appendages

blood vessels

delivers blood to and from the skin

artery

drops off blood with oxygen and nutrients

vein

takes away blood with CO2 and waste

acid mantle

slows bacterial growth on skin

melanin

protects epidermal cells from uv radiation

evaporative cooling

sweat evaporates and pulls heat away from body

.5 L

sweat glands secrete __ of sweat per day

dilate

blood vessels __ and bring hot blood to the surface to release heat

contract

blood vessels ____ to pull blood vessels deep to trap heat

vitamin d

skin produce when exposed to uv rays

helps digestive tract absorb calcium

vitamin d advantages

rickets: weak bones

vitamin d deficiency causes

water, salt, pee

sweat contains

pili

another term for hair

hairshaft

made of dead, keratinized cells

shaft

part of the hair above the skin’s surface

root

part of the hair embedded in the skin

follicle

tunnel where hair grows from

shaft

texture of hair determined by shape of

round shaft

straight hair =

wavy hair

oval shaft

curly hair

flat shaft

body hair

sense insects on the skin

nose hair

filters particles in the air that we inhale

scalp hair

protect against heat loss and sunlight

eyelashes

shield the eyes form dust and dirt

male pattern baldness

genetic, more common in males, due to changes in testosterone

terminal hair

darker and thicker hair appearing in eyebrows, eyelashes, scalp, armpit and pubic region

vellus hair

peach fuzz on face, arms, legs, and stomach; meaning wool

nail matrix

thickened proximal portion of nail bed

eponychium

cuticle; layer of clear skin along bottom of nail

nail plate

nail body, the actual fingernail made of keratin

free edge

the nail tip, distal

nail fold

skin folds over the proximal and lateral borders of the nail

lunula

visible portion of the nail matrix, white crescent at bottom of nail

nail bed

pinkish colored soft tissue underneath nail plate

nail root

proximal part of nail embedded in the skin