integumentary accessory structures & friends

Hair

made mostly of keratin projecting from most skin surfaces

nonliving

hair papilla

have hair’s capillaries & nerves

hair matrix

have epithelial stem cells divide, push toward surface → keratinize

when does hair cells die

btwn papilla & surface

below the point is hair root & above the point is hair shaft

purpose of hair in nose and on eyes

filter incoming air

purpose of nerves of hair follicle

feel movement

cause of hair color

different amounts & types of pigment produced by melanocytes (at hair follicle)

white(air bubbles)

grey (decrease melanin)

eumelanin (black)—> Pheomelanin (blonde)

male baldness pattern

s3x link trait

hormone cause hair follicles to stop producing regular hair & producing shorter finer hair

alopecia areata

autoimmune disease- body attacks own cells

hair loss in some/all areas

Langerhans

Immune system

From red bone marrow

Merkel

Along the adjacent tactile discs

Rsponse to touch

earwax

secretion from ceruminous glands

sebum with dead epithelial cells

guard hairs, block particles, keep eardrum pliable, waterproof

nails

keratinized epidermal cells

protect tips of fingers and toes

nail root

produce nail

nail bed

have blood vessels = pink look

cuticle

stratum corneum that over laps part of nail

Tinea unguium

common fungal infection of the nails

onychomycosis

looks: white opaque, thickened, & brittle

risk ^ for: diabetes, small blood vessels diease, older women, fake nails

repair of integument

Bleeding

inflammation

proliferation

remodeling

scar tissue

repair of integument: bleeding

broken blood vessels in dermis

repair of integument: inflammation

trigger: mast cells → ^ blood flow = phagocytes attracted

phagocytes clean area of bacteria & other substances

repair of integument: proliferation

temp, blood clot/ scab stabilizes & protect wound

st. basale surround injured area

repair of integument: remodeling

fibroblasts arrive to make scar tissue

fills area underneath epidermis

repair of integument: scar tissue

made of collagen fibers, replaces damaged nerves, muscle cells, or glands

(cant remake those)

3 type of skin burns

1st degree: epidermis damages

look- red & swollen (Ex: sunburns)

2nd degree: epidermis & upper dermis damaged

look- red & blisters (ex: boiling water burns)

3rd degree: destroys all layers, nerves & blood vessels included

look- gray-white/ black

sagging & wrinkles causes

dehydration

age

Hormonal changes

uv exposure

stretch marks

thickened tissue from excessive stretching

skin fast & didnt have time to grow

aging affects

Epidermis: thins, stem cells activity & macrophages # declines = more injury & infections

vitamin D: production declines = reduced bone strength

melanin: less production = sensitive to UV light

sebaceous glands: activity declines = drier skin

Hair: follicles may stop producing/ produce finer hair

Dermis: elastic fibers → thinner = sagging & wrinkling (intensified by sun exposure)

wrinkling in water

after 30 min in water

keratinized cells in St. corneum absorb water & swell

deeper layers cells don’t swell = upper layers wrinkles upwards

Botox

neurotoxins produced by clostridium botulinum

blocks neurotransmitters that signals contraction of muscles in the skin

inject every 4-6 months

fungal infections

athlete’s ft, toenails fungus, ringworm caused by related species

spread by contact (in dark moist areas)

only treat by antifungal medications (ex: lamisil)

bacterial infections

impetigo, boils, and staph caused by species of bacteria (staphylococcus aureus) produces toxins

treat: antibiotics

transmitted: by contact

MRSA

strain staph, resistant to many antibiotics

viruses

cause chicken pox ,warts, & cold sores

Infect: epidermal cells, overgrowth & itching

airborne & direct contact

prevent: vaccination (difficult to treat)

itching

triggered by nerves firing when irritant lands on skin surface rubbed → dermis

Eczema

dermatitis

itchiness, red skin, rash

cause: immune system overreacting to substances that are normally not harmful

vitiligo

autoimmune disease

attacks melanocytes→ pigment in skin destroyed

can affect mucous membrane and eyes

white patches of skin appear on different parts of the body

albinism

congenital disorder characterized by complete/partial absence of pigment in hair, skin, and eyes

bruise

blood vessels in dermis break & leak blood into tissue

why result in bruising black and blue

hemoglobin & other cell components gradually break down & reabsorb

tattoos

inject ink droplets into dermis

dermis are more stable than epidermis

tactile (Meissner’s) corpuscle

in dermal papillae

dendrites wrapped in fluid filled capsule

respond to light touch

Deep lamellar (Pacinian) corpuscle

dendrite w/ concentric ring of cells

respond to deep pressure. vibration

free nerve ending

pain, temp

skin cancer

based on type of cells that grow uncontrollably

cause: overexposure to UV rays

basal cell carcinoma, squamous cell carcinoma, malignant melanoma

basal cell carcinoma

affect st.basale cells

least malignant & common type of skin cancer

squamous cell carcinoma

occurs in st.spinosum

tumors must be removed quickly

can metastasize through nearby lymph nodes & into rest of body

malignant melanoma

most dangerous

out of control growth in melanocytes

can metastasize quickly to blood & lymph vessels

how to tell malignant melanoma

A= asymmetry

• 2 sides of pigmented mole don’t match

B= border irregularity

• borders of mole are not smooth

C= color

• different colors in pigmented area

D= diameter

• spot is larger than 6mm in diameter

UV light pros and cons

harmful: skin cancer, break down folic acid(need for cell division)

Beneficial: stimulates vit. D synthesis

cyanosis

bluish tint

blood vessels near surface become extremely low in O2

Jaundice

buildup of bilirubin (byproduct of hemoglobin breakdown )

dark skin

produce greater quantities of melanin breaks down more slowly

melanin granules more spread out in keratinocytes and be seen throughout the epidermis

light skin

melanin clumped near keratinocyte nucleus

little melanin seen beyond st.basale

freckles

concentrated spots of melanin

carotene

orange-yellow pigment

can be converted to Vit.A

Rickets

vit.D deficiency

softening of bones

Vit.D

absorbption of calcium & phosphorus by intestines

psoriasis

skin disorder

skin cells of epidermis grow abnormally fast rate
replaced every 3-5 days instead of 28-30 days

abnormal growth triggered by triggered by inflammatory chemicals released by immune system cells

skin cells

takes 7-10 day to reach st. corneum and remain 2 weeks

4 components of homeostasis

homeostatic imbalance

receptor

control center

effector