Anatomy Exam #4 - Skin

integumentary system

skin, hair, nails, sebaceous gland, sweat glands (accessory structures)

function of integumentary system

- barrier

- protection

- termo regulation

- energy storage

-vitamin D synthesis

layers of the skin

epidermis and dermis (cutaneous layer), hypodermis (subcutaneous layer)

thin skin

Covers most of the body

Has four layers of keratinocytes

layers of thin skin

stratum basale, stratum spinosum, stratum granulosum, stratum corneum

thick skin

Covers the palms of the hands and soles of the feet

Has five layers of keratinocytes

layers of thick skin

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

stratum corneum

outermost layer of epidermis

- dead cells (15-30 layers)

- keratin protein

stratum lucidum

a layer of the epidermis found only in the thick skin

- eleian protein (makes it have a dark appearance)

- 1 layer

stratum granulosum

third layer of the epidermis

- 3 to 5 layers

- not dividing

stratum spinosum

fourth or third epidermis

- 7 to 10 layers

- active

- lesser degree of dividing

- produce keratohyaline (protein)

stratum basale

bottom layer of epidermis

- mitotically active cells

- 1 layer

- stem cells

keratinocyte

dying cells (alive on the bottom and dead on top layer)

what type of tissue is epidermis

stratified squamous epithelium

epidermal ridges

downward waves of epidermis

dermal papilla

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

layers of the dermis

papillary layer and reticular layer

epidermal ridge + dermal papilla

wave pattern

papillary dermis

areolar connective tissue

reticular dermis

dense irregular connective tissue

accessory structure

are in the dermis but are not made from that tissue...is made from the epidermal tissue

what is the dermis made up of?

connective tissue

What is the hypodermis made up of?

adipose tissue

langerhans cells

epidermal macrophages that help activate the immune system

melanocyte

cell in the basal layer that gives color to the skin

dendritic

shape of langerhan cells

epidermis function

- dry surface is unacceptable for growth of most microorganism

- langerhans cells are found in all but the stratum corneum

- antigen presenting cells (phagocytosis in foreign objects)

- first line of defense

factors affecting pigmentation

- type of melanin produced

- how much the malanosomes are filled with melanin gransules prior to transfer

- number of size of melanosome produced

- how long the melanosome persist in the keratinocytes

- degree of transfer within the dermis

how are melanocytes produced?

- melanocytes produce melanin from tyrosin in specialized organelles (melanosome)

- melanosome are transferred to keratinocytes upon stimulation

- melanosomes in keratinocytes contribute to skin's pigmentation

skin color

biological trait and polygenic trait

race

social construct

sources of vitamin D

- sunlight (7-dehydrocholesterol)

- steroid compound

- cholecalciferol (vitamin D)

- intermediary product (calcifediol) in liver

- calcitriol (calcium re-absorption) in kidney

- diietary cholecalciferol (calcium absorption) in digestive tract

free nerve ending

- found in epidermis

- sense pressure/pain/temp

tactile discs

- found on boarder between epidermis and dermis

- sense texture and pressure

meissner's corpuscles

- found in papillary dermis

- sense fine touch and vibration

lamellated corpuscles

- found in papillary dermis

- sense deep vibrations

ruffinin corpuscles

- found in reticular dermis

- sense stretch

thermoregulation of hot

-Sweat glands are activated

-No shivering

-Vasodilation (in dermis)

- muscle is relaxed

- heat loss by evaporation

thermoregulation of cold

-No sweat

-Shivering (muscle causes the hair to stand up)

-Vasoconstriction (in dermis)

hair follicles

- protection

- epithelial column

exocrine glands

- outside

- epithelial column

- sweat glands and sebaceous glands

nails

- protection

- nail field

hair shaft

visible part of the hair

hair follicle

a small tubular cavity containing the root of a hair

hair matrix

actively dividing area of the hair bulb that produces the hair

hair bulb

The rounded, club-shaped part of hair located at the end of the hair root

hair papilla

mass of connective tissue, blood capillaries, and nerve endings at the base of the hair follicle

arrector pili muscle

An involuntary muscle fiber attached to the underside & base of the hair follicle

sebaceous glands

secrete sebum (oil) into the hair follicles where the hair shafts pass through the dermis

parts of hair shaft (outside to inside)

- cuticle (hardest keratin)

- cortex (hard keratin)

- medulla (soft keratin)

stages of hair growth

-Anagen (Growth stage - active growth by nourishment from blood supply) (2-7 years)

-Catagen (Transition stage - detach from papilla) (10 days)

-Tetagen (Final resting stage - papilla shirk, angiogenesis, fall out of hair follicle) ( 3 months)

nail plate

hard part of the nail (hard keratin)

lunula

The half-moon-shaped, whitish area at the base of a nail

nail matrix

the part of the nail beneath the body and root from which the nail is produced

Eponychium

cuticle

Hyponychium

Skin between the free edge and fingertip of the natural nail

nail bed

skin underlying the nail plate (top layer of epithelia tissue)

Sebaceous (oil) glands

-Produce sebum to keep skin and hair soft, and prevent bacteria from growing on the skin

- prevent H20 loss

- anti bacateria

- holocrine secretion

merocrine sweat glands

- secrete a watery fluid directly onto the surface of the skin

- most common

- thermo regulation

apocrine sweat glands

- produce true sweat plus fatty substances and proteins; - found in the axillary (armpit) and anogenital areas of the body

sudoriferous glands

sweat glands

temperature control of body

negative feedback

burn

arrhythmia

first degree burn

epidermis

second degree burn

epidermis and papillary layer of dermis

third degree burn

epidermis, papillary and reticular dermis, and can be hypodermis is serve

rule of 9's

Head and neck = 9%,

Chest and upper back = 9% each

Arm = 9% each

Abdomen and lower back = 9 % each

Genital area - 1%

Leg - 18% each

pressure ulcers (1)

epidermis

pressure ulcers (2)

epidermis and dermis

pressure ulcers (3)

epidermis, dermis, and hypodermis

pressure ulcers (4)

epidermis, dermis, hypodermis, muscle, bone, superficial fascia

what does sebaceous glands cause?

acne

- whitehead (no opening)

- blackhead (opening to outside)

- papule (buildup)

- pustule (even more)

- cyst/nodule (goes down into bottom of follicle)

psoriasis

hyperactive disease (increased division in keratinocytes)

warts

hyperplasia and metaplasia

- can cause HPV infected cells

age

- fewer melanocytes

- drier epidermis (decrease in sebum)

- thinning of epidermis (ulcers)

- thinning of dermis (ulcers)

- diminished immune response (langerhan cells)

- decreased perspiration (sweat glands on/off)

- reduced blood supply

- fewer active follicles (less anagen)

- slower skin repair

- altered hair and fat distribution

eleidin

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

keratohyalin

granulated protein found in the stratum granulosum

hair cuticle

Outermost layer of hair; consisting of a single, overlapping layer of transparent, scale-like cells that look like shingles on a roof.

hair cortex

Middle, thickest portion of a hair shaft

hair medulla

innermost portion of a hair shaft

anagen

The period of active growth

catagen

The period of break down and change of hair growth

telogen

Resting phase of hair growth