Integument System Flashcards
Largest organ in body
Skin
Where is the thickest epidermis
Palms and soles
Thickest dermis
Back
Functions of the skin
Protection
Containment
Sensation
Temperature regulations
Stratum Corneum of the epidermis (1)
Most superficial 20-30 cells
Makes most of the thickness of epidermis
Cells are dead and flattened and always being replaced
Stratum lucidum (2)
Clear layer
Mostly keratinocytes
Only present in thick skin
Stratum granulosum(3)
3-5 layers of cells
Cells are starting to die
Waterproofing - lamellated granules
Toughness - keratohyalinegranules form keratin fibrils
Stratum spinosum (4)
Gets nourishment from the dermis
More division occurs here
Stratum basale (5)
Deepest layer of epidermis
Nourishment - vascular tissue in dermis
Contains stem cells that divide daughter cells and are pushed to the surface
Epidermis features
Avascular
Keratinized (keratin toughens skin ,keratinocytes age and produce keratin )
Contains melanocytes (produce dark pigment called melanin )
What percent of cells on epidermis are keratinocytes
90
How frequently is epidermis replaces
Every month
Dermis contains nerve endings for ?
Pain Pressure Touch Temp Vibration
What are the main structural components of dermis
Collagen
Elastin
Derail papillae
Collagen
Responsible for skins strength
How are collagen and elastin are laid down and why
Multi directionally , this allows them to respond to stretching and pulling without damage
Hypodermics (subcutaneous layer )
Loose CT
Contains adipocytes
Anchors dermis to muscle and bone
Cutaneous nerves ,arteries and veins supplying skin
Merocrine ( eccrine ) sweat glands
Connect to surface of skin by coiled duct
Deep in dermis
All most all over the surface of the body especially palms and soles
Apocrine sweat glands
Anchored deep In the dermis
Open into hair follicles
Location : armpit ,genital area ,nipples of the breast
Sebaceous glands
Most open into hair follicles
Can occur on hairless areas ( lips ,inside mouth )
Most numerous on face and scalp (produce sebum which lubricates scalp and hair )
Not found in soles and palms or the top of feet
Ceremonious glands
Modified sweat glands
Located in the ear canal
Arrector pili muscle
Can pul hair shaft into an upright position
Hair color
This is due to melanocytesin produced by the bulb of the hair follicle and then incorporated into the keratinocytes that form the hair
Explain these hair colors Dark Blonde or red Gray White
Dark - true melanin
Blonde / red - melanin that contains sulfur and iron
Gray - melanocytes age and lose the enzyme that produces melanin
White - air bubbles become incorporated into the growing hair
How does hair texture result
From the shale of the hair shaft
How does straight hair appear
Appears round in cross section
How does wavy hair appear in CS
Oval In shape
How does curly hair appear in cross section
Elliptical or kidney shaped
How do nails grow
Nails grow as epidermal cells below the nail root and transform into hard nail cells that accumulate at the base of the nail , pushing yhe rest of the nail forward
Where do nails come from
Stratum corneum
Lunula
Cuticle - white part that occurs because of the underlying epidermis that does not contain blood vessels
First degree burn portion (sunburn )
Epidermis
Second degree burn layers (blisters )
Epidermis and dermis
Third degree burn layers
Epidermis
Dermis
Subcutaneous layers
How does acne form (4 steps )
- hair follicle becomes blocked ( keratin contains dead cells )
- sebum is prevented from reaching the surface of the skin
- bacteria that normally live In the hair follicle break down the sebum behind the blockage
- thus produces chemicals that cause inflammation in the surrounding skin
Stretch marks
Occur with rapid size increase
Due to damage of collagen fibers in the dermis
Fade but never go away
