ch 3 Flashcards
layer of skin, top to bottom
epidermis
dermis
hypodermis
epidermis
Avascular, no direct blood vessel supply
Keratinizedsquamous epithelium
- keratinocytes, melanocytes, merkel cells, langerhans cells
Keratinocytes
(tough, carry melanin granules)
□ The main ingredient in these cells iskeratinprotein, manufactures and stores the protein
□ Stratified
□ When we are exposed to sun we contain more melanin taken up by the keratinocytes
Freckles are caused by keratinocytes taking in more melanin
melanocytes
(colour granules, UV protection)
□ Produce melanin, 8% of the cells are melanocyts, dont contain the melanin.
□ Bottom layer of the epidermis
□ Moles are exagerated growths of melanocytes, highly regenerated cells
merkel cells
(sensory)
Attached to the epidermis, bottom layer
langerhans cell
(macrophages)
□ Part of immune system
5 layers of epidermis
(stratum spinosum)
basale spinosum granulosum lucidum corneum
basale
(deep)
Furthest away from external environment
spinosum
(spider)
□ Alive layer, contains Langehans cells
□ Dehydrated but still attached
□ Little replication
granulosum
(water proofing, last area of oxygenation…too far)
□ Oxygen would be used up and the cells start to die, release a substance makes it a hydrophobic barrier
Glycolipidis released
lucidum
(thick skin, dead)
□ Just above the granlosum
corneum
(dead but horny (cornified) cells) You will sluff off lots during your lifetime!
□ Dead cells, thick layer of just dead cells.
dermis
○ Wavelike appearance, to increase surface area for blood vessels § Leather is made from dermis layer ○ Connective tissue cells ○ Nerve fibers ○ Blood vessels
2 layers of dermis
§ Papillary 20%
§ Reticular 80%
Tattoos go into the reticular region.
hypodermis
Not a part of the integumentary system, comprised of fat.
Hypo = low or below…below the Dermis
- Sometimes calledsubcutaneouslayer
Insulates the body, allows movement, jellylike, between the skin and the muscle
hypodermis
○ Formed by areolar and adipose tissue
§ Adiposepredominates
§ Allows movement of muscle tissue below
§ The site of subcutaneous FAT (different b/w sexes)
§ Females store fat in hip region, males in abdominal region
skin colour
Pigments from melanin, carotene and hemoglobin
melanin
○ Precursor:tyrosine
§ Ranges from yellow-red-brown-black
§ Freckles/moles are localized melanin
§ Vitiligo
§ Albinism
□ Lose the ability to produce melanin
○ Eumalaninandpheomelanin
§ Eumelanin is yellow to red
Pheomelanin is darker
carotene
○ Yellow-orange from veggies
accumulates in stratum corneum and fat of hypodermis
hemoglobin
○ O2 carrying part of RBC
Where ever there are capillaries there’s hemoglobin!
Gives skin pinkish hue when you blush…if you blush!
birthmark
- areas of skin with too many capillaries
skin appendages
Hair
○ dead keratinized cells secreted from the living hair follicle
Sebaceous glands(grease)
○ secrete sebum which protects and conditions the skin
Sweat glands
○ secrete sweat (a blood filtrate) which is mostly water (99%)
Nails
○ scale-like modification of the epidermis - the human equivalent to a hoof!
- Act as a brace to add strength to our finger tips
burns
- Causes rapid fluid loss and reduced blood flow
- Infection risk is high
first, second, third degree
first degree burn
○ Epidermis only
○ Sun burn, UV rays
second degree burn
○ Destruction of tissue in the dermis
○ Blisters are often at the level of second degree and worse
○ Lots of vessels, sweat glands, leading to fluid loss
○ Concern for infection, because epithilial is there to protect the vessels.
3rd degree burn
○ No protection
○ Blackening of tissue
○ Lost the abilitiy to repair the region because vessels are destroyed, fluid loss, severe risk of infection.
cancer of epithelia
(Carcinoma)
- Fastest growing cancer in western hemisphere
- Name of carcinoma refers to “where” abnormal cell growth occurs
basal, squamous, melanoma
basal cell
Karitinocytes, localised, not involving the melanocytes
squamous cell
○ In stratus spinosum
○ Benign, localized
melanoma
○ Localized to basal layer but involve melanocytes.
○ (4mm in size might be too late)
○ Asymmetrical
○ Often becomes malignant
