Skin Anatomy and Physiology Lecture Powerpoint Flashcards
mostly review, a little new
What layer of epidermis contains melanocytes?
Stratum basale
What type of sudoriferous glands produce watery sweat?
Eccrine glands
Keratinocytes definition
Skin cells, the most common cell type in the epidermis composing the superficial layer of skin
What type of epithelium is the epidermis composed of?
Keratanized stratified squamous epithelium
2nd most common type of cell in epidermis
Melanocytes
The epidermis vs dermis vs hypodermis vascularity
The epidermis is avascular and relies on the vascular dermis to supply it, the hypodermis is even more vascular
Langerhan’s cells definition
Specialized epidermal cells that function immunologically
Merkel’s cells definition
Specialized epidermal cells that function to provide somatosensory function (light touch and discrimation)
Melanocytes definition
A specialized type of epidermal cells that function to produce melanin pigmentation in the skin
5 layers of epidermis from base up
- stratum basale (germinativum)
- stratum spinosum
- stratum granulosum
- stratum lucidum
- stratum corneum
Statum basale
Innermost layer of epidermis consisting of single row of columnar stem cells (basal cells) that divide to form keratinocytes for stratum spinosum
Stratum spinosum
2nd deepest layer of epidermis composed of keratinocytes with sharp shapes forming bridges between each other
Stratum granulosum
3rd deepest layer of epidermis composed of cells that flatten and form granules in the cytopalsm creating a water proof barrier of the skin
Stratum lucidum
4th deepest layer of epidermis composed of thin layer of dead cells to reduce friction on thick skin
Stratum corneum
Most superficial layer of epidermis compsed of flat dead cells that shed biweekly
2 layers of the dermis and their characteristics
1) Papillary dermis - thin layers of collagen popping into the epidermis
2) Reticular dermis - deep, dense, irregular collagen
4 things that arise from the dermis
- hair follicles
- erector pili muscles
- sebaceous glands
- sudoriferous glands
Sebaceous glands
Glands associated with hair follicles that secrete oil onto hair surface
Eccrine (merocrine) sweat glands, what stimulation are they from sympathetic NS?
Produce watery sweat not associated with hair follicles all around the body stimulated by heat and cholinergic SANS stimulation
Apocrine sweat glands, what stimulation are they from sympathetic NS?
Thick milky sweat glands that leads to extensive odor and is concentrated in axilla, perianal and genital regiions, associated with hair follicles and activated by adrenergic SANS from stress or sex stimulation
Dermis and blood shunting
When body is hot, vasodilation occurs shunting blood to the skin surface to lose heat to surrounding area, and inverse in the cold
Meissner’s and Vater pacini corpuscles
Specialized nervee cells that transmit sensations of touch and pressure via mechanoreceptors found in the dermis
Histiocytes
Wantering macrophages of the dermis
Mast cells location and function
Primarily located in the dermis around blood vessels, manufacture and release histamine
Hypodermis
Connection area between skin and underlying fascia, houses larger blood vessels and nerves,, and plays a pprominent role in regulation of temp of the skin
When getting a skin biopsy, it is important to get…..
….all the layers down to the subQ tissue to determine how deep the lesion has invaded into other tissue
3 major funcitons of skin
- barrier against environment
- barrier against water loss
- fluid and temp regulation
Progression of diabetic ulceration injury
- Shooting or sharp burning pain in the foot due to decreased blood supply to the nerves
- loss of sensation completely (nerve death)
- cannot sense ulceration injury
4 phases of skin injury repair
- coagulation
- inflammation
- proliferation
- remodeling
Epidermopoiesis definition and what stimulates it and inhibits it?
The process by which new skin cells are produced
Stimulated by androgens and vit A
(topical retinoids)
Inhibited by glucocorticoids (steroids to treat psoriasis and eczema)
What causes greasy hair?
Sebaceoous gland secretion onto hair shaft
Hair matrix
Group of rapidly mitotic cells that lie deep in the dermis to form the hair shaft, has nervous sensation and is thus painfult o pull
Hair shaft
The hair proper, composed of dead protein resulting in no nervous ssensation when cut
Terminal airs
Thick pigmented hair that is androgen sensitive!!!!
Vellus hairs
Short, fine, nonpigmented hair that covers much of the body and is not androgen dependant
Lanugo hairs
Fine hair found on the fetus and some anorexics normally shed and replaced with vellus hair within months
The sensation of a hair being stimulated is different from…
….the nerves that detect light touch on skin
Random growth pattern of human hair
Refers to the fact that human hair does not grow cyclically or seasonally but terminal hair is influence by androgens and reaches a definitive lenght before being shed and replaced by new hair
Anagen stage
Stage of active hair growth
Catagen stage
Transitional stage from active growth to cessation
Telogen stage
Stage of hair growth cessation and beginning of shedding, once completed returns to anagen stage
Nail root
Germinal atrix beneath skin in proximal portion of fingernail and extending into base of nail, the source of proliferatiion
Lunula
Crecent shaped dome at base of nail
Nail bed
Flesh beneath nail, contains blood vessels, nerves, and melanocytes (can still get melanoma!)
Nail plate
Actual fingernail, made of transulcentt keratin
Eponychium
Cuticle, skin of the finger and the fusing of that with the nail to provide a wataerproof barrier at the base of the nail
Paronychium
Lateral nail folds, skin that lies over the nail plate on its sides
Hyponychium
Area between nail plate and fingertip, provides waterproof barrier for nail
