Anatomy - Dermatology
cuticle
extension of stratum corneum of the epidermis over the base of nail
subserous fascia
fascia between musculoskeletal walls & serous membranes
investing fascia
fascia of invester muscles & nerves
albinism
a genetic defect in which you lack tyrosinase
bursae
fluid containing sacs
stratum lucidum
*found only in thick skin*, consists of a thin, translucent layer of flattened eosinophilic keratinocytes held together by desmosomes
cancer basal cell carcinoma squamous cell carcinoma
1/3 originate from the skin basal layer = spinous layer =
pilosebaceous unit
A hair follicle and its associated sebaceous glands make up a...?
Subcutaneous layer
Consists of *loose connective tissue* with pads of *adipocytes*. Binds the skin loosely to the underlying tissues and corresponds to the superficial fascia of gross anatomy.
yes, but dark-skinned individuals produce melanin more rapidly and accumulate them more abundantly
Do dark and light skinned individuals have the same amount of melanocytes?
stratum basale
Epidermal region involved in rapid cell division; most inferior epidermal layer
increases
Exposure to UV light increases or decreases production of melanin?
asynchronous
Is hair growth and shedding synchronous or asynchronous?
eumelanin
Melanin that give brown and black color to hair
nail bed
Portion of the living skin that supports the nail plate as it grows toward the free edge.
palms and soles
Sebaceous glands are embedded in the dermis over most of the body, except in the..?
arrector pili
Smooth muscles whose contractions force hairs to stand erect
False, We have few or no melanocytes
T/F. We have a lot of melanocytes at the palmar or plantar region
Dermis
The deep layer of the skin; composed primarily of dense, irregular connective tissue. *collagen* It also has loose connective tissue
hyponychium
The distal end of the plate becomes free of the nail bed at the epidermal fold called the...?
lubricate skin and hair
The function of sebaceous glands is to..?
nail body
The part of the nail that is visible. appears pink due to underlying blood capillaries.
nail root
The proximal part of the nail. Forms from the nail matrix in which cells divide, move distally, and become keratinized in a process somewhat similar to hair formation but without keratohyaline granules.
lamellated corpuscles
The receptors for deep pressure and high frequency in the dermis and subcutaneous tissue are ___.
nail plate
extends past finger or nail body
hair follicle
Tubelike depression in the skin in which a hair develops
anagen, catagen, and telogen
What are the three phases of hair growth?
retinoids
What class of acne medications can reduce sebaceous gland activity thereby reducing the formation of keratinized plugs?
melanocytes located in the hair bulb
What determines hair color?
stratum lucideum
What layer is missing from thin skin?
underneath
Where is the arrector pili muscle in relation to the sebaceous gland?
dermis layer, mostly damage of collagen fibers
Which skin layer are stretch marks found in?
intermuscular septa
_____ _____ are very thick fascia that separate one muscle group from another
sebum
a complex mixture of lipids that includes wax esters, squalene, cholesterol, and triglycerides that are hydrolyzed by bacterial enzymes after secretion. *Increases greatly at puberty*, stimulated primarily by testosterone in men and by ovarian and adrenal androgens in women
root hair plexuses
a web of sensory fibers surrounding the bases of hair follicles in the reticular dermis that detects movements of the hairs
tyrosinase
ability to synthesize melanin is dependent on the ability of melanocytes to produce what enzyme?
basement membrane
always occurs between the stratum basale and the dermis, and follows the contour of the interdigitations between these layers.
Carotene
an orange or red plant pigment found in carrots and many other plant structures. Precursor to vitamin A
five stratum layers
basal, spinosum, granulosum, lucidum, corneum
nail plate
bound to a bed of epidermis, the nail bed, which contains only the basal and spinous epidermal layers.
catagen
brief period of arrested growth and regression of the hair bulb?
langerhan's cells
cells found in the epidermis that are APCs.
hair papilla
connective tissue and a capillary loop that nourishes the hair follicle
stratum granulosum
consists of three to five layers of flattened cells, now undergoing the *terminal differentiation process* of keratinization.
lunula
crescent-shaped white area. mixture of opaque nail matrix and immature nail plate
Melanin
dark brown pigment in the skin that helps protect the skin by absorbing ultraviolet rays
deep fascia
dense, organized CT layers. DEEP to the skin. investing fascia, intermuscular septa, and subserous fascia
free edge
distal end of nail plate. the epidermal fold is underneath it.
hair
elongated keratinized structures that form within epidermal invaginations, the hair follicles
meissner's corpuscles
found in the papillary layer of the dermis and activated by light touch. also called tactile corpuscles.
papillary layer
free nerve endings, tactile receptors (meissner's corpuscles), and capillary loops are in what layer of the dermis?
third degree burn
full thickness burn and may ulcer and require skin grafting
nail matrix
germinal region of the nail plate
reticular layer
hair follicles, sudiferous glands, sebaceous glands, and sensory nerve endings are present in which layer of the dermis?
anagen
hair growth phase? long period of mitotic activity and growth
free nerve endings
in the papillary dermis and extending into lower epidermal layers, which respond primarily to high and low temperatures, pain, and itching, but also function as tactile receptors
Papillary layer
includes the dermal papillae, consists of loose (areolar) connective tissue, with types I and III collagen fibers, fibroblasts and scattered mast cells, dendritic cells, and leukocytes
epidermal ridges
increase friction, provide better gripping surface, causes fingerprints. caused by epidermis invaginating into the dermis *between the dermal papillae*
psoriasis
increased keratinization/thickening of the epidermis due to overactive T lymphocytes which triggers autoimmune reaction to the skin
four different layers of the epidermis
keratinocytes, melanocytes, merkel's cells, langerhan's cells
basal layer
location of melanocytes
telogen
long period of inactivity during which hair must be shed
friction blister
lymph filled space between the epidermis and the dermis of the thick skin. created by excessive rubbing of ill-fitting shoes
eponychium
medical term for cuticle
ceruminous glands
modified APOCRINE glands in external auditory canal that secrete ear wax to prevent foreign bodies from entering the ear
reticular layer
much thicker, consists of dense irregular connective tissue (mainly bundles of type I collagen), with more fibers and fewer cells than the other layer of the dermis
stratum corneum
outermost layer of the epidermis, which consists of flattened, *keratinized cells*. These fully keratinized or cornified cells called squames are *continuously shed at the epidermal surface* as the desmosomes and lipid-rich cell envelopes break down
nail root
portion buried in fold of skin at base of the nail. as it hardens it becomes the nail plate
fascial planes
potential spaces between adjacent fascias or fascia-lined structures
corns and calluses
protective thickening/hardening of the cornified epidermal layers, can occur with continued rubbing
light-skinned and sun exposure
risk factors for skin cancer
first degree burn
superficial burn in which the epidermis is injured
second degree burn
superficial, partial-thickness burn. may blister and can take weeks to heal and scar.
eccrine sweat glands
sweat glands that empty their secretion onto the skin surface via sweat pores
apocrine sweat glands
sweat glands that secrete a more protein-rich sweat into the follicles of hair in skin of the axillae and perineum
merkel's cells
tactile cells -sensory receptors for fine pressure (ex blowing air onto arm)
line of cleavage
tension lines that show predominant orientation of collagen fiber bundles
subQ, subfascial, and subtendinous
types of bursae
stratum spinosum
typically the thickest layer of keratinocytes. They are held together by desmosomes
holds tendons in place during movement
what do retinacula do?
stratum corneum and fatty areas of dermis and hypodermis
where is vitamin A found
increased UV radiation, they don't produce as much melanin
why is melanoma more predominant in lighter skinned individuals
translucent
without melanin and carotene the skin appears...?