Integument Flashcards
Thin Skin
covers most of body surface. Contains hair follicles, sebaceous glands, sweat glands, and erector pilae muscles
Thick skin
covers palms of hands and soles of feet. No sebaceous glands or erector pilae muscles, but have sweat glands
Epidermis of skin
made of stratified squamous keratinized epithelium
Dermis is made of
Loose CT and dense irregular collagenous CT
Cell types found in the epidermis
keratinocytes (most common) and non-keratinocytes
Epidermal ridges
folds in the epidermis that extend down into the dermis.
dermal pailla
projections coming from the dermis into the epidermis
basal cells in epidermis
founder where epidermis meets dermis
area of intense mitotic activity
What happens as cells migrate from stratum basale to surface of skin
acquire more keratin, become keratinized, die and slough off.
langerhans cells
defensive cells. provide protection against invading antigens. Derived from bone marrow precuses. Reside in all layers of epidermis, but mostly in stratum spinosum
Merkel Cells
mechanoreceptors. Found in base of hair follicles and fingertips. Attach to keratinocytes by desmosomes. Specifically found in stratum basal and makes merkel cell-neurite complexes
Melanocytes
protect skin from UV radiation. Arise from neural crest. synthesize melanin. Located in stratum basale and superficial dermis
How to tell if it’s a langerhan cell
pale cytoplasm, looks like halo around cells
Birbeck granules
look kind of like a tennis racket. Found in Langerhans cells. Function not understood
What do melanocytes synthesize besides melanin?
tyrosinase, which turns tyrosine into melanin.
Melanin Granule
melanosome that has melanin in it. Is dark. Ends up in cytoplasmic processes
Is there a difference in the total number of melanocytes in different races?
no
What is pigmentation of skin due to?
tyrosinase activity, number of melanin granules, size of melanin granules, distrubution of melanin granules, rate of breakdown
Where is the distribution of melanocytes in lighter skin people
more in nucleus
Does dark skin break down faster or slower?
slower
Factors that contribute to diagnosis of malignant Melanoma
Appearance Border Color Diameter Evolution
What are the layers of thick skin from bottom to top
Stratum Basale Stratum Spinosum Stratum Granulosum Stratum Lucidum Stratum Comeum
Stratum Basale
single layer of columnar cells. Anchors dermis to epidermis. Important in cell renewal
Basal Cell Carcinoma
often due to chronic sun exposure. Has pearly papule, rarely metastasizes.
Stratum Spinosum
Have railroad tracks, which are intercellular bridges between neighboring cells. Gives strength to cell, protects against microorganisms
Stratum Granulosum
Contains 3 or 4 layers. Has frgmented nuclei. DNA is breaking down. Has keratohyalin granules and membrane-coating granules
Keratohylin Granules
contain keratohyalin (soft protein)
Membrane-coating granules
release lipid to extracellular space. Lipid makes sheets of waterproof materal.
Stratum Lucidum
allows light to go through. Contains only dead cellular material, no cytoplasm or organelle.
Stratum corneum
very thick. Layer of dead cellular material. has lots of keratin
What layers are way smaller in thin skin not have the compared to thick skin
stratum lucidum and stratum granulosum
Ichthyosis
excessive keratin buildup. Results in fish like scales
Papillary layer of dermis
most superficial layer. Made of loose CT
Which areas have prominent epidermal ridges, dermal papillae, and dermal ridges
areas subject to increased mechanical stress (palms and soles)
Reticular layer of dermis
provides tensile strength, has many collagen bundles, also contains some elastic fibers
Dermis
contains ducts of sweat glands, portions of hair follicles, sebaceous glands
Hypodermis
layer underneath the dermis. contains some adipose tissue. not part of skin
Free nerve endings
detect pain and temperature
Pacinian Corpuscles
detect pressure, vibration
Meissner’s Corpuscles
mechanoreceptors for discriminatory, fine touch
Eccrine sweat glands
Have myoepithelial cells which assist in expulsion of sweat from secretory unit. Innervated by post-ganglionic sympathetic fibers. Simple coiled tubular gland
Apocrine sweat gland
found in axilla, areola of nipple and in anal region. A merocrine gland. Innervated by the sympathetic nervous system. Produces large amounts of sweat
Sebaeous glands
oil producing glands. Induced by hormones, holocrine secretion.
Hair bulb
at base of hair follicle. encloses dermal papilla.
Medulla of hair follicle
moderate keritinization (pink)
cortex of hair follicle
keratinized (purple)
curticle
keratinized (dark band,
Interal root sheath
some keratinization
External root sheath
not part of hair
glassy membrane
acts like a basement membrane
Arrector Pili Muscle
smooth muscle. Attaches to hair follicle midway, obliquely. raises the hair
Nail plate
dense keratinized plate. rests on nail bed
Nail matrix
epithelium under nail root. Growth occurs here
