Skin Flashcards
__________ is the outer layer of skin and is derived from ectoderm
Epidermis
_________ is the inner layer of skin and is derived from mesoderm
Dermis
_______ lies is a part of the tegument that lies beneath the two skin layers and is fatty CT (GA: superficial fascia)
Hypodermis
Thin (hairy) skin and thick (hairless) skin refer only to the thickness of the ___________
epidermis
Thick skin has ___________ which give finger and foot prints
papillary ridges
The main cell type of epidermis
Keratinocyte
Lowest layer of epidermis, cuboidal
Stratum basale
________ tie keratin networks to membrane and to neighboring cells
Desmosomes
______________ is caused by a mutation in keratin expressed in basal cells of the epidermis
Epidermolysis Bullosa Simplex
Autoimmune blistering disease - attack on desmosomal proteins
Pemphigus
Layer of epidermis that has several layers just above the stratum basale, below stratum granulosum
Stratum spinosum
Layer that has keratohyalin granules containing fillagrin, outer apical surfaces have lamellar bodies
Stratum granulosum
____________ in between stratum granulosum and stratum corneum are hydrophobic and form a barrier to water to prevent dehydration
Lamellar bodies
At least several layers of keratin, dead cells
Stratum corneum
Corneocytes detach from the stratum corner due to decreasing pH and proteolysis of __________
desmosomes
___________ are derived from neural crest cells and invade the stratum basale with processes (melanosomes) that are filled with melanin and are phagocytosed/endocytosed by keratinocytes
Melanocytes
__________ is the layer of epidermis with the most melanin because the cells are constantly dividing, so the DNA needs to be protected the most from UV (melanin caps the tops of nuclei)
Stratum basale
Type of melanin that stains brown
Eumelanin
Type of melanin that looks red
Pheomelanin
______________ is the thickest layer of epidermis, so Langerhan’s cells are often found there
Stratum spinosum
Layer of epidermis where basal cell carcinoma occurs (common, hardly ever metastasizes)
Stratum basale
Cells involved in squamous cell carcinoma (common, metastasis not common)
Keratinocytes
Cells involved in malignant melanoma (~15% metastasize) - derived from neural crest cells, job is to invade surrounding tissues
Melanocytes
ABCD of melanoma
Asymmetry of mole
Border - uneven/raised
Color - uneven
Diameter greater than 6 mm
__________ expression increased during tanning (analgesia, dependency) that may be involved in tanning addition
Controlled along with increased pigment production
Beta-endorphin
DICT underneath epidermis
Dermis
_________ contain capillaries and nerve endings and serve to increase surface area and binding between epidermis and dermis
Dermal papillae
2 layers of dermis
Papillary
Reticular
Upper (outer) layer of dermis with finer collagen
Papillary
Lower (inner) layer of dermis with thicker collagen (collagen determines Langer’s lines which is then where skin splits - helps determine where to cut to get less scarring)
Reticular
_______ is a network of blood vessels (capillaries for capillaries) - important for thermoregulation
Plexus
_____ nerve endings = end of axon
Free nerve endings
_________ nerve endings connect with stratum basale and are important for sensing texture
Merkel’s
________ are important for touch and can be found concentrated in fingertips
Nerve endings
Huge nerve endings important for sensing vibration, multilayered capsule of Schwann cells, fluid, and layers of CT (properties of capsule determines what it responds to) looks like an onion cut in half
Pacinian Corpuscles
Nerve endings important for movement of objects against skin, axon winds through capsule and Schwann cells (doesn’t have fluid or layers) - looks like wrappings of a mummy
Elongated, near stratum basale of epidermis
Meissner’s Corpuscles
Epidermal appendages are derived from the ______
epidermis
Very large epidermal appendages in which cells derived from the epithelium surround hair and fill with keratin
Hair follicles
__________ muscle attached to hair follicle and connected to dermis that is responsible for raising hairs and goosebumps
Arrector Pili Muscle
Stem cells of the ______ of hair follicles are used to repopulate epidermis, hair follicles, and sebaceous glands during wounding
bulge
During normal homeostasis, ________ cells maintain epidermis, and bulge cells maintain follicle (sebaceous gland stem cells too)
basal cells
Hair cycle (make a hair, resting period, falls out, make new hair) occurs in ___________, a source or stem cells
Hair follicles
__________ secrete sebum: triglycerides fatty acids, waxes (oil of skin)
Sebocytes
A pore is _______ coming from a hair follicle
sebum
The sebaceous glands have ___________ cuboidal epithelium
stratified
Sebaceous glands use _________ excretion, where the whole cell is excreted (cells differentiate and die)
holocrine
__________ have lacy cytoplasm and secrete sebum
Sebaceous glands
___________ sweat glands use merocrine excretion to secrete a mixture of carbs, lipids, proteins, and ammonia (secrete in response to emotional stimuli)
Apocrine sweat glands
Coiled tube sometimes associated with hair follicles. Only located in certain parts of the body (smelly - anus, external genitalia), contains pheromones in animals - bacteria act on the sweat to cause the odor
Apocrine sweat glands
_____________ cells can contract to squeeze out sweat
Myoepithelial cells
Simple cuboidal or columnar secretory cells and myoepithelial cells, ducts are stratified cuboidal
Ceruminous glands of ear (ear wax)
Glands of Moll of eyelashes - antibacterial
Apocrine sweat glands
Merocrine glands that secrete sweat in response to increased body temperature or emotional stress, saltwater secretion (typical sweat) contains water, salt, lactate, urea, ammonia
Small lumen, see both gland and duct
Duct is darker staining and stratified cuboidal
Eccrine sweat glands
Not part of skin, but is part of integument
Can have appendages that sit here
Fatty CT
Hypodermis
