Andrews Flashcards
What are langers lines?
Also known as cleavage lines. Correspond to natural orientation of collagen fibers in dermis. Are perpendicular to orientation of underlying muscle fibers. Used to obtain most cosmetically appealing surgical scar-surgeon cuts in direction of Langers lines.
What are lines of
Blaschko?
They are skin lines invisible under normal conditions. They follow a V shape over the back, S shape over chest, stomach, sides, and wavy shape over head. Believed to trace migration of embryonic cells (epidermal cell migration)
What diseases are associated with the lines of Blaschko?
X-linked dominant-incontinenti pigmenti, CHILD syndrome, focal dermal hypo plasma, MLS syndrome
Inflammatory linear verrucous epidermal naevus, sebaceous naevus, hypomelanosis of Ito, McCune Albright Syndrome, segmental vitiligo
Linear lichen planus, linear cutaneous LE, lichen striatus, linear morphed
What diseases are associated with lines of cleavage?
PR, ashy dermatosis, MF, stage 2 syphilis, lesser trelat syndrome, exam thematic kaposi sarcoma
What is the meaning of centrifugal spread?
Moving outward from center
Meaning of centripedal spread?
Moving toward center of body
What is the average thickness of epidermis?
O.5mm
What types of collagen are present in the dermis?
Types 1,3,5
What type of sweat gland is attached to the pilosebaceous unit?
Aprocrine glands-coiled duct and straight duct
What type of sweat gland empties onto skin surface?
Eccrine gland; Has coiled duct followed by straight duct followed by spiral duct then acrosyringium
What are the four cell types in the epidermis?
Keratinocytes, melanocytes , Langerhans cells, Merkel cell
Describe the Langerhans cell
A dendritic cell of the skin and mucosa containing large granules called birbeck granules. They are scattered throughout the epidermis but are often seen in the stratum spinousum
Markers: CD1a***** S100, langerin
Secrete IL12**-this stimulates growth of T cells
What happens to the basal cells as they migrate upward towards the epidermis
Plasma membrane is replaced with cornfied cell envelope. They flatten and lose nuclei. Extrude cellular contents except for keratin and filaggrin (binds to keratin fibers in epithelial cells; become apart of lipid envelope in stratum corneum, thus playing a role in skin barrier function- blocks UVR and hydrates SC). Filaggrin will also release free amino acids in SC to assist in water retention.
Mutations in filaggrin are associated with what?
Ichthyosis vulgaris. Eczema
Where are the stem cell rich sites located in the epidermis
Rete ridges and hair bulge
Describe keratins
They make up type 1 and type 2 intermediate filaments, 30 different types, they are paired ( acidic and basic)
Type 1: acidic, K9-20, chromosome 17
Type 2: basic, K1-8, chromosome 12
What keratins are associated with basal layer?
5 & 14.
What keratins are supra basilar?
1&10.