oxyhemoglobin in dilating arteries/capillaries ex. DERMATITIS (skin infection) in the papillary layer, the plasma cells/blood vessels get leaky to fight off infection, and you see a skin coloration on the surface; ex. ERYTHEMA which is an acute dilation of blood vessels; the chronic form is ROSACEA which is constantly dilated blood vessels, so one looks like they are constantly blushing Bluish Tint: dexoyhemoglobin in veins (note blood is NEVER blue, its bright red if it is oxygenated, and dark red if it’s deoxygenated) ex. CYANOSIS which is a bluish tinge in fingers, toes, or lips (characteristic of pulmonary disorder) Yellow Tint: due to a liver disorder (JAUNDICE), it could be a hepatitis issue – the liver is supposed to breakdown bad hemoglobin into BILLY RUBIN, however if there is a disorder there is a buildup of Billy Rubin, called HYPERBILIRUBINEMIA, which gives a yellow color – a baby with Jaundice is usually put in a billi-blanket/light that converts the billy rubin into something that can be easily excreted from the body Multiple Colors: TATTOO – we don’t really know how it stays in the skin, but we do know that it accumulates in the PAPILLARY LAYER of the DERMIS Dermal Circulation & Innervation The Dermal Blood Supply: blood vessels are located deep down in the dermis are called the SUBCUTANEOUS PLEXUS, they are located at the DERMAL/HYPODERMAL border The Sub-Q Plexus vessels run up into the papillary layer and form the PAPILLARY PLEXUS, which give rise to capillaries in the Dermal Papillae (these allow for temperature regulation and epithelial nourishment) A CONTUSION (aka BRUISE) is the rupture of the Dermal Blood Vessels SUBCUTANEOUS LAYER (aka HYPODERMIS or SUPERFICIAL FASICA) This is NOT a region of the skin, rather a region beneath the skin; it helps position the skin relative to underlying, muscle, tissue, but still allows form independent movement/sliding of TWO upper layers (so epidermis & dermis can slide relative to muscle beneath because the hypodermis) Adipose also functions as an energy reserve, shock absorber, and thermal body blanket This layer is made up of ADIPOSE CT and is loaded with blood vessels that branch up into small capillaries into the dermis Help nourish lower layers of EPIDERMIS (as they are avascular) and control vaso-dilation/constriction The fact it’s loaded with blood vessels makes it a desirable site for SUB-Q Injections, as they would be readily absorbed into blood & there is nothing in this layer to muck up/damage Note: We are born with a FIXED amount of ADIPOSE CELLS (however it has been observed that a HUGE Adipocyte can split and a fibroblast can become an adipoctye, but rarely) – either way LIPOSUCTION permanent weight loss because you are removing fat cells that cannot replace themselves However, fat cells store toxins and if there are no cells to store them in, where will they accumulate?
Accessory Structures in the Skin
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