Cell types found here fibroblasts macrophages mast

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Cell types found here: fibroblasts, macrophages, mast cells and white blood cells It is a semi-fluid matrix that is heavily embedded with Collagen (which gives strength to the tissues) Elastin Reticular fibers
It is also richly supplied with Nerve fibers Blood vessels Lymphatic vessels Hair follicles Oil/sweat glands These components allow the dermis to be the source of nutrition that can make its way up to the upper layers. 1. Papillary layer (thin, superficial) a. Areolar connective tissue fibers that are wound with blood vessels b. The dermal papillae indent the epidermis, with their function of sensing touch and pain with nerve endings. They go further up to the edge of the skin, and are more prominent in areas where there is a lot of friction. c. Example: on palms of hands, soles of feet, dermal papillae form ridges that are known as friction ridges d. These friction ridges form a unique pattern which is the fingerprint 2. Reticular layer (thick, deep) a. Dense irregular connective tissue with thick bundles of collagen fibers parallel to the skin’s surface b. Collagen here gives strength and resilience to maintain hydration c. These lines are important in determining the direction for an incision, cutting in between layers will result in rapid healing and less scarring d. Stretch marks (striae): as the skin grows and stretching pressure increases, rips and tears in the skin result. e. Blister: repetitive rubbing causes the dermis to separate from the epidermis. The dermis therefore is traumatized and has an inflammatory reaction (fluid is released and builds up between the layers) f. Flexure lines: occur in places where there is frequent movement. The dermis is anchored down because of this so that the skin can move more easily. 3. Hypodermis a. A superficial fascia, subcutaneous tissue b. There is areolar connective tissue, blood vessels and adipose tissue c. Some amount of adipose tissue is useful for protection – it anchors the skin to underlying structures, absorbs shock, reduces heat loss Pigmentation in the skin 1. Melanin : the most important pigment, produced in the skin. Gives colours of yellow, rust, brown, black. The skin colour is dependent on the relative amount of other pigments. We all have the same levels of melanin, just with different activities. Those that live in areas with increased sun will have higher activities of melanin. Not enough sunlight in children does not activate calcium in growing children, which causes rickets (a disorder that causes the bones to curve)
2. Carotene : yellow/orange pigment that is acquired from plants 3. Hemoglobin : gives the skin a pinkish hue in fair skinned people. Cyanosis is when the skin has a blue tone as a result of deoxygenated blood (cases of low oxygen) 2.3: Accessory structures of the skin 1. Hair and hair follicles a. Function: i. Sense insects on the skin ii. Guard the head (trauma, heat loss, sun) iii. Shield the eyes, filter air b. The hair shaft: i. The medulla is the inner layer. It is composed of larger cells in is absent in fine hairs ii. The cortex

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