BIOL-3150 Lecture Notes - Lecture 17: Parallel Array, Sebaceous Gland, Keratinocyte
16 May 2019
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Classified as thin or thick skin, based on number of strata in the epidermis. Thick thickness based on the number of strata: contains 5 layers, found on palms of hands, soles of feet & corresponding surfaces of fingers & toes, observe sweat glands but not hair follicles or sebaceous glands. Arise from melanin being expressed by keratinocytes (produced by melanocytes: ranges in color from yellow, reddish, tan, brown & black. Carotene yellow-orange: acquired via diet, accumulates in keratinocytes. Localized areas of excessive melanocyte activity (because freckles can come and go) hemangioma. This may disappear over time or may be surgically removed. harmless. Due to proliferation of blood vessels that form a benign tumor. Many of these are displayed as birthmarks. friction ridges. Formed by large folds/valleys of both dermal & epidermal tissue. Function - helps with grasp. the sweat that arises on these ridges helps produce friction so you can grab things. ridges form finger prints.
