The Integumentary, Skeletal and Muscular Systems
Psoriasis is a chronic skin disease in which afflicted individuals develop red patches with a scale-like appearance. The cause of psoriasis is a relatively simple one, but it is difficult to treat. The epidermal cells of an individual with psoriasis are dividing 5-10 times more frequently than they should be! This accounts for the excessive accumulation of cells that leads to the symptoms, as they cannot be sloughed off quickly enough to prevent buildup.
Which of the following statements is true of the cells making up the scaly patches of a psoriasis sufferer?
|A||The cells are alive and contain large quantities of melanin.|
|B||The cells are dead and highly keratinized.|
|C||The dells are far from the dermis, but blood vessels from the dermis grow towards the surface of the skin and supply them with nutrients, or else they could not continue to divide.|
|D|| The cells are dead and contain large quantities of collagen.|
Like all outer epithelial cells, the cells of a psoriasis blemish are dead and highly keratinized, which is what gives them the scaly appearance. All of the other choices do not make sense, and are not supported by the passage.