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Structure and Function of The Skin

»	Name the three layers of the skin. What composes them?
»	How many layers are there in the epidermis? How are they organized?
»	Do other types of cells normally occur in the epidermis?
»	What is apocopation?
»	Describe the structure of the basement membrane zone (BMZ).
»	How is the structure of the epidermis related to its functions?
»	What structural components of the epidermis are involved in blistering diseases?
»	Are there hereditary diseases of the BMZ and dermis that cause blistering and damage to the skin?
»	Are there acquired blistering diseases of the BMZ and dermis?
»	What abnormalities in structural components of the basement membrane are involved in bullous skin diseases?
»	What is the function of the sebaceous gland?
»	How do the eccrine sweat glands and apocrine sweat glands differ?
»	How is the dermis organized?
»	What are the components of the dermis?
»	What are the functions of the dermis?
»	Which structural component of the dermis is involved in congenital and autoimmune skin diseases?
»	How does the vasculature of the dermis function in temperature control?
»	How is the skin innervated?
»	Name the two main corpuscular (encapsulated) nerve receptors found in the skin.
»	Is loss of cutaneous sensation very serious?
»	How is the subcutis organized?

Name the three layers of the skin. What composes them?

Fig. 1.1 Structure of the skin.

The epidermis, dermis, and subcutis (subcutaneous fat). The epidermis is the outermost layer and is composed primarily of keratinocytes, or epidermal cells. Beneath the epidermis lies the dermis, which is composed primarily of collagen but also contains adnexal structures, including the hair follicles, sebaceous glands, apocrine glands, and eccrine glands. Numerous blood vessels, lymphatics, and nerves also traverse the dermis. Below the dermis lies the subcutis, or subcutaneous layer, which consists of adipose tissue, larger blood vessels, and nerves. The subcutis may also contain the base of hair follicles and sweat glands (Fig. 1-1).