Nursing Preparation Study Guide

Nursing Preparation Study Guide The skin acts as a receptor for: • Touch • Pressure • Pain • Heat • Cold These receptors are also parts of the somatosensory system. Because the skin receives a plethora of stimuli, it plays a major role in an individual’s adaptation to their environment. The skin also acts as an early warning system for unhealthy conditions. 6.3.2 Components Our skin consists of two main layers, the epidermis and the dermis, which contain several other components: Epidermis: Stratified, squamous epithelium makes up the epidermis. This layer is avascular, meaning it does not have any blood vessels. Without local blood vessels, epidermal cells receive nutrients and oxygen by diffusion from capillaries located in the dermis. The basal layer is mitotic and new cells are pushed up superficially over time. • The cells found in the epidermis are: keratinocytes , which produce the fibrous protein keratin, and melanocytes , which produce the brown pigment melanin. Langerhans’ cells , are epidermal macrophages that help activate the immune system, while Merkel cells function as touch receptors in sensory nerve endings. • The word stratum means “layer”. The strata of the epidermis are the stratum germinativum, the stratum spinosum, the stratum granulosum, the stratum lucidum, and the stratum corneum. • Renewal of the epidermis, also known as the process of maturation and desquamation, takes around 21 days. Nails develop in the epidermis and extend down into the dermis. Dermis: The dermis lies between the epidermis and the subcutaneous layer, and is called the “true skin” because it contains blood vessels and nerves that support these layers . The dermis has two major components: a superficial papillary layer and a deeper reticular layer. These layers contain a variety of connective tissues, such as collagen and elastin, which allow skin to stretch and flex. Additionally, the dermis helps cushion the body from stresses. The base of sweat glands and sebaceous glands are also located in the dermis. Hair follicles may extend downward into the underlying connective tissue. • Sweat glands: Sweat glands are small, tubular structures of the skin that produce sweat. Eccrine sweat glands are located throughout the body. These play a key role in perspiring and cooling the skin. Apocrine sweat glands are larger and limited to the armpits and pubic areas; these become active during puberty and secrete odorous sweat.

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