| Integument System Overview | The Epidermis | The Dermis | Glands | Hair | Nails |
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Integumentary System Overview

Objectives:
  1. Identify the functions of the integument.
  2. Identify the gross and microscopic anatomy of the skin including the epidermis and dermis.
  3. Understand the structure and function of the skin layers.
  4. Identify the structure and function of integument accessory structures: glands, hair, and nails.

Skin - Click on each label to view definition
Overview Skin Epidermal ridge - Ridge located in the epidermis formed by the underlying dermal papilla. Sweat pore - Opening on the epidermis for a sweat gland. Hair shaft - Portion of the hair that projects from the epidermis. Epidermis - The superficial layer and is composed of epithelial tissue. Capillary loop - Small blood vessels (capillaries) located in the papillary region of the dermis. Sebaceous (oil) gland - Gland producing lipid-rich product that moistens the hair and skin. Dermis - The layer of the skin just deep to the epidermis composed of connective tissue, blood vessels, nerves, nerve receptors, and muscle tissue. Subcutaneous layer - Connective tissue layer located deep to the skin also known as the hypodermis. It contains adipose tissue, blood vessels and receptors for pressure. It is not considered to be part of the integument. Reticular region - The deepest portion of the dermis containing the majority of the structures seen in the dermis. Hair follicle - Hair containing extension of the epidermis located in the dermis. Hair root - Portion of the hair located in the hair follicle. Vein - Blood vessel carrying blood away from integument. Artery - Blood vessel carrying blood towards integument. Eccrine sweat gland - Sweat gland that produces a watery sweat and empties onto the surface of the skin via a pore. These glands are located primarily at the palms of the hands, soles of the feet and forehead and are involved in thermoregulation. Adipose tissue - Composed of adipocytes (fat cells). Apocrine sweat gland - Sweat gland producing perspiration rich in lipid and protein components. Located at the axillary and public region and the areola of each nipple. Sensory nerve - Nerve that replays information concerning external stimuli towards the central nervous system. Lamellated (pacinian) corpuscle - Specialized deep pressure and vibration receptors located deep in the dermis or hypodermis. Corpuscle of touch (meissner corpuscle) - Touch receptors located at the dermis. Dermal papilla - Finger-like projections of the dermis located at the papillary region. Arrector pili muscle - Smooth muscles connected to hair follicles; their contraction causes the hair to become erect; seen with excitement, fear and cold. Free nerve ending - Nerve receptors located in the deeper portions of the epidermis. They are unencapsulated and can detect pain, touch or itch stimuli.

Introduction:
The integument is composed of the skin and associated structures including hair, nails, sensory receptors and glands.  It forms a physical barrier between the external environment and the body.  This barrier prevents blood and fluid loss and provides protection against physical trauma, bacteria, viruses, parasites, chemicals, and ultraviolet radiation. 

Structure:
The skin is composed of two layers: the epidermis and dermis.

Function:

  1. Protection.
  2. initial steps of vitamin D formation.
  3. location for various sensory receptors for touch, pressure, vibration, hot, cold, and pain.
  4. excretion of water, metabolic wastes and electrolytes in perspiration.
  5. Body temperature regulation (Thermoregulation) via evaporation of perspiration on the skin surface and the movement of blood within the deep layer of the skin.
Bluedoor Publishing 2011