Module 4: Integument and Somatosensation
Learning Objectives:
By the end of this module, students will be able to:
- List the functions of the integument.
- Identify the two primary layers of the skin.
- Differentiate the sub-layers of the epidermis.
- Differentiate the sub-layers of the dermis.
- Contrast thin skin and thick skin.
- Summarize the cells of the epidermis.
- List the function of the cells.
- Identify the structures derived from the epidermis.
- Describe the characteristics and function of the structures derived from the epidermis.
- List the sensory receptors of the skin.
- Subdivide the unencapsulated and encapsulated receptors.
- Differentiate the location and primary function of the sensory receptors of the skin.
- Categorize the receptors into the pathways the signals would travel through the spinal cord.
Terms to Know
|
Integument
|
Somatosensation
|
The skin and accessory structures perform a variety of essential functions, such as protecting the body from invasion by microorganisms, chemicals, and other environmental factors; preventing dehydration; acting as a sensory organ; modulating body temperature and electrolyte balance; and synthesizing vitamin D. The underlying hypodermis has important roles in storing fats, forming a “cushion” over underlying structures, and providing insulation from cold temperatures.
Integument Functions
- Protection
- Water regulation
- Temperature regulation
- Vitamin D synthesis
- Sensory perception
- Excretion by secretion (discussed in lecture)
- Storage (discussed in lecture)
- Non-verbal communication (discussed in lecture)
Protection and Water Regulation
The skin protects the rest of the body from basic elements such as wind, water, and UV sunlight. It acts as a protective barrier against water loss due to layers of keratin and glycolipids in the stratum corneum. It also is the first line of defense against abrasive activity due to contact with grit, microbes, or harmful chemicals. Sweat excreted from sweat glands has antibiotic properties and deters microbes from over-colonizing the skin surface.
Temperature Regulation (Thermoregulation)
The integumentary system helps regulate body temperature through its tight association with the sympathetic nervous system. The sympathetic nervous system is continuously monitoring body temperature and initiating appropriate motor responses. Sweat glands secrete water, salt, and other substances to cool the body when it becomes warm. If the body becomes excessively warm due to high temperatures, vigorous activity, or a combination of the two, sweat glands will be stimulated by the sympathetic nervous system. When the sweat evaporates from the skin surface, the body is cooled as body heat is dissipated. In addition to sweating, arterioles in the dermis dilate so that excess heat carried by the blood can dissipate through the skin and into the surrounding environment.
Fun Fact – Sweat (-> you will not be assessed on this content)
The sympathetic nervous s