Unit 3 - Integumentary System Flashcards
Define the integumentary system
Complex set of organs that includes skin and its derivatives
What does the integumentary system include?
Sweat and oil glands, hairs, and nails
Nerves, blood vessels, muscles, sensory elements
List the 6 functions of skin
Protection Thermoregulation Cutaneous sensation Metabolic functions Blood reservoir Excretion
Explain the difference between the epidermis and the dermis
Epidermis is made of stratified squamous epithelium
Dermis includes papillary and reticular layers
Describe the structure of the subcutaneous layer.
The hypodermis is the subcutaneous layer lying below the dermis; it consists largely of fat. It provides the main structural support for the skin, as well as insulating the body from cold and aiding shock absorption. It is interlaced with blood vessels and nerves
Explain what happens to epidermal cells as they undergo keratinization.
Keratinocytes arise from the deepest layer of the epidermis produced by stem cells in the stratum basale. They undergo continuous mitosis, those cell push up by the production of new cells beneath them. By the time they reach the new skin surface, they die and create a scale-like structure with more than a keratin-filled plasma membrane. Millions of these dead cells rub off daily and humans replace their skin completely ever 25-45 days.
List the 5 layers of the epidermis
Stratum corneum Stratum lucidum Stratum granulosum Stratum spinosum Stratum basale
The outermost layer of the epidermis and marks the final stage of keratinocyte maturation and development
Stratum corneum
A thin somewhat translucent layer of cells lying superficial to the stratum granulosum and under the stratum corneum especially in thickened parts of the epidermis
Stratum lucidum
A layer of granular nondividing cells above the stratum spinosum
Stratum granulosum
The layers of prickle cells over the layer of the stratum basale capable of undergoing mitosis.
Stratum spinosum
The deepest layer, separated from the dermis by the basement membrane and attached to the basement membrane by hemidesmosomes.
Stratum basale
Describe the location, structure, and function of melanocytes.
Found in deepest layer of epidermis
Synthesizes melanin
Accumulated in melanosomes
Moved along actin filaments to melanocyte’s processes
Describe the structure of the dermis
Strong flexible connective tissue layer beneath epidermis which consists of two layers (papillary, reticular)
What makes up the dermis?
The dermis contains nerve endings, sweat glands and oil glands (sebaceous glands), hair follicles, and blood vessels.
Explain the functions of the subcutaneous layer.
Binds skin to underlying tissues
Subcutaneous fat which acts as an energy reservoir and thermal insulation
Explain the structure and function of sebaceous glands.
Sebaceous glands secrete sebum which coats and protects the hair shaft
Explain the importance of body temperature regulation.
Body temperature must be controlled within a very narrow range so that the body can function properly. In particular, enzymes in a body’s cells must have the correct temperature to be able to catalyze chemical reactions. High temperatures can cause dehydration, heat stroke and death if untreated.
Explain the role of the skin in promoting the loss of excess body heat.
In intense heat, the nerve impulses stimulate the skin and other organs to release heat. The muscles, when active, release heat. As excessive body heat is lost, the brain triggers responses in skin structure.
Explain the body’s response to decreasing body temperature.
The body decreases blood flow to conserve body heat
Explain how environmental factors affect skin color.
- Populations native to tropics and their descendants tend to have well-melanized skin to screen out excessive UVR
- Populations native to far northern or southern latitudes have light skin to allow for adequate UVR penetration
- Ancestral skin color is a compromise between vitamin D and folic acid requirements
Describe three physiological factors that affect skin color.
Melanin
Hemoglobin
Carotene
Distinguish between the healing of shallow and deeper breaks in the skin.
- Shallow - Epithelial cells along the margin divide more than usual, new cells fill the gap.
- Deep - Cut into dermis or subcutaneous. Blood vessels break, escaping blood forms a clot, mostly fibrous protein (fibrin), blood cells, and platelets trapped fibers. Tissues fluids seep into the area and dry. Clot and dry fluids create a scab that covers and protects the healing tissue. Fibroblasts begin forming new collagenous fibers tag bind edges of wound together.
Describe the characteristics of a first-degree burn
Marked by redness, slight edema, and pain
Describe the characteristics of a second-degree burn
Blisters; skin regeneration occurs with little or no scarring
Describe the characteristics of a third-degree burn
Burned area appears gray-white, cherry red, or blackened; excessive scar tissue forms
What percentage of the body burned is considered a threatening 2nd degree burn?
Over 25%
What percentage of the body burned is considered a threatening 3rd degree burn?
Over 10%
Explain what types of burns pose a threat to life and describe the most significant threats major burns pose.
- 3rd degree burns of face, hands, or feet
- Burns at joints can cause scar tissue formation which may severely limit joint mobility
- Deaths result primarily from fluid loss, infection, and toxic effects of eschar
What is a possible treatment for 3rd degree burns?
Skin grafts
What are the 3 effects of aging on the skin?
Appearance
Temperature regulation
Vitamin D activation
What is the appearance effect of aging on the skin?
Epidermis thins with age. Skin may appear scaly. Patches of pigment called age spots. Shrinking dermis and loss of some fat from subcutaneous layer results in wrinkling and sagging. Decrease in oil from subcutaneous glands dries the skin. Pale complexion from fewer blood vessels
What is the temperature regulation effect of aging on the skin?
Less able to tolerate the cold and cannot regulate heat.
What is the vitamin D activation effect of aging on the skin?
Less exposure to sun and skin needs it to produce Vitamin D.
