SAS 3 Flashcards
(45 cards)
the skin, or _______ is considered an organ because it…
consists of all four tissue types
consists of accessory organs, such as glands, hair, and nails, thus making up the integumentary system.
skin
two primary layers of skin
epidermis and the underlying dermis
although technically not part of the skin, the _______ (subcutaneous layer, or superficial fascia) lies beneath the dermis
hypodermis
the skin performs a variety of functions:
Protection - provided against infection by microbes, physical damage, harmful chemicals and ultraviolet radiation
Sensation - provided by nerve endings for touch, pain, and heat keeping the body informed of changes in its environment
Thermoregulation - supported through the sweating and regulation of blood flow through the skin
Synthesis of vitamin D - occurs in the skin
Excretion - of salts and small amounts of wastes (ammonia and urea) occurs with the production of sweat
LAYERS OF THE SKIN
- Epidermis
- Dermis
- Hypodermis
consists of keratinized stratified squamous epithelium
Epidermis
produce keratin, a protein that hardens and waterproofs the skin; mature keratinocytes at the skin surface are dead and filled almost entirely with keratin
Keratinocytes
produce melanin, a pigment that protects cells from ultraviolet radiation; melanin from the melanocytes is transferred to the keratinocytes
Melanocytes
phagocytic macrophages that interact with white blood cells during an immune response
Langerhans cells
occur deep in the epidermis at the epidermal dermal boundary; they form Merkel discs, which, in association with nerve endings, serve a sensory function
Merkel cells
Thick skin, thin skin
five, four layers
5 layers making up the epidermis
- Stratum corneum
- Stratum lucidum
- Stratum granulosum
- Stratum spinosum
- Stratum basale / germinativum
contains many layers of dead, anucleate keratinocytes completely filled with keratin
Stratum corneum
contains two to three layers of anucleate cells
Stratum lucidum
contains two to four layers of cells held together by desmosomes; these cells contain keratohyalin granules, which contribute to the formation of keratin in the upper layers of the epidermis
Stratum granulosum
contains eight to ten layers of cells connected by desmosomes
Stratum spinosum
contains a single layer of columnar cells actively dividing by mitosis to produce cells that migrate into the upper epidermal layers and ultimately to the surface of the skin
Stratum basale / germinativum
second layer of the skin
consists of various connective tissues
Dermis
contains fibroblasts and macrophages within a gelatinous matrix containing collagen, elastic and reticular fibers
provides strength, extensibility (the ability to be stretched), and elasticity (the ability to return to its original
Dermis
where we find capillaries and many nerve endings
major blood vessels are found in the hypodermis
Dermis
two layers of dermis
- Papillary layer
- Reticular layer
thin outer layer of areolar connective tissue with fingerlike projections called dermal papillae that protrude into the epidermis
Papillary layer
thick layer of dense irregular connective tissue
Reticular layer
