Unit 1.3 Flashcards
Components of the integumentary system
Skin (cutaneous membrane)
Accessory structures
Skin (cutaneous membrane)
Composed of squamous cells also known as keratinocytes
Epidermis, dermis, hypodermis (not truly part of the skin but studied for convenience)
Accessory structures
Hair, nails, associated glands
Functions of the skin
Protection- barrier to the outside world and inhibits dehydration
Excretion- sweat release ions (electrolytes) and water
Thermal regulation- sweat cooled the body, hair traps air and warms the body
Synthesis of vitamin d- necessary for Ca++ absorption and proper function of most cells
Perception of the environment- sensory nerve ending and special tactile cells (Merkle) in skin transmit information to the CNS
Epidermis
Contains
Desquamification of keratincytes
Germinal basement membrane at epidermal-dermal papilla
Is avascular but does not have nerves- blood is receives at the germinal membrane but no further
Dermis
Contains
Papillary layer is areolar connective tissue
Reticular layer is dense irregular connective tissue and contains blood vessels, nerves, hair follicles, sweat and sabecceous glands
Hypodermis
contains
Adipose connective tissue
Areolar connective tissue
Contains vessels, nerves, lymphatics
The epidermis is _ the dermis
Above
The epidermis is approximately _ of the total volume of the skin
20%
(Epidermis) Germinal cells (undergo mitosis) are at the _ ;
Basement membrane (papillary region)
They mature as they move toward the periphery and eventually die
(Epidermis) the superficial most layer of _ undergo a process called
Time
Squamous cells
Desquamation (shedding of skin)
Entire process takes 4 weeks
Micro anatomy of the epidermis
Stratum basale
Stratum spinosum
Stratum granulosum
Stratum lucidum
Stratum corneum
Stratum basale
Contains melanocyte (pigment producing cell) and cells that transmit sensory (tactile) information; merkle cells
Stratum spinosum
Contains langerhan cells (phagocytic immune cell)
Stratum granulosum
Contains granule active in keratinization
Stratum lucidum
Is only found in thick skin (palms of hands and soles of feet)
Stratum corneum
Contains cells that are cleated and keratinized
Layers of the dermis
Papillary layer
Reticular layer
Dermis is approximately _ of skin volume
80%
Papillary layer
Composed of areolar connective tissue
Papilla (nipple$ project into epidermis forming fridges
Contains blood vessels and nerves
Reticular layer
Dense irregular connective tissue
Bundles of collagen and elastin fibers
Types of glands (accessory structures) of the skin
Sebaceous (oil) glands
Merocrine (sweat) glands
Apocrine (sweat) glands
Sebaceous glands
Secretes sebum into hair follicle
Sebaceous follicle excretes debris onto the surface of the skin- protects the body from dehydration and provides a measure of insulation
Merocrine glands
Secretes water and electrolytes that provide the body with thermal regulation
The most abundant of glands and most widely distributed
Apocrine sweat glands
Secrete a sticky cloud and odorous secretion
Found at the armpits, nipples, and groin
Is the hypodermis part of the cutaneous membrane?
No- subcutaneous tissue
Hypodermis
Loose areolar and adipose connective tissue
Contains large arteries and veins and nerves
Hair
Composed of dead keratinocytes
Germinal cells are in the hair bulb lining the papilla
Affect or pulling muscle contracts to raise hair and trap air
Sebaceous glands are sebum (oil) producing glands; sebum lubricates the hair and skin
Color of hair is dependent upon genetics/ composition of pigments
Nails
Dead keratinocytes that are cornified- hardened waxy cells
Similarly between hair and nails
Similar to hair but instead of having a hair bulb and papilla there is a germinal plate and nail bed
Similar to skin in that cells are stratified squamous (keratin producing) nails can split longitudinally or in layers
