Ch.5 Flashcards
What does integumentary system consist of?
Integument and it’s accessory organs
The Integument is the….
Skin
The Integuments accessory organs include:
Nail
Hair
Sweat glands
Subcuous(oil)glands
The integument consist of?
Superficial epidermis and the deeper dermis
Where does subcutaneous layer(hypodermis) is located?
Deep to the dermis
Not part of Integument
Where does Integument accessory are formed and reside?
Formed from epidermis
Reside in dermis
Integumentary system functions
Protection Temperature regulation Vitamin D synthesis Sensory reception Excretion Blood reservoir
Stratum basale
Deepest epidermal layer (in contract with basement membrane below)
A single layer of cells but 3 types(keratinocytes,melanocytes,tactile cells)
Keratinocytes
- Cells that will ultimately produce Keratin
- They actively divide(mitosis) to push new keratinocytes up to the more superficial layers
Melanocytes
Produce the pigment melanin
Tactile cells
Sensory receptor
Stratum spinosum
- several cell layers
- keratinocytes begin to produce keratin
- immune cells(epidermal dendritic cells) are also present
Keratin
Durable protein that makes the epidermis tough and waterproof
Stratum granulosum
- Three to five layers of keratinocytes undergoing ‘keratinization’ which includes loss of organelle and nucleus
- keratin is fully formed and cell is dead
Stratum lucidum
- a few layers of dead keratinocytes
- found only in thick skin
- provides extra protection in thick skin
Where do you find thick skin?
Palms of the hands
Soles of the feet
Finger tips, and toe tips
Stratum corneum
-Most superficial epidermal layer(in contract with the external environment)
-largest stratum with ~30 layers(many more in thick skin)of dead keratinocytes
Keratinocytes sloughed off by abrasion, replaced by keratinocytes pushed up from the deeper epidermal layers
Dermis
- The deeper, thicker layer of integument
- very vascular(blood reservoir)
- 2 regions (papillary layer, reticular layer)
Papillary layer
- the superficial, thinner layer of the dermis(in contract with the basement membrane of the epidermis above)
- dermal papillae and epidermal ridges interlock to increase the surface area of contact between the dermis and epidermis
Dermal papillae function
- Contain capillaries, providing nutrients to and receiving wastes from the epidermis
- the papillae also contain sensory receptors
Reticular layer
- The deeper, thicker layer of the dermis
- compromise the majority of the integument
- contain dermal blood vessels, sensory receptors, and the integuments accessory organs(gland and hair follicles)
Subcutaneous layer(hypodermis)
- also known as superficial fascia
- deep to the dermis
- thickness varies with location in the body
- consist of adipose connective tissue(plus some areolar connective tissue)
- binds the integument to the underlying muscle and other organs
- cushioning,insulation,and energy reserve
Nails
- Nails,hair,sweat and sebaceous glands are derived from epidermis and develop as invaginations of the epidermis into the dermis
- derived from the same type of cells as the stratum corneum of the epidermis
- contain hard keratin(prevents individual cells from sloughing off)
Nails consist of what?
A free edge(extending off of the finger or toe)
A nail body(the visible attached portion)
A nail root(the proximal portion embedded in the integument)
Lanula(whitish semilunar area at the proximal end)
Hair
- found everywhere on the body except for the palms of the hands, the soles of the feet, the lips, and the nipples
- made of hard keratin
- 3 types of hair: lanugo, vellus, terminal
Lanugo
Very fine, unpigmented hair of a fetus. Mostly replaced by birth
Vellus
Hair on most of the body
Terminal hair
Found on scalp, eyebrow, eyelashes, beard, and in the axillary and pubic regions following puberty.
Hair structure
- The shaft is the part that extends beyond the skin surface
- the root is the part within the follicle internal to the skin surface
- the bulb
Hair-bulb
- Expanded base of the root
- consist of living epithelial cells even though it is located deeply within the dermis-it is swollen part of the base
- surrounds the hair papilla which contains tiny blood vessels and nerves.
- within the bulb is the hair matrix where the hair is actually produced
- malanocytes are located here
Hair follicle
- Surrounds the hair root and hair bulb( at the base of the follicle is an in folding of the dermis into the hair bulb, called the hair papilla, which contains the capillaries that provide nutrients to the developing hair
- arrector pilli muscle is attached to each hair follicle(stimulated by emotion or exposure to cold-when the muscles contract the hair is elevated producing what is commonly called “goose bumps”
Integumentary system glands
Sweat(sudoriferous)glands
-merocrine sweat glands
-apocrine sweat glands
Sebaceous(oil) glands
Merocrine sweat glands
-very numerous and widely distributed
Almost everywhere
Particularly abundant on palms, soles and forehead
-sweat(merocrine) is secreted directly onto the integument surface by way of a pore
-99% water
1% salts, antibodies, and waste products
Functions in temperature regulation,immunity, and excretion
Apocrine sweat glands
-less numerous, with a limited distribution
Axillary and pubic regions
-sweats(apocrine) is released into a hair follicle(the secretion is more viscous, containing lipid and proteins)
-is not involved with temperature regulation
Apocrine sweat glands become functional during puberty
Are involved with chemical signaling
Sebaceous glands
-Located everywhere in the body except the palms and soles
Particularly abundant on the face,neck, and upper chest and back
-produce sebum, an oily secretion
Sebum is released into a hair follicle
Sebum functions in lubrication of the hair and integument
