-
What
are the major functions of the integumentary system?
Protection
-
What
are the major functions of the integumentary system?
Body temperature regulation
-
What
are the major functions of the integumentary system?
Sensory Perceptions
-
What
are the major functions of the integumentary system?
Synthesis of vitamin D
-
What
are the major functions of the integumentary system?
Emotional expression
-
What
are the major functions of the integumentary system?
Reservoir of blood
-
What is keratinization?
process of replacing viable cells in the stratum basale with more and more of the waxy keratin protein as cells move from the deepest layer to the surface layer
-
Epidermis Cells
Keratinocytes: makes up 90% of the cells. produce keratin (a tough fibrous protein that provides protection)
-
Epidermis Cells
Melanocytes: produce the pigment melanin that protects against damage by UV radiation
-
Epidermis Cells
Langerhans cells: macrophages that originated in the red bone marrow. They are involved in the immune responses
-
Epidermis Cells
Merkel cells: function in the sensations of touch alone with the other adjacent tactile discs (receptors)
-
Layers of Epidermis
- stratum basale: bottom
- (deepest) layer. Continuous cell division occurs here and produces all the
- other layers.
-
Layers of Epidermis
- stratum spinosum:8–10
- keratinocytes
-
Layers of Epidermis
- The
- non-dividing cells of the 3rd
- layer (stratum granulosum) are
- filled with granules of keratin.
-
Layers of Epidermis
- stratum lucidum:4th
- layer but is only present in thick skin (the skin of the fingertips, palms, and
- soles).
-
Layers of Epidermis
- stratum corneum: always
- outermost, composed of approximately 20 layers of flat cell-remnants that are
- like “bags of turtle wax” (dead keratinocytes with no cellular organelles
- filled with only keratin protein.)
-
DERMIS
is composed of connective tissue containing collagen and elastic fibers.
-
TWO REGIONS OF DERMIS
- papillary region: lies
- just below the epidermis and consists of areolar connective tissue containing
- thin collagen and elastic fibers, dermal papillae (including capillary loops),
- corpuscles of touch and free nerve endings.
-
TWO REGIONS OF DERMIS
- reticular region: consists
- of dense
- irregular connective tissue containing collagen and elastic fibers,
- adipose cells, hair follicles, nerves, sebaceous (oil) glands, and sudoriferous
- (sweat) glands
-
Lines of cleavage
- are “tension lines” in the
- skin that indicate the predominant direction of underlying collagen fibers.
-
epidermis
- resists
- damage and offers protection to underlying tissues.
-
dermis
- provides
- temperature stability and prevents dehydration, and yet is capable of limited healing.
-
These sensory receptors are found in different layers
Superficially
- •Merkel
- discs, free nerve endings (detect many stimuli), Meissner
- corpuscles, and hair root plexuses
-
-
What are the major parts of the hair?
The shaft (above the skin surface)
The follicle (below the level of the skin)
A root that penetrates into
the dermis includes:
•An epithelial root sheath
•A dermal root sheath
-
What is the function of hair?
- Hair helps with touch sensations and protects the body against the harmful effects
- of the sun and against heat loss.
-
What are the major skin glands
Sebaceous (oil) glands are connected to hair follicles.
They secrete an oily substance called sebum which does 2 important things:
•Prevents dehydration of hair and skin
•Inhibits growth of certain bacteria
-
What are the major skin glands
- Eccrine sweat glands are the most numerous. They secrete a watery solution (600 ml per day) that helps
- to cool the body and eliminates small amounts of waste.
-
What are the major skin glands
- Apocrine sweat glands are
- located mainly in the skin of the axilla, groin, areolae, and bearded facial
- regions of adult males. They secrete a slightly viscous sweat (Where body odor comes from)
-
What are the major skin glands
Ceruminous glands are modified sweat glands located in the ear canal.
-
wound healing
Epidermal wound healing occurs following superficial wounds that affect only the epidermis.
Return to normal function is the rule
-
Wound healing
Deep wound healing occurs when an injury extends to the dermis and subcutaneous layer.
Loss of some function and development of scar tissue is the rule.
-
-
|
|