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59 Cards in this Set

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The organ that includes the cutaneous membrane and skin appendages (hair, nails, sweat glands, sebaceous glands, etc..)
the integument
The largest organ system of the body
the integumentary system
Skin is a cutaneous membrane consisting of 2 parts: the _______ and ________.
epidermis
dermis
Describe the epidermis.
keratinized stratified squamous epithelium
Describe the dermis.
2 layers
the papillary layer - areolar connective tissue proper
the reticular layer - dense irregular connective tissue proper
Where is the dermis?
just deep to the epidermis
List the protective functions of skin.
1. protects the underlying tissue against mechanical stress and abrasion
2. protects against fluid loss and dessication of the underlying tissue
3. protects against micro-organisms invading the body
4. protects the underlying tissue against UV-damage by the sun
How does the integument protect against micro-organisms?
1. tight junctions keep micro-organisms out
2. the acid mantle (low pH of skin secretions) slows the growth of micro-organisms on the skin
3. skin secretions have bactericidal components
4. the skin contains cells of the immune system
Term describing the regulation of body temperature
thermoregulation
How is the integument involved in thermoregulation?
1. sweat gland secretions
2. dilation or constriction of dermal blood vessels
When the body is overheated, dermal blood vessels will __________.
Explain.
dilate
This brings more blood to the body's surface where extra heat can radiate out of the body.
When the body is too cold, dermal blood vessels will __________.
Explain.
constrict
This conserves heat in the body by bringing less blood to the body's surface where body heat could radiate away.
How is the integument involved in Ca²⁺ homeostasis?
Vitamin D3 (a precursor of the active form of vitamin D) is created by the action of UV light in dermal blood vessels.
The active form of vitamin D.
calcitrol
Why is calcitrol important for Ca²⁺ homeostasis?
Calcitrol helps maintain Ca²⁺ homeostasis by enhancing the absorption of Ca²⁺ from the gastrointestinal tract.
Cells that produce the pigment melanin.
melanocytes
Phagocytic antigen-presenting cells found in the epidermis.
Langerhans' cells
Cells in the epidermis that function as touch receptors in association with sensory nerve endings.
Merkel cells
Merkel cell + nerve ending = ?
Merkel disc (or tactile disc)
Epithelial cells, specialized for the cutaneous membrane, that produce large amounts of the fibrous protein keratin.
keratinocytes
The epithelium of the integument
the epidermis
The connective tissue supporting the epithelium of the integument
the dermis
The epithelial cells of the epidermis have extra-strong intermediate filaments, called tonofilaments. Tonofilaments are made from the protein _________.
keratin
List the 5 layers of the epidermis of thick skin in order from the basal layer to the apical surface.
stratum basale
stratum spinosum
stratum granulosum
stratum lucidum
stratum corneum
Which layer of the epidermis...?

Kerotinocytes undergo constant cell division.
stratum basale
Alternative name for the stratum basale...

Explain.
stratum germinativum
Cell division in the stratum basale produces the cells of the more superficial strata.
The skin pigment that strongly absorbs UV light.
melanin
Which layer of the epidermis...?

The keratinocytes continue to produce keratin, which they assemble into thick bundles called tonofilaments.
stratum spinosum
Which layer of the epidermis...?

Cells are flattened due to dehydration.
Programmed cell death begins.
stratum granulosum
Which layer of the epidermis...?

Cells contain dark-staining granules...
stratum granulosum
What is apoptosis?
programmed-cell death

an orderly series of steps by which cells commit suicide
Which layer of the epidermis...?

The "clear layer" visible only in thick skin...
stratum lucidum
Which layer of the epidermis...?

The cells in this layer are dead, flat, dehydrated membranous sacs filled with keratin.
accounts for three quarters of the epidermal thickness
stratum corneum
The more superficial layer of the dermis.
the papillary layer
The deeper layer of the dermis...
the reticular layer
What type of tissue is the papillary layer of the dermis?
areolar connective tissue proper
What type of tissue is the reticular layer of the dermis?
dense irregular connective tissue proper
Dermal papillae are most prominent in _______________.
thick skin
Which layer accounts for approximately 80% of the thickness of the skin?
the reticular layer of the dermis
In the reticular layer of the dermis, ______________ are oriented to follow lines of tension in the skin.
collagen fibers
Subcutaneous layer deep to the skin composed of fat cells and areolar connective tissue proper...
the hypodermis
The tough connective tissue wrapping skeletal muscles...
fascia
sweat glands
sudoriferous glands
oil glands
sebaceous glands
List the different skin appendages.
sweat glands
oil glands
hair follicles and hair
nails
The secretion produced by sebaceous glands...
sebum
What does sebum do for the skin?
Sebum softens and lubricates skin and hair and is bactericidal.
Sebaceous glands mode of secretion...
holocrine
Sudoriferous glands that produce sensible perspiration...
merocrine (eccrine) sweat glands
Visible sweat is referred to as ______________.

Explain why?
sensible perspiration

Sensible perspiration represents water loss for a reason - to cool the body as it evaporates.
Physiologists refer to sweating as _________.
diaphoresis
Merocrine sweat glands are particularly abundant on the...
palms of hands, soles of feet, and forehead
Sudoriferous glands that produce odorless secretion that takes on a musky odor after decomposition by bacteria.
apocrine sweat glands
Which regions of the body are densely populated by apocrine sweat glands?
the axillae, genital region, areolae, and bearded regions of face
Modified apocrine sweat glands in external ear canal that secrete ear wax...
ceruminous glands
The physiological term for ear wax.
cerumen
Where on the body is thick skin found?
the palms, palmar surface of the digits, and soles of the feet
Which stratum of the epidermis is apparent only in thick skin?
the stratum lucidum
__________ - skin devoid of hair
glabrous skin