Ch 5: Skin
The _________________ is the largest system of the body
-Sixteen
percent of body weight
Integument
The integument is made up of two parts ________________ and ___________________.
Cutaneous membrane (skin)
Accessory structures
_________________ originate in the dermis and extend through the epidermis to skin surface. Includes Hair, Nails, and Multicellular exocrine glands
Accessory Structures
Functions of ___________ are Protection of underlying tissues and organs; Excretion of salts, water, and organic wastes (glands); Maintenance of body temperature (insulation and evaporation); Production of melanin
Skin
Functions of _________:
Production of keratin
Synthesis of
vitamin D3
Storage of lipids
Detection of touch, pressure,
pain, and temperature
Skin
_______________________ has sensory receptors that detect touch, pressure, pain, vibration, and temperature. Blood vessels assist in thermoregulation.
Reticular Layer
The ________________ is avascular stratified squamous epithelium. Nutrients and oxygen diffuse from capillaries in the dermis
Epidermis
__________________ Contain large amounts of keratin and
Are the
most abundant cells in the epidermis
Keratinocytes
_________________ is keratinocytes produce keratohyalin and keratin; Keratin fibers develop as cells become thinner and flatter; Gradually the plasma membranes thicken, the organelles disintegrate, and the cells die
Stratum granulosum
Stratum Basale is attached to basement membrane by _______________________.
hemidesmosomes
Stratum Basale forms epidermal ridges which are the basis of _______________.
fingerprints
______________ are tiny mounds that increase the area of basement membrane and strengthen attachment between epidermis and dermis
Dermal papillae
Stratum Basale has many basal cells, or ___________________.
germinative cells
Specialized Cells of Stratum Basale are ______________ and _________________.
merkel cells and melanocytes
_____________ found in hairless skin and responds to touch (trigger nervous system)
Merkel cells
____________________ contain the pigment melanin and are scattered throughout stratum basale
Melanocytes
_________________ — the “spiny layer” produced by division of stratum
basale; Eight to ten layers of keratinocytes bound by desmosomes;
Cells shrink until cytoskeletons stick out (spiny)
Continue to
divide, increasing thickness of epithelium
Contain dendritic
(Langerhans) cells, active in immune response
Stratum Spinosum
___________________ is the “grainy layer” that stops dividing, starts producing: Keratin and Keratohyalin
Stratum Granulosum
______________ is a tough, fibrous protein that makes up hair and nails
Keratin
______________ are dense granules that Cross-link keratin fibers
Keratohyalin
Cells of ______________________ produce protein fibers, dehydrate and die, create tightly interlocked layer of keratin surrounded by keratohyalin
Stratum Granulosum
_________________ is the “clear layer” and found only in thick skin. It covers the stratum granulosum
Stratum Lucidum
_______________ is the “horn layer” that is exposed surface of skin; 15 to 30 layers of keratinized cells; Water resistant; Shed and replaced every two weeks
Stratum Corneum
_________________ is the formation of a layer of dead, protective cells filled with keratin; Occurs on all exposed skin surfaces except eyes. Skin life cycle: It takes 7 to 10 days for a cell to move from stratum basale to stratum corneum
Keratinization
__________________ interstitial fluid lost by evaporation through the stratum corneum
Insensible perspiration
______________ results from immersion in hypertonic solution (e.g., seawater [osmosis])
Dehydration
______________ results from immersion in hypotonic solution (e.g., freshwater [osmosis]) Causes swelling of epithelial cells, evident on the palms and soles
Hydration
Skin Color Is Influenced by Two Pigments: ____________ and ______________ and Blood circulation (red blood cells)
Carotene and Melanin
_______________ is orange-yellow pigment that is found in orange vegetables and accumulates in epidermal cells and fatty tissues of the dermis. It can be converted to vitamin A.
Carotene
___________ is yellow-brown or black pigment produced by melanocytes in stratum basale. Stored in transport vesicles (melanosomes) and transferred to keratinocytes
Melanin
________________ produce and store melanin
Melanocytes
Skin color depends on ___________ production, not number of melanocytes
melanin
Blood vessels _______ from heat, skin reddens.
Blood flow
decreases, skin pales
dilate
____________ is bluish skin tint caused by severe reduction in blood flow or oxygenation
Cyanosis
Pituitary tumor is excess _______.
MSH
Addison’s disease is disease of the pituitary gland that
Skin _______________.
darkening
__________ is loss of melanocytes and loss of color
Vitiligo
Liver and kidneys convert vitamin D3 into _____________
which
Aids absorption of calcium and phosphorus
calcitriol
_____________________ is produced by glands (salivary and duodenum)
Epidermal Growth Factor (EGF)
Epidermal Growth Factor (EGF) is used in laboratories to grow __________________.
skin grafts
Functions of _______:
Promotes division of germinative
cells
Accelerates keratin production
Stimulates epidermal
repair
Stimulates glandular secretion
EGF
The ________________ consists of areolar tissue; Contains smaller capillaries, lymphatics, and sensory neurons; and has dermal papillae projecting between epidermal ridges
Papillary Layer
The __________________ consists of dense irregular connective tissue; contains larger blood vessels, lymphatic vessels, and nerve fibers; Contains collagen and elastic fibers; Contains connective tissue proper
Reticular Layer
________________ an inflammation of the papillary layer; Caused by infection, radiation, mechanical irritation, or chemicals (e.g., poison ivy); characterized by itch or pain
Dermatitis
Another name for the eponychium is ______________.
cuticle
__________________ are very strong, resist stretching but bend easily and provide flexibility
Collagen fibers
_________________ permit stretching and then recoil to original length and limit the flexibility of collagen fibers to prevent damage to tissue
Elastic fibers
_________________ is a network of arteries along the reticular layer
Cutaneous plexus
______________ is a capillary network from small arteries in papillary layer
Papillary plexus
_______________ is a capillary return deep to the papillary plexus
Venous plexus
______________ is damage to blood vessels resulting in “black-and-blue” bruising
Contusion
Functions of ____________:
Protects and insulates
Guards
openings against particles and insects
Is sensitive to very light touch
Hair
The base of a hair follicle is surrounded by sensory nerves called ___________________.
root hair plexus
_________________ lubricate the hair and control bacteria
Sebaceous glands
The ______________ produces hair matrix:
A layer of dividing
basal cells
Produces hair structure
Pushes hair up and out
of skin
hair bulb
In the Hair Shaft Structure the _____________ is the central core.
Medulla
in the Hair Shaft Structure the ____________ is the surface layer.
Cuticle
In the Hair Shaft Structure the _____________ is the middle layer.
Cortex
Medulla contains ____________ keratin
flexible soft
Cortex and cuticle contain _______________ keratin
stiff hard
____________ is not growing and is attached to an inactive follicle
Club hair
_____________ is soft, fine and covers body surface
Vellus hairs
________________ is heavy, pigmented hair on Head, eyebrows, eyelashes and other parts of body after puberty
Terminal hairs
_________________ discharge directly onto skin surface
Sebaceous follicles
_____________________ are found in armpits, around nipples, and groin and secrete products into hair follicles. They produce sticky, cloudy secretions and break down and cause odors
Apocrine Sweat Glands
Apocrine Sweat Glands are surrounded by _________________.
They
squeeze apocrine gland secretions onto skin surface in response to
hormonal or nervous signal.
myoepithelial cells
_____________________ are widely distributed on body surface,
especially on palms and soles. They are coiled, tubular
glands
that discharge directly onto skin surface
Merocrine (Eccrine) Sweat Glands
____________ sweat glands discharge a watery fluid onto the surface of the skin.
Merocrine
__________________ glands produce cerumen (earwax) that protect the eardrum.
Ceruminous
Autonomic nervous system (ANS) controls ______________ and ___________ sweat glands that work simultaneously over entire body.
sebaceous and apocrine
_____________ sweat glands are controlled independently and sweating occurs locally.
Merocrine
Nail production occurs in a deep epidermal fold near the bone called the ____________
nail root
Nail body the visible portion of the nail covers the ____________.
nail bed
______________ is the pale crescent at the base of the nail
Lunula
Skin beneath the distal free edge of the nail is the __________________.
hyponychium (onyx = nail)
________________ is the cuticle.
Eponychium
____________________ feels pressure or vibrations in the skin.
Lamellated (pacinian) corpuscle
Basal cell carcinoma begins in the ______________— a type of cell within the skin that produces new skin cells as old ones die off.
basal cells
_______________ is the layer that are eight to ten layers of keratinocytes bound by desmosomes. Contain dendritic (Langerhans) cells, active in immune response.
Stratum spinosum
The ________________ layer is a thinner and flatter where the cells start to die.
stratum granulosum
The thickest layer of epidermis is the __________________.
stratum corneum
_____________ is caused by a deficiency in calcium and vitamin D.
Rickets
______________ is when there is excess MSH (Melanocyte-stimulating hormone) which causes the skin to turn dark.
Pituitary tumor
_________________ causes you to turn darker without sunlight.
- A disease of the pituitary gland
Addison’s disease