The integumentary system Flashcards
The integument is made up of two parts:
-cutaneous membrane (skin)
-accessory structures
True or False:
The integument is the largest system of the body at 16% body weight.
TRUE
What two parts make up the cutaneous membrane?
-outer epidermis
-inner dermis
Accessory structures:
-originate in the dermis
-extend through the epidermis to skin surface
Circulatory system (connection to integumentary)
contain blood vessels within the dermis
Nervous system (connection to integumentary)
Responsible for sensory receptors for pain, touch, and temperature
Subcutaneous layer
also known as the hypodermis, is the deepest layer of skin, located below the dermis and closest to the muscles.
It’s made up of fat, connective tissue, blood vessels, and nerves.
What are 6 important functions of the skin
-protects
-excretes
-maintains body temp
-synthesizes
-stores lipids
-detects
Keratinocytes
-contain large amounts of keratin
-most abundant cells in the epidermis
Thick skin:
-covers the palms of the hands and soles of the feet
-has 5 layers of keratinocytes
Thin skin:
-covers most of the body
-has 4 layers of keratinocytes
What are the layers of strata from basal lamina to free surface?
-stratum basale
-stratum spinosum
-stratum granulosum
-stratum lucidum
-stratum corneum
The “Basale layer”
AKA germinative layer
-has many germinative (stem) cells or basal cells
-attached to basal lamina by hermidesmosomes
-forms a strong bond between epidermis and dermis
What are the two structures of the
basale
aka germinativum
-epidermal ridges
-dermal papillae
Epidermal ridges
fingerprints
Dermal papillae
strengthen attachment between epidermis and dermis
Merkel cells
-found within hairless skin and respond to touch
Melanocytes
scattered throughout stratum germinativum and contain melanin
Stratum spinosum AKA “spiny layer”
-produced by division of stratum germinosum
-8-10 layers or keratinocytes bound by desmosomes
Stratum granulosim:
stops dividing and starts producing keratin and keratohyalin
Keratin
tough, fibrous protein that makes up hair and nails
Cells of the stratum granulosum:
-produce protein fibers
-dehydrate and die
Stratum lucidum:
found only in thick skin
-flat, dense, and filled with keratin
Stratum corneum
-exposed surface of skin
-15-30 layers of keratinized cells
-water resistant
-shed and are replaced q2w
Keratinization
the formation of a layer of dead, protective cells filled with keratin
- on all exposed skin surfaces except eyes
Skin life cycle
15-30 days from germinosum to cornerum
Insensible perspiration
Interstitial fluid lost by evaporation through the stratum corneum
Sensible perspiration
water excreted by sweat glands
Dehydration results on skin
-comes from damage to stratum corneum
-from immersion in hypertonic solution ex: salt water
Hydration (regarding skin)
-Results from immersion in hypotonic solution ex: freshwater
-causes stretching and wrinkling of skin
Skin color depends on:
melanin and carotene
melanin production, not # of melanocytes
Melanin
-yellow, brown or black pigments
-produced by melanocytes
-stored in transport vesicles
Carotene
-orange-yellow pigment
-found in orange vegetables
Cyanosis
bluish skin tint caused by severe reduction in blood flow or oxygen
Jaundice
buildup of bile produced by liver giving skin yellow color
Vitiligo
loss of melanocytes resulting in loss of color
Nevus
mole
Angle’s kiss
located on forehead and eyelids, usually disappear by age 2
Stork bite
marks on the back of neck that may result into adulthood
infantile (strawberry) hemangioma
-most common birth mark
Capillary malformation (port-wine stain)
flat, pink red, or purple mark that appears at birth and continues to grow as the child does
Vitamin D is produced by:
epidermal cells
Epidermal growth factor (EGF)
produced by gland
used in laboratories to grow skin grafts
powerful peptide growth factor
Where is the dermis located?
between epidermis and subcutaneous layer
The reticular layer:
-consists of dense irregular connective tissue, collagen, and connective tissue proper
-contains larger blood vessels, lymph vessels, and nerve fibers
The papillary layer
-consists of areolar tissue
-contains capillaries, lymphatics, and sensory neurons
Dermatitis
inflammation of the papillary layer caused by infection, radiation, mechanical irritation, or chemicals
Lines of cleavage
establish important patterns on body that determine if cuts heal well or not
Cutaneous artery
a network of arteries along the reticular layer
Papillary plexus
capillary network from small arteries in papillary layer
venous plexus
a network of veins located in the deep dermis
Contusion
damage to blood vessels resulting in bruising
Subcutaneous layer or hypodermis
-lies below the integument
-stabilizes the skin
-allows separate movement
Adipose tissue
-have distribution pattern determined by hormones
-can be reduced by cosmetic liposuction
the human body is covered in hair EXCEPT:
palms, soles, lips, portions of external genitalia
Hair follicles are:
-located deep in dermis
-produces nonliving hairs
-wrapped in a dense connective-tissue sheath
-base is surrounded by sensory nerves (root hair plexus)
Arrector pili
-involuntary smooth muscle
-causes hair to stand up
-produces “goose bumps”
Sebaceous gland
lubricates the hair and controls bacteria
Hair root
-lower part of the hair
-attached to the integument
Hair shaft
-upper part of the hair
-not attached to the integument
Hair papilla
supplies the dividing hair cells in the hair matrix with the necessary nutrients
Hair bulb
lowest part of the hair strand
Hair Matrix
contains the proliferating cells that generate the hair and the internal root sheath
Medulla (hair)
the central core
Cortex (hair)
the middle layer
Cuticle (hair)
the surface layer
internal root sheath (layers in the follicle)
-the inner layer
-contacts the cuticle in lower hair root
external root sheath (layers in the follicle)
extends from skin surface to hair matrix
glassy membrane (layers in the follicle)
-dense connective tissue sheath
-contacts connective tissues of dermis
Growing hair is
firmly attached to the matrix
Club hair is
-not growing
-attached to an inactive follicle
Lanugo
fetal hair follicles
Vellus hairs
soft, fine, and covers most of the body surface
Terminal hairs
heavily pigmented and located on head, eyebrows, and genitalia after puberty
Hair color is produced by:
melanocytes at the hair papilla moved into the hair matrix and determined by genes
Simple branched alveolar glands
a gland with a simple duct and branched alveolar sacs
sebaceous follicles
discharge directly onto skin surfaces through holocrine glands and sebum secretion
Where are apocrine glands located?
armpits, around nipples, and groin
associated with hair follicles
break down and cause odors
Where are merocrine glands located?
widely distributed on body surface especially on palms and soles
Cereminous glands
protect the eardrum and produce cerumen (ear wax)
Nails
made up of dead cells packed with keratin and can be changed by metabolic disorders
Nail root
the part of the nail that grows from the nail bed and extends into the finger, located underneath the skin and nail
Nail body
he visible hard nail area from the nail root to the free edge, made of translucent keratin protein
Lunula
Pale crescent at base of the nail
1st degree burn
epidermis is damaged
2nd degree burn
epidermis and upper dermis damanged
3rd degree burn
entire thickness of skin
