Chapter 5 - Integumentary System Flashcards
forms the boundary
between the body and the external environment,
integumentary system
major functions of the integumentary system (5)
- Protection
- Sensation
- Temperature regulation
- Vitamin D production
- Excretion
The skin is made up of two major tissue layers:
epidermis
dermis
the superficial layer of the skin, consisting of stratified
squamous epithelial tissue
epidermis
Function of epidermis’ multiple layers
resists abrasion on the skin’s surface and reduces water loss through the skin
a layer of connective tissue
dermis
responsible for most of the strength of the skin.
e structure of the dermis
produced from the hide (skin) of
an animal by removing the epidermis and preserving the dermis in a process called tanning
leather
a layer of loose connective tissue
subcutaneous tissue, or hypodermis
not part of the skin or the integumentary
system, but it does connect the skin to underlying muscle or bone.
subcutaneous tissue, or hypodermis
contains no blood vessels
epidermis
what separates epidermis from dermis?
basement membrane
The living cells of the epidermis receive nutrients and excrete waste products through what?
Diffusion (of substances between the epidermis and
the capillaries of the dermis)
Most cells of the epidermis are called
keratinocytes
produce a protein mixture called keratin
keratinocytes (makes the cells more durable)
give the epidermis its ability to resist abrasion and
reduce water loss
keratinocytes
Other cells of the epidermis (3)
melanocytes
Langerhans cells
Merkel cells
produce the pigment melanin, which contributes to skin color
melanocytes
are part of the immune system
Langerhans cells
are specialized epidermal cells associated with
the nerve endings responsible for detecting light touch and superficial pressure
Merkel cells
When are new keratinocytes produced?
when keratinocyte stem cells undergo mitosis in the deepest layer of the epidermis.
process of where the cells eventually die and produce an
outer layer of dead, hard cells that resists abrasion and forms a permeability barrier
keratinization
many layers of cells in the epidermis are divided
into regions, or
strata
Five strata of the epidermis:
stratum basale
stratum spinosum
stratum granulosum
stratum lucidum
stratum corneum
the deepest portion of the epidermis is a single layer of cuboidal or columnar cells called the
stratum basale
the deepest portion of the epidermis is a single layer of cuboidal or columnar cells called the
stratum basale (stratum germinativum)
The epidermis is anchored to the basement membrane by what?
hemidesmosomes.
hold the keratinocytes together
desmosomes
Keratinocytes are strengthened internally by what?
Keratin fibers
Keratinocyte stem cells
of the stratum basale undergo mitotic divisions approximately every how many days?
19 days
It takes approximately how many days
for the cell to reach the epidermal surface and slough off?
40–56 days
Superficial to the stratum basale
stratum spinosum (consisting of 8–10 layers of many-sided cells)
As the cells in this stratum are pushed to
the surface, they what?
flatten
What additional keratin fibers and lipid-filled, membrane-bound organelles form inside the keratinocyte?
lamellar bodies
consists of two to five
layers of somewhat flattened, diamond-shaped cells.
stratum granulosum
stratum granulosum derives its name from the
presence of protein granules of?
keratohyalin
Keratohyalin accumulates in what part of the cell?
cytoplasm
a thin, clear zone above the
stratum granulosum
stratum lucidum
consists of several layers of dead cells with indistinct boundaries.
stratum lucidum
present in only a few areas of the body
stratum lucidum
last, and most superficial, stratum of the epidermis
stratum
corneum
composed of 25 or more layers of dead, overlapping squamous cells
joined by desmosomes.
stratum
corneum
dead cells, with a hard protein envelope, filled with the protein keratin.
cornified cells
responsible for the structural strength of
the stratum corneum.
enveloped and the keratin
The type of keratin found in the skin
soft
keratin
found in nails and
the external parts of hair
hard keratin
Cells containing __ are more
durable than cells with soft keratin, and they are not shed
hard keratin
What are released from lamellar bodies surrounding the skin
cells?
lipids
responsible for many of the skin’s permeability characteristics.
lipids
has all five epithelial strata, and the stratum corneum
has many layers of cells.
thick skin
found in areas subject to
pressure or friction, such as the palms of the hands, the soles of
the feet, and the fingertips.
thick skin
covers the rest of the body and is more flexible
than thick skin.
thin skin
Each of its strata contains fewer layers of cells
than are found in thick skin; the stratum granulosum frequently
consists of only one or two layers of cells, and the stratum lucidum
is generally absent
thin skin
found only in what kind of skin?
thin skin
often forms when the stratum corneum of the
epidermis increases in thickness.
callus
The skin over bony prominences develop a
cone-shaped structure called a
corn
the group of pigments primarily
responsible for skin, hair, and eye color.
melanin
provides
protection against ultraviolet light from the sun.
melanin
found in certain regions of the skin, such as freckles,
moles, the nipples, the areolae of the breasts, the axillae, and the
genitalia
Large amounts of
melanin
contain less melanin
lips, palms of the
hands, and soles of the feet,
Melanin is produced by?
melanocytes
irregularly shaped cells with many long processes that extend between the
keratinocytes of the stratum basale and the stratum spinosum
melanocytes
Melanocytes produce and package melanin into vesicles
called
melanosomes
only cells that produce melanin
melanocytes
a recessive genetic trait that results
from an inability to produce tyrosinase.
albinism
most common type of
cancer
skin cancer
three types of skin cancer:
basal cell carcinoma
squamous cell carcinoma
melanoma
most common type, affects cells in the
stratum basale
Basal cell carcinoma
affects cells in the stratum
spinosum and can appear as a wartlike growth
Squamous cell carcinoma
is the least
common, but most deadly, type of skin cancer,
accounting for over 77% of the skin cancer
deaths in the United States.
melanoma
What causes the mother’s body to increase melanin production?
estrogen and
melanocyte-stimulating hormone
a condition in which the skin turns
a reddish hue when the amount of blood flowing through the skin
increases.
Erythema
a bluish skin color
cyanosis
a yellow pigment found in plants,
such as carrots and corn
carotene
a lipid-soluble and, when
large amounts are consumed, the excess accumulates
in the stratum corneum and in adipocytes of the dermis and subcutaneous tissue, causing the skin to develop a yellowish tint
carotene
The cells of the dermis:
fibroblasts
adipocytes
macrophages
the main type of protein fiber of the extracellular
matrix
collagem
the main type of protein fiber of the extracellular
matrix
collagen (but elastic and reticular fibers are also present)
contains blood vessels that allow for nutrient and waste exchange
to the cells of the dermis and the living cells of the epidermis.
dermis
contains nerve endings, hair follicles, smooth muscles,
glands, and lymphatic vessels
dermis
The dermis is composed of two tissue layers:
papillary layer
reticular layer
The papillary layer derives its name
from projections, called
dermal papillae (extend
toward the epidermis)
loose connective
tissue with thin fibers that are somewhat loosely arranged.
papillary layer
contains blood vessels that supply the overlying epidermis with oxygen and nutrients, remove waste products,
and aid in regulating body temperature
papillary layer
composed of dense irregular
connective tissue, is the main layer of the dermis.
reticular layer
continuous with the subcutaneous tissue and forms a mat of irregularly arranged fibers that are resistant to stretching in many directions.
reticular layer
tension lines in the skin produced by elastic and collagen fibers
cleavage lines
If the skin is overstretched, the dermis may rupture and leave
lines that are visible through the epidermis. These lines of scar
tissue, called
stretch marks
attaches the skin to underlying bone and muscle and supplies
the skin with blood vessels and nerves
subcutaneous tissue
consists of loose connective tissue with collagen
and elastic fibers.
subcutaneous tissue
The main types of cells within the subcutaneous
tissue:
fibroblasts
adipocytes
macrophages
The subcutaneous tissue, which is not part of the skin, is sometimes called
hypodermis
Approximately half the body’s stored lipids are in the?
subcutaneous tissue
three types of injections:
intradermal injection (dermis)
subcutaneous injection (subcutaneous tissue) ex. insulin injection
intramuscular injection (reaches a muscle
deep to the subcutaneous tissue) ex. vaccine shots
one of the characteristics of all mammals
presence of hair
dense and covers most of the body surface
fur
unpigmented
hair in fetus
lanugo
long, coarse, and pigmented hairs near the time of birth
terminal hairs
short, fine, and usually
unpigmented, replace the lanugo on the rest of the body
vellus hairs
The % of hair of the chest, legs, and
arms in male and female
90% terminal hair in males
35% in females
protrudes above the surface
of the skin
hair shaft
located below the surface
root
The base of the root is expanded to form the
hair bulb
Most of the
root and the shaft are composed of columns of dead, keratinized
epithelial cells arranged in three concentric layers:
medulla
cortex
cuticle
central axis of the hair
medulla (cells contain soft keratin)
surrounds the medulla
and forms the bulk of the hair
cortex (contain hard keratin)
a single layer
of cells also containing hard keratin.
cuticle
a tubelike invagination of the epidermis
that extends into the dermis.
hair follicle
A hair follicle consists of:
dermal root sheath
epithelial root sheath
the portion of the dermis that surrounds the epithelial root sheath.
dermal root sheath
divided into external and internal parts
epithelial root sheath
Inside the hair bulb is a mass of undifferentiated epithelial cells called the
matrix
produces the hair
and the internal epithelial root sheath.
matrix
The dermis of the skin
projects into the hair bulb as a
hair papilla
stages of hair growth (2)
growth stage
resting stage
most common kind of permanent hair loss
pattern baldness
average rate of hair growth
0.3 mm per day
within the hair bulb matrix, produce melanin and pass it to keratinocytes in the hair cortex and medulla.
melanocytes
Associated with each hair follicle are smooth muscle cells called
arrector pili
extend from the dermal root sheath of the hair follicle to the papillary layer of the dermis
arrector pili
muscle cells responsible for goosebumps
arrector pili
major glands of the skin
sebaceous glands
sweat glands
located in the dermis, are simple
or compound alveolar glands that produce sebum
Sebaceous Glands
an oily, white substance rich in lipids
sebum
(T/F) Because sebum is released by
the lysis and death of secretory cells, sebaceous glands are classified as holocrine glands
true
two types of sweat, or sudoriferous glands:
eccrine glands
apocrine glands
or merocrine, are the most common type of sweat gland. They are simple, coiled, tubular glands that open directly onto the surface of the skin through sweat pores
eccrine sweat glands
Eccrine sweat glands can be divided into
two parts:
deep or coiled portion (located mostly in the
dermis)
duct (which passes to the skin surface)
produces an isotonic fluid that is mostly water but
also contains some salts (mainly sodium chloride) and small
amounts of ammonia, urea, uric acid, and lactic acid.
deep or coiled portion
The resulting hyposmotic fluid that leaves the duct is called
sweat
most numerous in the palms of the
hands and soles of the feet
eccrine
simple, coiled, tubular
glands that usually open into hair follicles superficial to the opening of the sebaceous glands
apocrine sweat galnds
found in the axillae and genitalia (scrotum and labia majora)
and around the anus.
apocrine
do not help regulate temperature in humans.
apocrine
become active at puberty as a result of sex hormones.
and their secretions contain organic substances
apocrine
Other skin glands (2)
ceruminous glands and the mammary
glands
modified eccrine sweat glands located in the ear canal (external auditory canal).
ceruminous glands
composed of the combined secretions
of ceruminous glands and sebaceous glands
cerumen or earwax
modified apocrine sweat glands
located in the breasts that produce milk.
mammary glands
a thin plate consisting of layers of dead stratum corneum
cells that contain a very hard type of keratin.
nails
located on
the distal ends of the digits
nails
A nail consists of
the proximal __ and the distal __
nail root; nail body
covered by skin,
nail root
the visible portion
of the nail
nail body
The lateral and proximal edges of the nail are covered
by skin called the
nail fold
the edges are held in place by the
nail groove
a thickened region of the stratum
corneum beneath the free edge of the nail body
hyponychium
The nail root extends distally from the
nail matrix
s located between
the nail matrix and the hyponychium.
nail bef
s located between
the nail matrix and the hyponychium.
nail bed
seen through the nail body as a whitish crescent-shaped area at the base of the nail.
lunula
why does lunula appear white?
because the blood vessels do not
show through the thicker nail matrix
the most common type of freezing injury. When skin
temperature drops below 0°C (32°F), the skin freezes and ice crystal formation damages tissues.
frostbite
a hormone involved in the regulation of
calcium homeostasis.
vitamin D
Its primary role is to stimulate the uptake
of calcium and phosphate from the intestines.
vitamin D
itamin D synthesis begins in skin exposed to what?
Ultraviolet light
the removal of waste products from the body.
excretion
injury to a tissue caused by heat, cold, friction, chemicals,
electricity, or radiation.
burns (classified according to the extent
of surface area involved and the depth of the burn. )
“the rule of nines,”
divides the body into areas that are approximately 9%, or multiples of 9%, of the body surface area (in an infant, the head and neck are 21% of BSA)
burns are classified as either:
partial thickness or full-thickness burns
subdivided into first- and second-degree burns
Partial-thickness burns
involve only the epidermis and may result in redness, pain, and slight edema (swelling).
first-degree burns
caused by sunburn or brief exposure to hot or cold objects, and they heal in
a week or so without scarring.
First-degree burns
damage the epidermis and dermis.
second-degree burns (Healing takes approximately 2 weeks, and no scarring results)
ull-thickness burns are also called as
third-degree burns
The epidermis and dermis are completely destroyed, and deeper
tissue may be involved.
third-degree burns (often surrounded
by first- and second-degree burns)
its region is usually painless because the sensory receptors
have been destroyed.
third-degree burn
a third-degree burn over
10% or more of the BSA; a second-degree burn over 25% or more of the BSA; or a second- or third-degree burn of the hands, feet, face, genitals, or anal region
major burn
e often associated with
damage to the respiratory tract and burns of joints often heal with scar tissue formation that limits movement.
facial burns
a third-degree burn over 2–10% of the BSA or a second-degree burn over 15–25% of the BSA.
moderate burn
a third-degree burn over
less than 2% or a second-degree burn over less than 15% of the BSA.
minor burn
vitamin A derivative that
appears to be effective in treating fine wrinkles on the face, such
as those caused by long-term exposure to the sun; it is not effective in treating deep lines.
Retin-A (tretinoin)
Causes skin to sag and wrinkle
A decrease in the number of elastic fibers in the dermis
and a loss of adipose tissue from the subcutaneous tissue
Congenital (present at birth) disorders of the dermal capillaries
Birthmarks
Fungal infection that produces patchy scaling and inflammatory response in the skin
Ringworm
Inflammatory conditions of the skin caused by allergy, infection, poor circulation, or exposure to chemical or
environmental factors
eczema and dermatitis
Chronic skin disease characterized by thicker than normal epidermal layer (stratum corneum) that sloughs to
produce large, silvery scales; bleeding may occur if the scales are scraped away
psoriasis
Development of patches of white skin where melanocytes are destroyed, apparently by an autoimmune response
vitiligo
result in destruction of the skin and subcutaneous tissue, which later become infected by bacteria, forming ulcers
Acne Disorder of sebaceous glands and hair follicles that occurs when sloughed cells block the hair follicle, resulting in
the formation of a lesion or pimple.
acne
compression of tissue and reduced circulation
result in destruction of the skin and subcutaneous tissue, which later become infected by bacteria, forming ulcers
Decubitus ulcers (bedsores,
pressure sores)
Swollen patches in the skin caused by the bacterium Streptococcus pyogenes
Erysipelas
Small blisters containing pus; easily rupture to form a thick, yellowish crust; usually affects children
impetigo
caused by a virus contracted through the respiratory tract; may develop into pneumonia or infect
the brain, causing damage
Rubeola (measles)
Skin lesions; usually mild viral disease contracted through the respiratory tract; may be dangerous if contracted
during pregnancy because the virus can cross the placenta and damage the fetus
Rubella (German measles)
Skin lesions; usually mild viral disease contracted through the respiratory tract
Chickenpox
Painful skin lesions; caused by the chickenpox virus after childhood infection; can recur when the dormant virus
is activated by trauma, stress, or another illness
Shingles
Skin lesions; caused by herpes simplex I virus; transmitted by oral or respiratory routes; lesions recur
Cold sores (fever blisters)
Genital lesions; caused by herpes simplex II virus; transmitted by sexual contact
Genital herpes
