A&P Chapter 5.1 Functional Anatomy of the Skin
stratum spinosum
Which layer of the epidermis contains dendritic (langerhans) cells?
stratum lucidum
Which layer of the epidermis means "clear layer"?
stratum granulosum
Which layer of the epidermis means "grainy layer"?
stratum spinosum
Which layer of the epidermis means "spiny layer"?
albinism
a disorder caused by the absence of melanin production (melanocytes lack the enzyme needed to produce melanin)
erythema
redness resulting from inflammation of sun-damaged tissue
epidermis
"thick" and "thin" refer to the relative thickness of just the ____________________, not the cutaneous membrane as a whole
status corneum
*outer layer of epidermis* that is at the exposed surface of both thick and thin skin; contains 15 to 30 layers of *keratinzed cells* and is *water resistant*
melanosomes
Pigment carrying granules that produce melanin, a complex protein.
paralell
A cut _______________ to a tension line will usually remain closed and heal with little scarring
rule of nines
A system that assigns percentages to sections of the body, allowing calculation of the amount of skin surface involved in the burn area.
fluid and electrolyte balance
Even areas with partial-thickness burns *lose effectiveness as barriers to* fluid and electrolyte loss
tension (cleavage) lines
Gaps found between collagen bundles in dermis create indentations in epidermis
Stratum corneum
In thick skin, what is the thickest (most cell layers) stratum of the epidermis?
Stratum basale and stratum spinosum
In which layers of the epidermis do mitotic divisions occur?
less
Light-skinned people produce (more/less) melanin than dark-skinned people
blood vessels, capillaries
Like all other epithelia, the epidermis lacks local _________________________ so they rely on __________________________
3rd
Loss of sensation and the absence of a reaction to a pin prick indicates the presence of a (1st/2nd/3rd) degree burn
melanin
Skin color differences are due to the amount of _______________ produced, not the number of melanocytes
keratinoyctes
The body's most abundant epithelial cells that dominate the epidermis, forming *strata* and are *continuously produced* in the deepest layers and *shed at the surface*
desmosomes
The dead cells in each layer of the stratum corneum are tightly interconnected by __________________
stratum basale
The deepest layer of the epidermis which is *attached to the basement membrane by hemidesmosomes* separating the epidermis from the dermis; dominated by *basal cells*
strata
The epidermis is composed of ______________ that have various functions
stratum granulosum
The layer of the epidermis that has *3-5 layers of keratinocytes* where *cells make keratin and keratohyalin*
Dense irregular connective tissue
The reticular layer of the dermis is composed of what kind of tissue?
cutaneous membrane
The skin made up of the *epidermis and the dermis*
dermis
This lies between the epidermis and the subcutaneous layer with *two types of fibers* (collagen, and elastic) that tolerate stretching
sensible perspiration
Water loss due to secretion by sweat glands that *you can feel*
subcutaneous fat
What accumulates at the beginning of puberty
1. fluid and electrolyte balance 2. thermoregulation 3. protection from infection
What are the 3 skin functions affected by burns?
carotene and melanin
What are the primary pigments involved in skin coloration?
Areolar and adipose
What are the primary tissues comprising the hypodermis?
epidermis, dermis, hypodermis
What are the three layers of the skin from external to internal?
free nerve endings, tactile discs
What are the touch receptors found in the epidermis?
tactile corpuscles, lamellar corpuscles, bulbous corpuscles
What are the touch receptors found tin the dermis?
circulation and pigment concentration
What are the two basic factors that interact to produce skin color?
dermis and epidermis
What are the two layers of the cutaneous membrane (skin)?
papillary, reticular
What are the two layers of the dermis?
cutaneous membrane, accessory structures
What are the two main parts of the integumentary system?
stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum
What is the correct order of strata from the basement membrane to the free surface of the epidermis?
hypodermis
What is the subcutaneous layer that separates the integument from the deep fascia around other organs?
keratin
What is the water-resistant, fibrous protein that fills the cells of the outer layers of the epidermis and helps slow dehydration?
third-degree burn
What type of burn is this?: the skin cannot repair itself because granulation tissue cannot form and epithelial cells are unable to cover the injury; *needs skin grafting*
second-degree burn
What type of burn is this?: the skin is blistered, painful, and swelling and takes 1-2 weeks to heal
first-degree burn
What type of burn is this?: the skin is red and painful
pale
When blood supply is temporarily reduced, the skin may become _____________.
flushed
When your vessels are dilated, the bright red oxygen-bound hemoglobin in the blood causes the skin to become _______________________.
Stratum lucidum
Which epidermal layer is found only in thick skin?
stratum corneum
Which epidermal stratum is the most superficial and is composed of 15-30 layers of dead, keratinized cells that eventually are shed from its surface?
lipids
Which of the following does the integument not synthesize or produce?
melanin
Which of the following is a dark brown, yellow-brown, or black pigment produced by pigment cells in the stratum basale?
hypodermis
Which of the following layers is composed of adipose and areolar tissues and is the site where subcutaneous injections are given?
keratinocytes
Which type of cell is the most abundant epithelial cell in the body and dominates the cellular composition of the epidermis?
A cut parallel to a cleavage line will remain closed.
Why are lines of cleavage clinically significant?
skin
_________ cancers are the most common types of cancer
metastasis
____________________ virtually never occurs in basal cell carcinomas, so most people survive
tactile disc
a Merkel cell along with a sensory nerve terminal
cyanosis
a bluish discoloration of the skin resulting from declining oxygen levels that causes hemoglobin to turn a darker red
melanin
a brown, yellow-brown, or black pigment produced by melanocytes
first-degree burn
a burn in which only the *surface of the epidermis is affect* (ex. a sunburn)
second-degree burn
a burn in which the *entire epidermis* and *maybe some of the dermis* are damaged
third-degree burn (full-thickness)
a burn that *destroys the epidermis and dermis* and *extends to the subcutaneous layer*; less painful than second-degree because *sensory nerves are destroyed
malignant melanoma
a condition in which cancerous melanocytes grow rapidly and metastasize through the lymphatic system
at a right angle
a cut _______________________ to a a tension line will be pulled open as severed elastic fibers recoil, resulting in scarring
subcutaneous layer
a layer *NOT apart of the skin* that separates the skin from deeper structures and permitting independent movement; dominated by *adipocytes* which have *fats that store energy*
stratum spinosum
a layer of the epidermis consisting of *8-10 layers of keratinocytes* bound by *desmosomes* and containing *dendritic cells*
stratum lucidum
a layer of the epidermis found only in the thick skin of the fingers, palms, and soles filled with *keratin and keratohyalin* and separates the stratum corneum from the deeper layers
autograft
a patients *own undamaged skin* used in a skin graft
split-thickness graft
a skin graft involving the transfer of the *epidermis and superficial portions of the dermis*
skin graft
a surgical procedure in which areas of intact skin are transplanted to cover the site of a burn
central adiposity
an excessive amount of abdominal fat that is strongly correlated with cardiovascular disease
carotene
an orange-yellow pigment that normally accumulates in epidermal cells; most apparent in the stratum corneum of light-skinned poeple and in vegetables
xenograft
animal skin used in a skin graft
20
burns that cover more than _______% of the skin threaten critical homeostatic functions of the skin
merkel cells
cells involved with touch sensations that are scattered among the basal cells
melanocytes
cells located in the stratum basale that manufacture melanin from the amino acid tyrosine and package it in vesicles called melanosomes
Dendritic (Langerhans) cells
cells which participate in the immune response by stimulating a dense against microorganisms that manage to penetrate the superficial layers of the epidermis and superficial skin cancers
accessory structures
components with supporting functions in the skin
dermis
the *middle layer of skin* that consist of a papillary layer and reticular layer
dermal papillae
dermal projections that project into the epidermis; *increase surface area for attachment* and *bind epidermis to the dermis*
allograft
frozen skin from a cadaver used in a skin graft
thermoregulation
increased fluid loss causes *increased cooling by evaporation* so more energy is expended to maintain body temperature
insensible perspiration
interstitial fluid lost by evaporation through the stratum corneum that you are *unable to feel*
stratum lucidum, stratum granulosum
keratohyalin is found in the ____________________________ and ________________________.
integument
skin
basal cells
stem cells whose divisions replace the more superficial keratinocytes that are lost or shed at the epithelial surface
subcutaneous layer
the *innermost layer of the skin* that separates the integument from the fascia around deeper organs *(NOT part of the integument)*
basal cell carcinoma
the *most common* form of skin cancer; originates in the stratum basale resulting from *mutations from overexposure to UV radiation*
epidermis
the *outermost layer of skin* consisting of a stratified squamous epithelium
subcutaneous
the _____________________ layer connects the dermis to underlying tissues
reticular layer
the bottom layer of the dermis consisting of an interwoven meshwork of *dense irregular connective tissue* containing both *collagen* and *elastic* fibers; contain blood and lymphatic vessels and nerve fibers
epidermal ridges
the deeper layers of the epidermis which extend into the dermis; *increase surface area for attachment* and *bind epidermis to the dermis*
keratinization
the formation of a protective, superficial layer of cells filled with keratin
reticular layer
the innermost layer of the dermis consisting of dense irregular connective tissue
papillary layer
the layer of the dermis that consists of *highly vascularized areolar tissue*, containing capillaries, lymphatic vessels and sensory nerve fibers
integumentary system
the most accessible and often the least appreciated organ system, making up 16% of your total body weight; your body's *first line of defense* against the environment
cutaneous plexus
the network of arteries and veins connected to smaller vessels servicing the tissues of the integumentary system
papillary layer
the outermost layer of the dermis consisting of areolar tissue
lamellar (pacinian) corpuscles
these are sensitive to *deep pressure and vibration*; found in *dermal layers* and *subcutaneous layer*
Bulbous (Ruffini) corpuscles
these are sensitive to *pressure and stretching of skin*; round in *reticular layer of the dermis*
free nerve endings
these are sensitive to touch and pressure, *found between epidermal cells*
tactile (meissner) corpuscles
these detect sensations of *delicate touch, pressure and vibration*; found in the *papillary layer of the dermis*
tactile discs
these detect sensations of *texture* and *steady pressure*; found in the *deepest layer of the epidermis*
subpapillary plexus
this lies *deep to the papillary layer* of the dermis and is a network of *blood vessels that supplies blood to capillaries* that provide oxygen and nutrients to the dermis and epidermis
thin skin
this skin covers most of the body surface, containing *4 strata*
thick skin
this skin is found on the *palms of your hands* and the *soles of feet* and has a *fifth stratum*
stratum basale
which layer of the epidermis contains basal and Merkel cells?
because the patient's immune system will reject them within 7-21 days
why are allografts and xenografts only temporary?
there are no vital organs and capillaries are sparse
why is the subcutaneous layer a common site for injections with hypodermic needles?
sepsis
widespread bacterial infection that is the leading cause of death in burn victims
