Integumentary System Flashcards
What are the two principal parts of the Integumentary System?
Epidermis and Dermis
The superficial, thinner layer composed of epithelial tissue
Epidermis
The deeper, thicker layer composed of dense irregular connective tissue
Dermis
What are the specific functions of the skin?
Thermoregulation Protection from external environment Cutaneous sensation Excretion Synthesis of vitamin D Reservoir for blood Absorbs substances
Excretion: what does sweat eliminate?
some water, salts, CO2, ammonia, urea
What are some characteristics of thermoregulation?
Evaporation of sweat cools the skin
Increased blood flow to the skin promotes heat loss by radiation
Hair traps heat, thereby reducing heat loss in cold temperature
The epidermis is composed of?
Keratinized stratified squamous epithelium
What are the four major types of cells of the Epidermis?
Keratinocytes
Melanocytes
Langerhans Cells
Merkel Cells
What is keratin?
tough, fibrous protein that waterproofs the skin
What does keratin do?
helps protect the skin and underlying tissues from heat, microbes, and chemicals
Keratinocytes (a layer of the epidermis) are formed when?
New cells produced by mitosis become filled with keratin.
What produces the pigment melanin?
the organelle melanosome
What is melanin?
A brown-black pigment that contributes to skin color and absorbs damaging ultraviolet light
Projections from _________ extend between keratinocytes, and do what?
melanocytes
They transfer melanin granules to them
What do the melanin granules do?
Cluster over the nucleus on the side toward the skin surface, shielding nuclear DNA from UV light.
What synthesize melanin from the amino acid tyrosine in the presence of the enzyme tyrosinase?
Melanosomes of melanocytes
Melanosomes of melanocytes synthesize melanin from the amino acid _____ in the presence of the enzyme ______
Tyrosine
Tyrosinase
What participates in immune responses to microbes that invade the skin (immune cells)?
Langerhans Cells
Langerhans cells are a type of what kind of cell?
Dendritic
What resides in the deepest layer of the epidermis where they contact the flattened processes of tactile discs?
Merkel Cells
What are the tactile discs, a type of sensory cell, the merkel cells contact called?
Merkel discs
What functions in the sensation of touch?
Merkel cells and tactile discs
What are they layers of the epidermis?
Stratum Corneum Stratum Lucidum Stratum Granulosum Stratum Spinosum Stratum Basale
What is the deepest layer of the epidermis?
Stratum Basale
What is the Stratum Basale made up of?
Mostly keratinocytes, a few melanocytes and Merkel cells
Keratinocytes have what type of filaments? and they are called?
Intermediate filaments
Tonofilaments
What are tonofilaments composed of?
A protein that will later form keratin
What has 8-10 layers of keratinocytes and a few Langerhans cells?
Stratum Spinosum
Older cells in the stratum spinosum start to?
Flatten
True or False
Cells in the stratum spinosum are still alive and some divide
True
3-5 layers of flattened keratinocytes and is a transition between living cells and the more superficial dead cells
Stratum Granulosum
In the stratum granulosum, what release a waterproofing lipid solution?
Lamellar granules
What is stratum granulosum filled with?
Granules of keratin
These are only found on fingertips, palms of hands, soles of feet.
Stratum Lucidum
What has 3-layers of flattened dead keratinocytes filled with keratin?
Stratum Lucidum
What is the most superficial layers of the epidermis that has 25-30 layers of flattened, dead cells?
Stratum Corneum
What provides waterproofing in the stratum corneum?
Between cells, lipids for lamellar granules
This layer of cells in the epidermis, interior of cells contains mostly keratin. The cells are continuously sloughed off and replaced by cells from deeper strata.
Stratum Corneum
What is dense irregular connective tissue that contains collagen and elastic connective tissue?
Dermis
What are the contents of the dermis?
Blood vessels
Nerves
Glands; sebaceous (oil) and sudoriferous (sweat)
Hair follicles
Arrectores pilorum muscles (singular is arrector pili)
What are the two components of the dermis?
Papillary region
Reticular region
What is the superficial part of the dermis?
Papillary region
What greatly increase the surface area of the papillary region? Why?
Dermal papillae
Gives better adhesion to epidermis
More surface area for diffusion to and from epidermis
What receptors are present in the papillary region of the dermis?
Touch corpuscles (Meissner corpuscles) for touch/light touch
What are touch corpuscles?
Free nerve endings with no apparent structural specialization that give rise to sensation of warmth, coolness, pain, tickle, itch
What consists of dense, irregular connective tissue containing bundles of collagen and some elastic fibers?
Reticular region of the dermis
The space between the fibers of the dermis are occupied but what?
Adipose cells Hair follicles Nerves Sebaceous (oil) glands Sudoriferous (sweat) glands
The combination of collagen and elastic fibers in the reticular region of the dermis provides?
the skin with strength, extensibility, and elasticity
What is the hypodermis?
Subcutaneous layer
What is the subcutaneous layer composed of ?
Areolar and adipose tissues
What does the subcutaneous layer contain?
Fat
Fibers that attach the dermis to deeper tissues
Larger blood vessels
Sensory receptors: Pacinian corpuscles (lamellated corpuscles)
What do Pacinian corpuscles sense?
Pressure
What are the epidermal ridges commonly called?
Fingerprints
What develops during the third and fourth fetal months as the epidermis conforms to the contours of the underlying dermal papillae of the papillary region?
Epidermal ridges (Fingerprints)
What do fingerprints do?
Increase the grip by increasing friction
What open on the tops of the epidermal ridges as sweat pores forming a pattern on smooth objects that are touched?
Ducts of sweat glands
What three pigments of varying amounts is the color of skin due to?
Melanin
Carotene
Hemoglobin
What determines the amount and expression of melanin and carotene?
Genetics
True or False
The number of melanocytes varies among different races
False
Exposure to UV light does what to the melanosomes?
the enzymatic activity
What gives the skin a tanned appearance and further protects the body against UV radiation?
Increased melanin production.
What is a yellow-orange pigment that is a precursor to vitamin A?
Carotene
What is used to synthesize pigments needed for vision?
Carotene
What causes the skin to appear pink?
when there is little melanin or carotene present, which allows the hemoglobin in the capillaries of the dermis to be expressed
What are the accessory structures of the skin?
Hair
Nails
Skin glands
In the dermis, what secrets sebum (oil) into a hair follicle?
Sebaceous glands
In the dermis, what duct extends through the epidermis?
Sweat glands
What is the superficial portion of the hair?
The shaft
What are the three layers of the hair shaft?
Medulla
Cortex
Cuticle
What is the downward continuation of the epidermis?
The external root sheath surrounding the root of the hair
What is hair composed of?
Dead, keratinized cells bonded by proteins
Where is the root of the hair located?
In the dermis
How does the hair grow?
Division of cells at the base of the hair follicle, new cells produced by mitosis in the hair matrix push the growing hair through the pilary canal.
What is the enlargement at the base of the hair follicle?
Bulb
What is the germinal layer of cells within the bulb called?
the matrix
Where does the matrix, in the bulb at the base of the hair follicle, arise from?
It is the site of what?
The stratum basale.
Site of cell division that produces the hair
What is associated with the hair?
Sebaceous (oil) glands
A bundle of smooth muscle called the arrector pili
Hair root plexuses
What causes goose bumps?
Autonomic nerve endings stimulate arrectores pilorum muscles to contract which causes goose bumps
A bundle of smooth muscle called the arrector pili helps regulate what?
Temperature and makes one look larger
What is the hair root plexus composed of?
Groups of dendrites and nerve fiber endings that form network around a hair follicle.
What does the hair root plexus act as?
A receptor to generate nerve impulses when hair shafts are moved.
In the category of hair, what acts like a fulcrum?
The shaft of the hair root plexus
In the category of hair, what is sensitive to touch, and movement of the hair shat?
Hair root plexus
What does each nail consist of?
Nail body
Free Edge
Nair root
What portion of the nail is visible?
Nail body
Why does the nail body appear pink?
Blood flowing through underlying capillaries
What is the whitish, crescent-shaped area of the proximal end of the nail?
The lunula
What are nails made of?
Tightly packed, hard, keratinized epidermal cells
What is the epithelium deep to the nail root called?
The nail matrix
How does the nail produce growth?
Cell of the nail matrix divide mitotically producing growth
What cells of the nail matrix are transformed into nail cells?
Superficial cells
The older harder cells of the nail matrix are pushed along the what toward the fingertip?
Stratum basale
What is sebum?
An oily substance that:
Keeps hair from drying
Prevents excessive evaporation of water from the skin
Inhibits growth of some bacteria
What are the two main types of sweat glands?
Eccrine sweat glands (Merocrine sweat glands)
Apocrine sweat glands
Where are the eccrine sweat glands (Merocrine sweat glands) found?
Found most places on the skin, function in thermoregulation
Where are apocrine sweat glands found?
Found in association with hair that develops at puberty
In what condition do the keratinocytes divide and move more quickly than normal from the stratum basale to the stratum corneum and are shed prematurely
Psoriasis
In Psoriasis what forms flaky, silvery scales at the skin surface most commonly on knees, elbows, and scalp (dandruff).
Immature keratinocytes that make an abnormal keratin
What are the three common forms of skin cancer?
Basal cell carcinomas (most common)
Squamous cell carcinomas
Malignant melanomas (least common, but most life-threatening)
What is the inherited inability of an individual to produce melanin, it is missing from their hair, eyes, and skin?
Albinism
In most cases, what is the cause of albinism?
The melanocytes are unable to synthesize tyrosinase
What is the partial or complete loss of melanocytes from patches of skin?
Vitiligo
What may be an autoimmune disorder in which the melanocytes are attacked and killed? There is also an apparent genetic link.
Vitiligo
What is cyanosis due to?
Hemoglobin that is depleted of oxygen looks deep, purplish blue.
Erythema is caused by engorgement of capillaries in the dermis with blood due to?
Skin injury Exposure to heat Infection Inflammation Allergic Reaction
What is Striae?
A form of scarring of the skin caused by tearing of the dermis. First appears as purple or reddish lines, but later fade to a lighter color.
What is Strae due to?
Result of rapid stretching of the skin due to rapid growth of puberty, weight gain, or pregnancy.
What can cause Alopecia?
Againg
Endocrine disorders
Chemotherapy
Skin diease
Inflammation of the skin characterized by redness, itching, and swelling, and caused by exposure of the skin to chemicals that bring about an allergic reaction
Contact Dermatits
What are the two types of wound healing?
Epidermal wound healing
Deep wound healing
What occurs following superficial wounds that affect only the epidermis and returns to normal function?
Epidermal wound healing
What occurs when an injury extends to the dermis and subcutaneous layer? Loss of some function and development of scar tissue is the rule.
Deep wound healing.
What are the steps of epidermal wound healing?
Basal cells at the margins of the wound break contact with the basement membrane and migrate
When basal cells contact each other, they stop migrating (contact inhibition)
Mitosis of basal cells is stimulated
Keratinocytes move up to form the more superficial layers
What are the stages of deep wound healing?
Inflammatory Phase
Migratory Phase
Proliferative Phase
Maturation Phase
What are the steps of the inflammatory phase of deep wound healing?
A blood clot forms and binds wound edges
Blood flow is increased, blood vessels become more permeable
WBCs and mesenchymal cells migrate to the area
What are the steps of the migratory phase of deep wound healing?
Epithelial cells migrate beneath the scab and bridge the wound
Fibroblasts migrate into the wound and begin to produce collagen fibers
What are the steps of the proliferative phase of deep wound healing?
Growth of epidermal cells beneath the scab
Increase in the amount of collagen
Regeneration of blood vessels
What are the steps of the maturation phase of deep wound healing?
Scab is lost
Collagen fibers become more organized, fibroblast numbers decrease, blood vessels are restored to normal.
Define- Tissue damage caused by excessive heat, electricity, radioactivity, or corrosive chemicals that destroy (denature) the proteins in the skin cells
Burn
What degree of burn involves only the epidermis, characterized by mild pain and erythema, but no blisters?
First degree burn
How long will it take a first degree burn to heal?
A few days and may be accompanied by flaking or peeling
What degree of burn destroys a portion of the epidermis and possibly parts of the dermis, characterized by pain, redness, blister formation, and edema? Some skin function are lost.
Second degree burns
How long does it take second degree burns to heal?
in a few (3-4) weeks, if there is no infection, scarring may result
What degree of burn destroys a portion of the epidermis as well as the underlying dermis and associated structures?
Third degree
Which degree of burn is marked edema, and the burned region is numb due to destruction of sensory nerve endings? Also termed full-thickness burn
Third degree
Which degree of burn are skin functions lost?
Third degree
An area where skin has been scraped away
Abrasion
A superficial fungal infection of the skin of the foot
Athlete’s foot
A collection of serous fluid within the epidermis or between the epidermis and dermis, due to short-term but severe friction
Blister
An area of hardened and thickened skin that is usually seen in palms and soles, and is due to persistent pressure and friction.
Callus
An inflammation of the skin characterized by patches of red, blistering, dry, extremely itch skin
Eczema
Medication applied to the skin surface, rather than ingested or injected
Topical
Mass produced by uncontrolled growth of epithelial skin cells; caused by a papillomavirus
Wart
Condition of excessive body hair
Hirsutism
Fine, nonpigmented, downy hairs that cover the body of the fetus
Laguno
Coarse, heavily pigmented hair; includes hair of the head, eyebrows, eyelashes, and hair that develops as a secondary characteristic.
Terminal Hairs
Short, fine, pale hairs that develop on most of the body during childhood
Vellus hairs
