Flashcards in 3 Veterinary Term: The Integumentary System Deck (155):
What is the INTEGUMENTARY SYSTEM of the body?
The skin and its accessory organs (hair, nails, hooves, claws and glands)
What does Integument mean?
means covering, and the skin is the outer covering for the body
At does the Integument contain?
glands that secrete several types of fluids.
nerves that carry impulses.
blood vessels that aid in the regulation of temperature.
As a protective membrane over the entire body, the skin guards what?
guards the deeper tissues of the body against excessive loss of water, salts and heat and against invasion of pathogens and their toxins.
What contributes to the skin’s ability to prevent bacterial invasions?
Secretions from the skin that are slightly acidic in nature
What do Specialized cells (LANGERHANS CELLS) do?
react to the presence of antigens and have an immune function.
What two types of glands does the skin contain that produce important secretions?
SEBACEOUS and SWEAT glands
What do SEBACEOUS glands produce?
SEBUM, an oily secretion
What do sweat glands produce?
sweat, a watery secretion
How does sebum and sweat pass through the skin?
pass to the outer edges of the skin through ducts and leave the skin through openings, or PORES
What is the function of sebum?
lubricates the surface of the skin
What is the function of sweat?
cools the body as it evaporates from the skin surface
Nerve fibers under the skin are receptors for what?
sensations such as pain, temperature, pressure and touch
The body’s adjustment to the environment depends on what?
sensory messages relayed to the brain and spinal cord by sensitive nerve endings in the skin.
Different tissues in the skin maintain what?
body temperature (THERMOREGULATION)
Nerve fibers coordinate THERMOREGULATION by?
carrying messages to the skin from heat centers in the brain that are sensitive to increases and decreases in body temperature. Impulses from these fibers cause blood vessels to dilate to bring blood to the surface and cause sweat glands to produce the watery secretion that carries heat away.
What are the three layers of the skin?
Subcutaneous layer (HYPODERMIS)
What is the EPIDERMIS?
a thin, cellular membrane layer containing keratin
What is the DERMIS?
dense, fibrous, connective tissue layer; containing collagen
What is the SUBCUTANEOUS LAYER (HYPODERMIS)?
thick fat-containing tissue
What is the epidermis composed of?
Epithelium is the covering of both the internal and the external surfaces of the body.
Describe Squamous epithelium?
cells are flat and scale-like.
In the outer layer of the skin, these cells are arranged in several layers (STRATA) to form STRATIFIED SQUAMOUS EPITHELIUM
What does the epidermis lack?
blood vessels, lymphatic vessels and connective tissue (elastic fibers, cartilage, fat)
What does the epidermis depend on?
dependent on the deeper dermis layer and its rich network of capillaries for nourishment.
Oxygen and nutrients seep out of the capillaries in the dermis, pass through tissue fluid and supply nourishment to the deeper layers of the epidermis.
What is the deepest layer of the epidermis?
Describe the cells of the basal layer?
cells in the basal layer are constantly growing and multiplying and give rise to all the other cells in the epidermis
What happens as the cells of the basal layer divide?
they are pushed upward and away from the blood supply of the dermal layer by a steady stream of younger cells
What is the most superficial layer of the epidermis?
As the cells move toward the STRATUM CORNEUM what happens?
the cells flatten, shrink, lose their nuclei and die, becoming filled with a hard protein material called KERATIN.
The cells are then called HORNY CELLS, reflecting their composition of keratin.
Within 3 to 4 weeks after beginning as a basal cell in the deepest part of the epidermis, the keratinized cell is?
sloughed off from the surface of the skin.
The epidermis is thus constantly renewing itself, cells dying at the same rate at which they are replaced.
What special cells does the basal layer of the epidermis contain?
What do MELANOCYTES form and contain?
a brown-black pigment called MELANIN that is transferred to other epidermal cells and gives color to the skin
The presence of MELANIN in the epidermis is vital for what?
protection against the harmful effects of ultraviolet radiation, which can manifest as skin cancer.
Individuals who are INCAPABLE of forming MELANIN are called?
Skin and hair are white.
Their pupils (circular opening in the eye) are red because in the absence of pigment in the retina, the tiny blood vessels are visible in the iris (normally pigmented portion) of the eye.
Melanin production increases with what?
exposure to strong ultraviolet light, and this creates a suntan, which is a protective response.
How does one become sunburned?
When the melanin cannot absorb all the UV rays, the skin becomes sunburned and inflamed (redness, swelling and pain).
The dermis is composed of?
blood and lymph vessels, and nerve fibers, as well as the accessory organs of the skin
What are the accessory organs of the skin?
the HAIR FOLLICLES, the sweat glands and sebaceous glands.
How does the dermis support the elaborate system of nerves, vessels and glands?
the dermis contains connective tissue cells and fibers that account for the extensibility and elasticity of the skin.
The dermis is composed of what kind of fibers?
interwoven elastic and COLLAGEN fibers.
What is COLLAGEN?
(COLLA means glue) is a fibrous protein material found in bone, cartilage, tendons and ligaments, as well as in the skin.
It is tough and resistant but also flexible.
Describe collagen in an infant
In the infant, collagen is loose and delicate; it becomes harder as the body ages.
What is the function of collagen?
Collagen fibers support and protect the blood and nerve networks that pass through the dermis.
Collagen diseases affect connective tissues of the body.
The epidermis and dermis are what layers of the skin?
The subcutaneous layer (HYPODERMIS) specializes in the formation of what?
What cells are predominant in the subcutaneous layer and what are their function?
Lipocytes (fat cells)
they manufacture and store large quantities of fat.
The subcutaneous layer of the skin is important functionally because?
important in protection of the deeper tissues of the body, as a heat insulator and for energy storage.
What are the accessory organs of the skin?
What is a hair fiber composed of?
tightly fused meshwork of cells filled with the hard protein called keratin.
Hair growth is similar to what?
the growth of the epidermal layer of the skin.
Deep-lying cells in the hair root produce what?
keratinized cells that move upward through hair follicles (sacs within which each hair fiber grows).
Melanocytes are located where and what do they do?
at the root of the hair follicle
and they donate the melanin pigment to the cells of the hair fiber.
What type of melanin is responsible for red hair?
A type of melanin containing iron
When does hair turn gray?
with advancing age the melanocytes stop producing melanin.
What are the types of hair follicles?
Single (simple) follicle
Describe a single (simple) hair follicle
one hair emerges from a single opening
found in horse, cattle, pig and sheep (face, ear, distal portion of limbs)
Describe a compound follicle
several hairs emerge from a single opening.
Found in cat, dog, sheep (wool growing areas).
Consists of a long principal (guard) hair and a number of smaller auxiliary (wool) hairs.
What are nails?
are hard keratin plates covering the dorsal surface of the last bone of each toe and finger.
What are nails composed of?
composed of HORNY CELLS that are cemented together tightly and can extend indefinitely unless cut or broken.
How does a nail grow?
A nail grows in thickness and length as a result of division of cells in the region of the nail root, which is at the base (proximal portion) of the nail plate.
What is a CUTICLE?
a narrow band of epidermis (layer of keratin), is at the base and sides of the nail plate.
What is the PARONYCHIUM?
is the soft tissue surrounding the nail border.
What happens during systemic disease?
Nail growth and appearance commonly alter.
For example, grooves in nails may occur with high fevers and serious illness.
What is ONYCHOLYSIS?
(oncych/o means nails) is the loosening of the nail plate with separation from the nail bed.
It may occur with infection of the nail.
Where are sebaceous glands located?
in the dermal layer of the skin over the entire body.
with the exception of the palms and soles.
Sebaceous glands secrete what?
an oily substance called sebum
What is the function of sebum?
Sebum, containing lipids, lubricates the skin and minimizes water loss.
Sebaceous glands are closely associated with what?
hair follicles, and their ducts open into the hair follicle through which the sebum is released.
sebaceous glands are influenced by?
sex hormones, which cause them to hypertrophy at puberty and atrophy in old age.
Sebum gives hair what?
What are sweat glands?
tiny, coiled glands found on almost all body surfaces.
Sweat glands are most numerously found where?
the palm of the hand and in the sole of the foot.
Where do sweat glands originate?
originates deep in the dermis and straightens out to extend up through the epidermis.
The tiny opening on the surface is a pore.
What is sweat made of?
almost pure water, with dissolved materials such as salt making up less than 1 percent of the total composition.
It is colorless and odorless.
The odor produced when sweat accumulates on the skin is caused by what?
by the action of bacteria on the sweat.
Sweat cools the body when?
as it evaporates in the air.
Sweating is controlled by what?
the SYMPATHETIC NERVOUS SYSTEM, whose nerve fibers are activated by the heart regulatory center in the HYPOTHALMIC region of the brain, which stimulates sweating.
What are the types of sweat glands?
ECCRINE Sweat Glands
APOCRINE Sweat Glands
What are ECCRINE Sweat Glands?
small glands that are widely distributed and produce a watery secretion; they are mainly a mechanism for cooling; restricted to foot pads of carnivores, frog of ungulates and nasolabial region of ruminants and swine.
What are APOCRINE Sweat Glands?
larger glands with cuboidal epithelium that produce oily and foamy secretions; most common in the groin, axilla and scrotum of dogs and cats; most numerous and extensive in horses. These are the most common type found in domestic animals.
individual with skin deficient in pigment (melanin)
Deepest region of the epidermis; it gives rise to all the epidermal cells
Structural protein found in the skin and connective tissue
Band of epidermis at the base and sides of the nail plate
Middle layer of the skin
Outermost layer of the skin
Layer of skin cells forming the outer and inner surfaces of the body
Sac within which each hair grows
The skin and its accessory structures such as hair and nails
Hard protein material found in the epidermis, hair and nails.
Keratin means horn and commonly is found in the horns of animals
A fat cell
Major skin pigment.
It is formed by melanocytes in the epidermis.
Soft tissue surrounding the nail border
Tiny opening on the surface of the skin
Oil-secreting gland in the dermis that is associated with hair follicles
Oily substance secreted by sebaceous glands
Flat, scale-like cells composing the epidermis
Arranged in layers
Stratum (plural: strata)
A layer of cells
Outermost layer of the epidermis, which consists of flattened, keratinized (horny) cells
Innermost layer of the skin, containing fat tissue
Fat (see lip/o and steat/o)
Skin (see derm/o)
Ex: Epidermis Dermatitis
Profuse sweating (see hidr/o)
Hard, horny tissue
Fungus (fungi includes yeasts, molds, and mushrroms)
Hair (see trich/o), hair follicle
Sebum (oily secretion from sebaceous glands)
Ex: Squamous epithelium
A lesion is an area of damaged tissue anywhere on or in the body.
It may be caused by disease or trauma.
Collection of dried serum and cellular debris.
A scab is a crust. It forms from the drying of a body exudate, as in seborrhea.
Thick-walled closed sac or pouch containing fluid or semisolid material.
Wearing away or loss of epidermis
Groove or crack-like sore
Discolored (oftened reddened) flat lesion
Solid, round or oval elevated lesion more than 1 cm in diamter
Small (less than 1 cm in diameter), solid elevation of the skin
Benign growth extending from the surface of mucous membrane
Small elevation of the skin containing pus
Open sore on the skin or mucous membranes within the body.
Decubitus ulcers (bedsores) are caused by pressure that results from lying in one position (Latin decubitus means lying down).
Small collection of clear fluid (serum); blister
Smooth, slightly elevated, edematous (swollen) area that is redder or paler than
the surrounding skin
Absence of hair from areas where it normal grows
Ecchymosis (plural: ecchymoses)
Bluish-black mark (bruise) on the skin Ecchymoses (ec-means out, chym/o means to pour) are caused by hemorrhages into the skin from injury or spontaneous leaking of blood from vessels
Petechia (plural: petechiae)
Small, pinpoint hemorrhage
Smaller versions of ecchymoses.
Both ecchymoses and petechiae are forms of purpura (bleeding into the skin).
It arises as the result of stimulation of nerves in the skin by substances released in allergic reactions or by irritation caused by substances in the blood or by foreign bodies.
Be careful to spell pruritus correctly. It is a condition, not an inflammation (-itis)
Acute allergic reaction in which, red, round wheals develop on the skin
Diffuse, acute infection of the skin marked by local heat, redness, pain and swelling
Death of tissue associated with loss of blood supply
Systemic lupus erythematosus (SLE)
Chronic autoimmune inflammatory disease of collagen in the skin, of joints and of internal organs.
Increased growth of cells in the keratin layer of the epidermis caused by pressure or friction
Hypertrophied, thickened scar that occurs after trauma or surgical incision
Thickened and reddened area of the epidermis, usually associated with again or skin damage.
hypertrophy of the stratum corneum
Nasodigital hyperkeratosis is an ailment affecting either the nose or foot pads (or both) of older dogs.
In hyperkeratosis, keratin - the tough, fibrous outer covering of foot pads - grows excessively. Often, the hard, cracked pads appear to have "keratin feathers" around their edges.
Basal cell carcinoma
Malignant tumor of the basal cell layer of the epidermis
Squamous cell carcinoma
Malignant tumor of the squamous epithelial cells of the epidermis.
This tumor may grow in places other than the skin, wherever squamous epithelium is found (mouth, larynx, bladder, esophagus, lungs).
SCC accounts for approximately 15% of cutaneous tumors in the cat and 5% of those in the dog.
SCCs are usually found in unpigmented or lightly pigmented skin.
Cancerous growth composed of melanocytes.
It commonly occurs in dogs with pigmented skin.
Melanomas can occur in what areas?
areas of haired skin (usually benign), where they usually form small, dark (brown to black) lumps, but can also appear as large flat wrinkled masses.
They can also occur in the mouth, toes or behind the eye (these tend to be malignant)