Science Olympiad- Integumentary System

Integumentary organ system

A body system comprised of the cutaneous membrane (skin), hair, nails, associated glands, and the subcutaneous tissue. It functions include: protection against injury and infection, thermoregulation, sensory perception, regulation of water loss, and chemical synthesis.

Serous membrane

A type of membrane that lines the body cavities that lack openings to the outside. they form the inner linings of the thorax and abdomen, and they cover organs within these cavities. This membrane consists of a squamous epithelium and a thin layer of loose connective tissue and secretes serous fluid, which lubricates the surfaces of the membrane.

Squamous

Relating to, consisting of, or denoting a layer of epithelium that consists of very thin flattened cells.

Mucous membrane

A type of membrane that lines the cavities and tubes that open to the outside of the body, including the oral and nasal cavities, and the tubes of the digestive, respiratory, urinary, and reproductive systems. This membrane secretes mucus and consists of epithelium overlying a layer of loose connective tissue, but the type of epithelium differs with location of the membrane.

Synovial membrane

A type of membrane that forms the inner linings of the joint cavities between the ends of bones at freely movable joints (synovial joints). These membranes include fibrous connective tissue, overlying loose connective tissue and adipose tissue. This type of membrane secretes synovial fluid, a thick, colorless fluid, which lubricates the joints.

Cutaneous membrane

An organ in the integumentary organ system more commonly known as the skin.

Epidermis

The outer layer of skin that is composed of stratified squamous epithelium and lacks blood vessels. This outer layer is made up of 5 sublayers, including the stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale. Also, this layer is separated from the dermis by a basement membrane.

Dermis

The inner layer of skin that is thicker than the epidermis and contains fibrous connective tissue (collagen and elastin), epithelial tissue, smooth muscle tissue, nervous tissue, hair follicles, sebaceous glands, sweat glands, and blood vessels. It is separated from the epidermis by a basement membrane, which is anchored to this inner layer by short fibrils.

Epidermolysis bullosa (EB)

An inherited condition that destroys the vital integrity of the skin's layered organization. Symptoms include easy blistering and scarring.

Subcutaneous layer

Also called the hypodermis, this is a layer of tissues beneath the dermis that is comprised primarily of loose connective tissue and adipose tissue that bind the skin to underlying organs. This serves as a mechanism of insulation as well. Infants and elderly have less of this than adults and thus are more susceptible to cold.

Psoriasis

A chronic, non-infectious skin disease in which cells in the epidermis divide 3 to 4 times more frequently than normal. This results in the accumulation of excess cells, forming a thick stratum corneum with bright red patches covered with silvery scales, which are keratinized cells. There appears to be a genetic component, but it is triggered by trauma, infection, hormonal changes, or stress. Can be treated by an anti-cancer drug.

Keratinocytes

Older cells, that produce keratin and whose cell membranes have thickened and developed desmosomes that fasten them to adjacent cells. These make up 90% of epidermal cells.

Stratum corneum

Also known as the horny layer, this is the outermost layer of the epidermis that is made up of 25 to 30 layers of tough, tightly packed, fully keratinized, and non-nucleated dead cells. This layer constantly sheds and is constantly replaced by cells from deeper strata.

Stratum lucidum

A layer between the stratum corneum and stratum granulosum that is found only on the soles and palms (thick skin). It is made up of 3 to 5 layers of clear, dead, flat keratinocytes with densely packed intermediate filaments and thick plasma membranes.

Stratum granulosum

A layer of the epidermis found beneath the stratum corneum (if stratum lucidum is not present), and is 3-5 layers of keratinocytes undergoing apoptosis. This stratum contains keratohyalin and lamellar granules, which secrete a lipid-rich secretion that acts as a water sealant.

Stratum spinosum

A layer of the epidermis found under the stratum granulosum. This layer consists of 8 to 10 layers of cells with centrally located, large, oval, nuclei, that are developing fibers of keratin. Cells are starting to flatten. As the name suggests, these cells have spinelike projections as a result of filaments from the cytoskeleton (these spiny things join cells together).

Stratum basale

The deepest layer of the epidermis, made up of a single layer of cuboidal or columnar keratinocytes that undergo mitosis and grow. This layer includes melanocytes. The rate at which these cells divide increases with injury.

Calluses

Thickened areas of the skin that occur when the skin is rubbed or pressed regularly.

Corns

Horny, conical masses on the toes when poorly fitting shoes rub the skin.

Melanocytes

Cells of the stratum basale, that synthesize the dark pigment melanin, which absorbs light energy and in this way protects the cells of other organs from being damaged by ultraviolet rays. Melanin can then be passed from these cells to contiguous cells via cytocrine secretion. These make up about 8% of epidermal cells. The number of these cells is approximately the same for all races.

Papillae

Fingerlike oscillations in the basement membrane that pass into the spaces between cutaneous ridges.

Pacinian (Lamellar) corpuscles

A type of dermal sensory receptor that is stimulated by heavy pressure and can sense vibration changes deep in the skin. These receptors are relatively large, ellipsoidal structures that are composed of connective tissue fibers and cells. Can be found at the border between the dermis and the hypodermis. Every square centimeter of skin contains around 14.

Meissner's corpuscles

Located in dermal papillae, this is a sensory receptor that is sensitive to light touch. These receptors are small, oval masses of flattened connective tissue cells in connective tissue sheaths. Located in the skin of: palms, soles, lips, eyelids, external genitals, and nipples.

Thermoreceptors

Temperature receptors, including heat receptors and cold receptors. There are more cold receptors (krause bulbs and cold receptors on free nerve endings) than heat receptors (ruffini's corpuscles and hot receptors on free nerve endings) in the body: about 6 cold ones for every 1 warmth.

Sunburn

An erythema resulting from excessive ultraviolet radiation, which denature collagen an elastin while dilating blood vessels. Cells in the skin undergo apoptosis and peel off, revealing blisters.

First-degree burns

Burns that affect only the outer layer (epidermis) of the skin. They cause pain, redness, and swelling. An example would be a sunburn. Also called a superficial burn.

Second-degree burns

Burns that affect both the outer (epidermis) and underlying layer (dermis) of skin, but to not go into the subcutaneous tissue. They are characterized by the presence of blisters (due to fluid buildup beneath the epidermis) and also cause pain, redness, and swelling. They are also called partial thickness burns.

Third-degree burns

Burns that affect all of the dermis and sometimes even the deep layers beyond the skin, that is, the hypodermis/subcutaneous layer. Results in black or white burned skin and numbness. May also cause: dehydration from fluid loss, electrolyte imbalance, susceptibility to infections, and a slow recovery. Treatment may be autografts or cadaver/pig skin. They are also called full-thickness burns.

Minor burns

A category of burns that includes first degree burns anywhere on the body and second degree burns less than 2-3 inches wide.

Major burns

A category of burns that includes third-degree burns,

second-degree burns more than 2-3 inches wide, and

second-degree burns on the hands, feet, face, groin, buttocks, or a major joint

Xeroderma pigmentosum

An inherited disorder in which a person lack DNA-repair enzymes, and can never venture outside without being fully clothed or covered in sunblock due to ultraviolet light, which will inevitably damage DNA.

Chicken pox (Varicella)

A type of rash in which tiny-pustules start on the back, chest, or scalp and spread for 3 or 4 days. Pustules form blisters, then crusts, then fall away.

Fifth disease

A type of rash that begins with "slapped cheek" appearance, then red spots suddenly cover the entire body, lasting 2 days.

Impetigo

A bacterial rash characterized by thin-walled blisters (pustules) and thick, crusted, yellow lesions. It is caused by the bacterium Streptococcus.

Lyme disease

A large rash resembling a bull's-eye usually on the thighs or trunk.

Rosacea

A rash in which flushing leads to a sunburned appearance n the center of the face. Red pimples and then wavy red lines develop.

Roseola infantum

A rash that, after a high fever, causes red spots to suddenly cover the entire body, lasting up to 2 days.

Scarlet fever

A rash resembling sunburn with goose bumps. This begins below the ears, on the chest, and under the arms and spreads to the abdomen, limbs, and face. Skin may peel.

Shingles

A rash characterized by small, clear blister that appear on inflames skin. The blisters enlarge, become cloudy, crust, and then fall off.

Hair follicle

A tubelike depression that extends form the surface into the dermis in which a hair grows from.

Folliculitis

An inflammation of the hair follicles in response to bacterial infection.

Melanin

A pigment that determines both skin and hair color. Also, this chemical is important for protecting cells against ultraviolet damage. It is synthesized in the stratum basale as well as in the hair matrix.

Albinism

An inherited condition in which the skin and hair is nonpigmented due to a mutant melanin gene, that is, they are unable to make tyrosinase. People with this disease have melanocytes but cannot synthesize melanin,

Trichosiderin

An iron pigment that renders hair red.

Arrector pili muscle

A bundle of smooth muscle cells attached to each hair follicle. Contraction of this muscle produces goose bumps (piloerection--in latin, cutis anserina) by pulling the normally slanted hair straight up.

Nails

Protective coverings on the ends of the fingers and toes that are made of packed, hard, keratinized cells.

Nail plate

A covering produced by specialized epithelial cells that overlies the nail bed.

Nail bed

The surface of the skin beneath the nail plate.

Lunula

The whitish, thickened, half-moon-shaped region at the base of the nail that is the most actively growing region of the nail plate.

Androgenic alopecia

Pattern baldness, which is associated with testosterone, an androgenic hormone.

Alopecia areata

An inherited condition in which the body synthesizes antibodies to attack hair follicles, resulting in oval bald spots in mild cases to complete loss of scalp and body hair in severe cases.

Sebaceous glands

Glands in the dermis that contain groups of specialized epithelial cells and are usually associated with hair follicles. They are absent on the palms an soles. They are holocrine glands, meaning that their cells produce sebum until the explode (lyse) and then are secreted.

Sebum

Made up of fats, cholesterol, proteins, inorganic salts, and pheromones, this mixture is secreted into hair follicles through short ducts and helps to keep the hair and skin pliable and relatively waterproof. Also, this helps retard bacteria growth and prevents excessive evaporation.

Acne

A disorder of the sebaceous glands in which the glands are overactive or inflamed and become plugged, resulting in small red elevations of the skn.

Sweat glands (sudoriferous glands)

Glands that secrete sweat and consist of a tiny tube that originates as a ball-shaped coil in the deeper dermis or superficial subcutaneous layer. There are both eccrine and apocrine glands.

Eccrine glands

Also called merocrine sweat glands, these respond throughout life to body temperature elevated by environmental heat or physical exercise and are common on the forehead, back, and neck. Regulated by the sympathetic nervous system, these glands produce the moisture on the palms and soles when a person is emotionally stressed. They also function in waste removal.

Pore

The small tiny openings in the skin where sweat is secreted by a tube.

Apocrine glands

Certain sweat glands that produce scented fluid that contains both lipids and proteins as well as the normal components of sweat. These glands become active at puberty and can wet certain areas of the skin when a person is emotionally upset, frightened, aroused, or in pain. These are numerous in axillary regions, which include the groin, armpits, and the area around the nipples. These glands are associated with hair follicles and can be specialized to make other specific fluids. For example, the ceruminous glands of the ear canal synthesize ear wax.

Hypothalamus

The part of the brain that contains the body's temperature set point as well as many other homeostatic mechanisms. This part of the brain can signal muscles in the walls of specialized dermal blood vessels to dilate, resulting in more blood escaping to the outside. At the same time, vasoconstriction deeper blood vessels diverts blood to the surface, resulting in erythema.

Radiation

The primary means of body heat loss, in which infrared heat rays escape from warmer surfaces to cooler surroundings.

Conduction

A method of body heat loss in which heat moves form the body directly into molecules of cooler objects in contact with its surface. For example, touching a water bottle filled with ice water makes a persons hand loose heat.

Convection

A method of body heat loss in which heat from a warmer surface is absorbed by air molecules that contact the body.

Evaporation

Another means of body heat loss in which the body temperature rises above normal and the nervous system stimulates eccrine sweat glands to release sweat onto the surface of the skin. As the sweat evaporates, it takes its heat with it.

Cyanosis

The presence of a blue tint to skin. This can be plainly visible if a person stops breathing or if a person albinism has a low blood oxygen concentration (deoxygenated hemoglobin appears darker in both cases).

Jaundice

A condition in newborns characterized by slightly yellowish skin. This condition can be caused by an immature liver (obstructive jaundice) or blood incompatibility (hemolytic jaundice), resulting in a buildup of the yellowish pigment bilirubin, which is normally processed by the liver and deposited into the small intestine for excretion.

Inflammation

A normal response to injury or stress that results in swelling, redness, heat, and pain due to vasodilation and, thus, more blood in a specific area.

Birthmark

Vascular or skin tumor of the skin and subcutaneous tissue, visible at birth or soon after.

Boil

A bacterial infection (furuncle) of a hair follicle and/or sebaceous glands.

Carbuncle

A bacterial infection, similar to a boil, that spreads into the subcutaneous tissues.

Cyst

A liquid-filled sac or capsule.

Eczema

A noncontagious skin rash often accompanied by itching, blistering, and scaling.

Erythema

Reddening of the skin due to dilation of dermal blood vessels in response to: injury, infection, heat exposure, inflammation, allergies, emotional state, or hypertension.

Herpes

An infectious disease of the skin usually caused by the herpes simplex virus and characterized by recurring formations of small clusters of vesicles.

Keloid

An elevated, enlarging fibrous scar usually initiated by an injury.

Mole

Also called a nevus, this is a fleshy skin tumor that is usually pigmented; colors range from brown to black.

Pediculosis

A disease produced by an infestation of lice.

Pruritus

Itching of the skin.

Pustule

An elevated, pus-filled area.

Scabies

A disease resulting form an infestation of mites.

Seborrhea

Hyperactivity of the sebaceous glands, accompanied by greasy skin and dandruff.

Ulcer

An open sore.

Urticaria

An allergic reaction of the skin that produces reddish, elevated patches (hives).

Wart

Also called a veruca. A flesh-colored, raised area caused by a viral infection by HPV.

Vitiligo

An autoimmune condition in which the immune system mistakenly attacks melanocytes, causing the pigment to be lost from areas of the skin. This produces whitish patches (think Michael Jackson's disease).

ABCDE signs

A method of assessing a skin lesion suspected of being a malignant melanoma.

A-asymmetry

B-border

C-color

D-diameter

E-evolution (change)

Tyrosinase

An enzyme arising from the TYR gene that is essential to the melanin synthesis pathway. This enzyme catalyzes the conversion of tyrosine to dopa, an intermediary molecule, and the conversion of dopa to dopaquinone, which can then be processed into melanin. The melanin is then packaged into melanosomes.

Melanosomes

Organelles found in animal cells, and fis the cellular site of synthesis, storage and transport of melanin. These are responsible for color and photoprotection in animal tissues and can move from melanocytes to keratinocytes in the epidermis by exocytosis at the dendrite of a melanocyte.

Eumelanin

One of the two types of melanin. This type is either dark brown or black and actually provides protection against ultraviolet radiation.

Pheomelanin

One of the two types of melanin. This type has a light yellow or red color (due to it containing sulfur) and provides little protection against ultraviolet radiation, breaking down in response to too much ultraviolet exposure. It is found in blonde hair and white skin.

Striae

A linear mark, slight ridge, or groove on the surface of the skin due to overstretching.

Cuticle

The outermost layer of the hair, made of keratin. This is really a series of overlapping scales - very resistant to chemical decomposition

Cortex

The intervening layer of the hair (i.e., between the cuticle and the medulla). It is made of spindle shaped cells and has pigment granules in dark hair but air bubbles (cortical fusi) in gray/white hair. You may also find ovoid bodies (look like large pigment granules) in this area.

Medulla

The innermost layer of the hair. It is made of cells that form a shaft through the middle of the hair. It contains pigment granules and air spaces.

Ceruminous glands

Modified apocrine sweat glands in the ear canal that produce earwax.

Langerhans cells

Dendritic cells (antigen-presenting immune cells) of the skin and mucosa that originate in bone marrow (via hematopoiesis) and contain large granules called Birbeck granules. They are present in all layers of the epidermis, but are most prominent in the stratum spinosum, as they are easily damaged by UV light.

Vitamin D

A fat soluble vitamin that, when in its active form, promotes calcium absorption by the body and increases calcium and phosphate levels in bones. It may be synthesized in response to exposure to ultraviolet radiation (sunlight) or may be absorbed in the small intestine.

Merkel cells

Epidermal cells (least numerous type of cell) found in the basement membrane that are closely associated with oval receptors called merkel discs. These discs have synaptic contacts with somatosensory afferent neurons. They are associated with the sense of light touch and discrimination of shapes and textures. They can turn malignant and form the skin tumor known as Merkel cell carcinoma.

Hair root plexus

A special group of nerve fiber endings and serves as a very sensitive mechanoreceptor for touch sensation. Each one forms a network around a hair follicle and is a receptor, which means it sends and receives nerve impulses to and from the brain when the hair moves.

Anagen

This growth phase of the hair cycle lasts two to six years and determines the length of our hair (virtual maximum=1 meter). As cells form at the root of the hair shaft, older cells are pushed out of the follicle, becoming the hair we see. The reason some hairs on our body grow longer than others is because they have different growth phases. The rate of growth is affected by illness, gender, diet, stress, radiation therapy, and medication.

Catagen

This is the transitional (or regression) stage of the hair cycle that lasts about 1-2 weeks. The hair follicle shrinks (to about 1/6 the normal length) and detaches from the dermal papilla. Also, cells of hair matrix stop dividing.