Chapter 6 - Skin and membranes Flashcards
epithelial membrane
membranes composed of epithelial tissue and an underlying layer of fibrous connective tissue
connective tissue membrane
membranes composed exclusively of various types of connective tissue. No epithelial cells are present in this type of membrane
cutaneous membrane
another name for the body’s skin, made up of the dermis and epidermis
serous membrane
membranes lining closed internal body cavities, made up of two layers called the parietal and visceral layers
parietal layer
the serous membrane that lines the walls of a body cavity much like wallpaper covers the walls of a room
visceral layer
the portion of the serous membrane that folds inward to cover the surface of organs within a body cavity
pleura
the serous membrane around each lung
peritoneum
in the abdominal cavity, the serous membrane covering most of theorgans
pericardium
the serous membrane around the heart
pericardial fluid
a lubricating fluid between the parietal and visceral layers of the pericardium
pleurisy
a very painful pathological condition characterized by inflammation of the serous membranes (pleura) that line the chest cavity and cover the lungs. Pain is caused by irritation and friction in the inflamed pleura as the lung rubs against the wall of the chest cavity. In severe cases, the inflamed surfaces of the pleura fuse together and permanent damage may develop.
peritonitis
inflammation of the serous membranes in the abdominal cavity. Peritonitis can be a serious complication of an infected appendix.
mucous membranes
epithelial membranes that contain both an epithelial layer and a fibrous connective tissue layer. These membranes line body surfaces opening directly to the exterior of the body. Examples of mucous membranes include those lining the respiratory, digestive, urinary, and reproductive tracts. The epithelial component of a mucous membrane varies, depending on its location and function. In most cases, the cell composition is either stratified squamous or simple columnar epithelia
mucus
a thick, slimy material produced by the epithelial cells of most mucous membranes; it keeps the mucous membranes moist and soft
lamina propria
the fibrous connective tissue underlying the epithelium in mucous membranes
mucocutaneous junction
the transitional area that serves as a point of “fusion” where skin and mucous membranes meet. Such junctions lack accessory organs such as hair or sweat glands that characterize skin. These transitional areas are generally moistened by mucous glands within the body orifices or openings where these junctions are located. The eyelids, lips, nasal openings, vulva, and anus have mucocutaneous junctions that may become sites of infection or irritation.
bursae
fluid-filled sacs between tendons and bones that function as cushions
synovial membrane
a connective tissue membrane lining the spaces between bones and joints that secretes synovial fluid
epidermis
the outermost layer of the skin. It is a relatively thin sheet of stratified squamous epithelium.
dermis
the deeper of the two layers. It is thicker than the epidermis and is made up largely of connective tissue.
hypodermis
also called subcutaneous tissue or superficial fascia; it is a thick layer of loose connective tissue and fat that lies below the dermis and connects it to the muscles and bones. Fat in the subcutaneous layer insulates the body from extremes of heat and cold. It also serves as a stored source of energy for the body and can be used as a food source if required. In addition, the subcutaneous tissue acts as a shock-absorbing pad and helps protect underlying tissues from injury caused by bumps and blows to the body surface.
stratum germinativum
the basal layer of the epidermis consisting of a single row of columnar or cuboidal epithelial cells that continually divide and replace the rest of the epidermis as it wears away
basal layer (epidermis)
the innermost layer of the epidermis; it contains small round cells called basal cells
keratin
a tough, waterproof material that provides cells in the outer layer of the skin with a horny, abrasion-resistant, and protective quality; it is a fibrous protein forming the main structural constituent of hair, feathers, hoofs, claws, horns, etc.
basal cell
a type of cell in the innermost layer of the epidermis or other epithelial tissue
stratum corneum
the outermost layer of the epidermis
melanin
a brown pigment produced by cells in the basal layer called melanocytes; the more melanin in the skin, the darker the skin color; melanin protects against UV radiation
melanocytes
a mature melanin-forming cell, especially in the skin
cyanosis
a bluish discoloration of the skin resulting from poor circulation or inadequate oxygenation of the blood
basement membrane
also called a basal lamina; a sheet of proteins and other substances to which epithelial cells adhere and that forms a barrier between tissues
dermal-epidermal junction (DEJ)
the area of tissue that joins the epidermal and the dermal layers of the skin
dermal papillae
small, nipple-like extensions of the dermis into the epidermis; they play an important role in stabilizing the dermal-epidermal junction
blister
a baglike fluid-filled elevation of the skin caused by an irritant such as heat, friction, or a chemical
papillary layer
the upper region of the dermis where the dermal papillae reside
reticular layer
The deeper area of the dermis, filled with a dense network of interlacing fibers. Most of the fibers in this area are collagen that gives toughness to the skin. However, elastic fibers are also present. These make the skin stretchable and elastic (able to rebound). As we age, the number of elastic fibers in the dermis decreases, and the amount of fat stored in the subcutaneous tissue is reduced. Wrinkles develop as the skin loses elasticity. The skin sags and becomes less soft and pliant.
friction ridges
skin that is present along the lengths of the fingers, across the palmar surfaces of the hand, and on the soles of the feet. The skin contains raised ridges and recessed furrows that are used for gripping and other mechanical motions. (used in fingerprinting and other things)
liposuction
a surgical procedure that involves inserting a hollow tube into the subcutaneous tissue and removing fat with a vacuum aspirator
aspiration
(1) a strong desire to achieve something high or great; (2) a drawing of something in, out, up, or through by or as if by suction
hypodermic needles
needles used to inject materials into the hypodermis
follicle
a small secretory cavity, sac, or gland
lanugo
fine, soft hair, especially that which covers the body and limbs of a human fetus or newborn
hair follicle
the sheath of cells and connective tissue which surrounds the root of a hair
shaft
the visible part of a human hair
hair papilla
a small bump at the base of the hair follicle that produces the hair
arrector pili muscle
a muscle, attached to the hair follicle, that involuntarily contracts when frightened or cold; it makes the hair stand up straight
goose bumps
the bumps on a person’s skin at the base of body hairs which may involuntarily develop when a person is tickled, cold or experiencing strong emotions such as fear, euphoria or sexual arousal; it is created by a contraction of the arrector pili muscle
nail body
the visible part of the nail
free edge
the part of the nail body that is farthest from the root; it extends out from the finger and is the part that needs to be clipped
lunula
the part of the nail body nearest the root, often seen as a crescent-shaped white area
cuticle
a fold of skin that covers the nail root
nail root
the part of the nail that is hidden by the cuticle
nail bed
a layer of epithelium under the nail body; it contains blood vessels; if blood oxygen levels drop and cyanosis develops, the nail bed will turn blue
lamellar corpuscle
also called Pacini corpuscle; a skin receptor which detects pressure and vibration deep in the dermis
tactile corpuscle
also called Meissner corpuscle; a skin receptor which detects light touch
corpuscle
a minute body or cell in an organism, especially a red or white cell in the blood of vertebrates
sudoriferous glands
another name for sweat glands; there are two types: eccrine and apocrine
eccrine sweat gland
by far the more numerous, important, and widespread sweat glands in the body. They are quite small and, with few exceptions, are distributed over the total body surface. Throughout life they produce a transparent, watery liquid called perspiration, or sweat
apocrine sweat gland
sweat glands found primarily in the skin in the axilla (armpit) and in the pigmented skin areas around the genitals; they produce a thicker version of sweat than eccrine sweat glands. The odor associated with apocrine gland secretion is not caused by the secretion itself. Instead, it is caused by the contamination and decomposition of the secretion by skin bacteria. Apocrine glands enlarge and begin to function at puberty.
sweat
a secreted liquid that assists in the elimination of waste products such as ammonia and uric acid and also works to help cool the body down
pore
small holes in the skin that come from outlets of small ducts from the eccrine sweat glands
duct
a bodily tube or vessel especially when carrying the secretion of a gland
sebaceous glands
glands that secrete oil for the hair and skin; their tiny ducts open into hair follicles so that their secretion, called sebum, lubricates the hair and skin
sebum
an oily secretion of the sebaceous glands
comedo (plural: comedones)
a clogged hair follicle (pore) in the skin; A comedo can be open (blackhead) or closed by skin (whitehead) and occur with or without acne.
five functions of skin
(1) protection; (2) temperature regulation; (3) sensation; (4) excretion; (5) synthesis of vitamin D
repair of skin process
(1) clotting of blood stops blood loss
(2) cells of stratum germinativum produce more epithelial cells to rebuild the epidermis as the clot dissolves
(3) fiber-producing cells of the dermis replace torn collagen fibers, sometimes producing extra-dense scar tissue
blushing
a reddening of the skin caused by an increase in the local blood supply, often with a psychological cause and usually restricted to the face, cheeks or ears
flushing
a reddening of the skin caused by an increase in the local blood supply, often with a physiological cause; it can spread to multiple parts of the body and is sometimes associated with carcinoid syndrome
carcinoid syndrome
a combination of symptoms caused by the release of serotonin and other substances from carcinoid tumors of the gastrointestinal tract
carcinoid
a tumor of a type occurring in the glands of the intestine (especially the appendix) or in the bronchi, and abnormally secreting hormones
bronchi
(singular: bronchus) any of the major air passages of the lungs which diverge from the windpipe
trachea
also called the windpipe; the air passage from the throat to the lungs
synthesis of vitamin D
when the skin is exposed to UV light, usually from the sun, a precursor substance in skin cells is transported to the liver and kidneys where it is converted into an active form of vitamin D
squamous cell carcinoma
malignant tumor of the epidermis; slow-growing cancer that is capable of metastasizing; the most common type of skin cancer
basal cell carcinoma
one of the most common forms of skin cancer, usually occurring on upper face, with low potential for metastasizing
malignant melanoma
a type of skin cancer that develops from the pigment-producing cells known as melanocytes
metastasizing
(of a cancer) spread to other sites in the body by metastasis
metastasis
the development of secondary malignant growths at a distance from a primary site of cancer
five warning signs of malignant melanoma
(1) asymmetrical appearance
(2) irregular or indistinct borders
(3) unevenly colored
(4) larger than 1/4 inch
(5) evolves in size or shape over time and begins to itch or hurt
three factors that determine seriousness of burns
(1) Depth and number of tissue layers involved
(2) Total body surface area affected
(3) Type of homeostatic mechanisms such as respiratory or blood pressure control and fluid and electrolyte balance that are damaged or destroyed
rule of nines
a method doctors and emergency medical providers use to easily calculate the treatment needs for a person who’s been burned; it divides the body up into arms, legs, trunk, head, and genitals, for a total of 11 areas of 9% body surface and 1 area of 1% body surface (genitals)
first-degree burn
A superficial burn that causes minor discomfort and some reddening of the skin. Although the surface layers of the epidermis may peel in 1 to 3 days, no blistering occurs, and actual tissue destruction is minimal
second-degree burn
A burn that involves the deep epidermal layers and always causes injury to the upper layers of the dermis. Although deep second-degree burns damage sweat glands, hair follicles, and sebaceous glands, complete destruction of the dermis does not occur. Blisters, severe pain, generalized swelling, and fluid loss characterize this type of burn. Scarring is common.
third-degree burn
a burn characterized by complete destruction of the epidermis and dermis. In addition, tissue death extends below the primary skin layers into the subcutaneous tissue. Third-degree burns often involve underlying muscles and even bone.
partial-thickness burns
another name for first and second degree burns
fourth-degree burn
a burn that extends below the subcutaneous tissue to reach muscle or bone. Such injuries may occur as a result of high-voltage electrical burns or from exposure to very intense heat over time. Treatment may require extensive skin grafting and even amputation of limbs.
full-thickness burn
another name for third and fourth degree burns
