Integumentary System Flashcards
Integumentary system
made up of the skin and its relayed structures, performs important functions in maintaining the health of the body
integument comes from Latin word - to cover or enclose
Functions of the skin
-the skin waterproofs the body and prevents fluid loss
-intact skin plays an important role in the immune system by blocking the entrance of pathogens into the body
-skin is the major receptor for the sense of touch
-skin helps the body synthesize vitamin D, while screening out some harmful ultraviolet radiation
Sebaceous glands
secrete sebum that lubricates the skin and discourages the growth of bacteria on the skin
sweat glands
-helps regulate body temp and water content by secreting sweat
-a small amount of metabolic waste is also excreted through the sweat glands
hair
helps control the loss of body heat
nails
protect the dorsal surface of the last bone of each toe and finger
epidermis
outermost layer of the skin made of several epithelial tissues
epithelial tissues
form a protective covering for all of the internal and external surfaces of the body
squamous epithelial tissue
forms the upper layer of the epidermis, scalelike, this layer consists of flat, scaly cells that are continuously shed
basal layer
lowest layer of the epidermis, new cells are produced then pushed upward, when the cells reach the surface, they die and become filled with keratin
keratin
fibrous, water-repellent protein
melanocytes
special cells that are also found in the basal cell layer, they contain a dark brown to black pigment known as melanin
melanin
pigment that determines the colour of the skin, which depends on the type and amount of this pigment that is present
the dermis
the thick layer of living tissue directly below the epidermis, it contains connective tissues, blood and lymph vessels, and nerve fibers
collagen
tough, yet flexible, fibrous protein material found in the skin, and also in the bones, cartilage, tendons and ligaments
mast cells
found in the connective tissue of the dermis, respond to injury, infection, or allergy by producing and releasing substances, including heparin and histamine
heparin
released in response to an injury and is an anticoagulant
histamine
released in response to allergens, causes the signs of an allergic response
subcutaneous layer
the layer located just below the layers of the skin and connects the skin to the surface muscles, consists of loose connective tissue and adipose tissue
lipocytes
aka fat cells, are predominant in the subcutaneous layer where they manufacture and store large quantities of fat
sebaceous glands
located in the dermis layer of the skin and are closely associated with hair follicles
sweat glands
tiny coiled glands found on almost all body surfaces
hair fibres
rod-like structures composed of tightly fused, dead protein cells filled with hard keratin
-the darkness and colour of the hair is determined by the amount and type of melanin produced by the melanocytes that surround the core of the hair shaft
hair follicles
sacs that hold the root of the hair fibres
-shape of the follicles determines whether the hair is straight or curly
arrector pili
tiny muscle fibres attached to the hair follicles that cause the hair to stand erect
unguis
a fingernail or toenail, the keratin plate that protects the dorsal surface of the last bone of each finger and toe
nail body
translucent, and closely molded to the surface of the underlying tissues
-made up of hard, keratinized plates of epidermal cells
nail bed
joins the nail body to the underlying connectice tissue, nourishes the nail
-blood vessels here give the nail its pink colour
free bed
portion of the nail not attached to the nail bed, extends beyond the tip of the finger or toe
lunula
pale half-moon shaped region at every nail root, this is the active area of the nail where new keratin cells form
cuticle
narrow band of epidermis atatched to the surface of the nail just in front of the root, protecting the new keratin cells as they form
nail root
fastens the nail to the finger or toes by fitting into a groove in the skin
Acne vulgaris
(acne) is a chronic inflammatory disease characterized by pustular eruptions of the skin caused by an overproduction of sebum around the hair shaft
comedo
a non-infected lesion formed by the buildup of sebum and keratin in a hair follicle often associated with acne vulgaris
closed comedo
(whitehead) a comedo with an obstructed opening
sebum plug
a sebum plug that is exposed to air, oxidizes and becomes an open comedo (blackhead)
sebaceous cyst
closed sac associated with a sebaceous gland that is found just under the skin
-these cysts contain yellow, fatty material and are usually found on the face, neck or trunk
seborrhea
overactivity of the sebaceous glands that result in the production of an excessive amount of sebum
sebhorrheic dermatitis
an inflammation sometimes resulting from sebhorrea that causes scaling and itching of the upper layers of the skin or scalp
sebhorrheic keratosis
benign skin growth that has a waxy look
-these growths, which can vary in colour from light to black, occur most commonly in the elderly
anhidrosis
the abnormal condition of lacking sweat in response to heat