Integumentary System Test Flashcards
Of what are the organs of the integumentary system made?
cutaneous membranes
Give the name and location of the four different kinds of membranes.
- Serous membranes: line body cavities that don’t open to the outside; secrete serous fluid
- Mucous membranes: line cavities and tubes opening to the outside; secrete mucus
- Synovial membranes: line joint cavities; secrete synovial fluid
- Cutaneous membranes: cover the body as skin
What is the largest organ by weight?
the skin
Name the major functions of the integumentary system.
- Protects the body from invading microorganisms (unless the skin is broken)
- Prevents water loss from the body
- Helps to regulate body temperature
- Important in the synthesis of vitamin D
- Has sensory receptors for touch, pain, pressure, and temperature
- Excretes small quantities of wastes
The integumentary system is composed of two distinct tissue layers. Name and describe them.
- Epidermis: the outermost layer of the skin; composed of stratified squamous epithelial tissue; avascular (has no blood vessels)
- Dermis: the innermost layer of the skin; composed of connective tissue (collagen, elastin, adipose, blood) smooth muscle tissue, and nervous tissue
How does the function of the epidermis differ from that of the dermis?
The epidermis protects the body, and the dermis nourishes the epidermis with its blood vessels.
What are the accessory structures of the integumentary system or skin?
- hair follicles
- nails
- sweat glands (eccrine and apocrine)
- sebaceous glands
Where is the subcutaneous layer found? Is it a part of the skin?
The subcutaneous layer is located below the dermis. Another name for it is hypodermis. The subcutaneous layer is not considered to be a part of the skin
What is the function of the subcutaneous layer?
- Insulates the body since it is composed of adipose tissue (fat)
- Adheres the dermis to the muscular layer
What are characteristics of the epidermis?
- Composed of stratified squamous epithelium
- Has no blood vessels (is avascular)
- Its outer layers become keratinized (hardened) and “slough” or fall off
- Its innermost layer of cells rests on a basement membrane
- It is thickest on the palms of the hands and soles of the feet
What are the layers (strata) of the epidermis, from the outside to the inside?
- Stratum corneum–outermost, keratinized part of the epidermis
- Stratum lucidum–appears as a clear layer on the palms and the soles
- Stratum granulosum–cells underneath the stratum lucidum
- Stratum spinosa–cells located within dermal papillae
- Stratum basale–layer of cells attached to the basement membrane; contains melanin-containing cells called melanocytes
Why is the boundary between the epidermis and the dermis uneven?
The epidermis has ridges. The dermis has dermal papillae which extend up into the spaces between epidermal ridges, carrying blood vessels to nourish the epidermis. This unevenness leads to unique fingerprints for individuals.
What are the characteristics of the dermis?
- Contains the accessory structures of the skin: hair follicles, nail, sweat glands, and sebaceous glands
- Has blood vessels
- Binds the epidermis to underlying tissue (the subcutaneous layer)
- Has fibrous connective tissue (collagen and elastin) which provide resilience and elasticity
- Has smooth muscle fibers attached to hair follicles; when they contract they cause your hair to stand on end
- Has nerve fibers
- Has sensory receptors like Meissner’s corpuscles and Pacinian corpuscles
Can severely burned or injured dermis tissue always regenerate?
No. If accessory structures (hair follicles, nails sebaceous glands, sweat glands) do not survive, then dermis cannot regenerate. If accessory structures survive, the dermis can regenerate
What is the meaning of these terms associated with hair: hair follicle, hair root, hair shaft, hair papillae, and arrector pili muscle?
- Hair root–portion of the hair from the scalp down
- Hair follicle–tube-like depression of epidermal cells extending down into the dermis; completely surrounds the root of the hair and the hair papillae
- Hair shaft–portion of the hair from the scalp up
- Hair papillae–projection of connective tissue extending up into the hair follicle; enable blood vessels to get to rapidly growing cells in the hair root and nourish them
- Arrector pili muscle–smooth muscle associated with the hair follicle; when it contracts it causes “goose bumps” and hair to stand on end
What are nails?
Protective coverings on the ends of fingers and toes
Differentiate among nail plate, nail bed, and lunula.
- Nail bed–produced from epidermal cells; is continuous with the skin
- Nail plate–portion lying over the nail bed
- Lunula–most actively growing portion of the nail; shaped like a half moon; located at the base of the nail plate; when it grows, it pushes the nail plate over the nail bed
What are some characteristics of sebaceous glands?
- Coiled glandular tissues made up of epidermal cells specialized to form secretions
- Sebum is the name for the secretions of sebaceous glands
- Sebum is composed of oily secretions plus the cells that secreted them
- Sebum acts to keep hair and skin soft, pliable, and waterproof
- Sebaceous glands are always associated with hair follicles
- Sebaceous glands are absent on the palms and the soles
Sebaceous glands are holocrine glands. What does this mean?
They secrete both their secretions plus the cell that secreted them. This means that sebum contains both the cell secretions (oil) and the cells themselves.
What are the two types of sweat glands? How do they compare?
- Eccrine sweat glands
- Consist of a tiny tube originating as a ball-shaped coil lined with sweat-secreting epithelial cells
- Are not associated with hair follicles
- Release sweat to the outside of the body through a pore
- When body temperature increases, eccrine sweat glands respond by secreting sweat
- Sweat functions to cool the body and to rid it of some wastes
- Apocrine sweat glands
- Consist of a tiny tube originating as a ball-shaped coil lined with sweat-secreting epithelial cells
- Are associated with hair follicles
- Sweat is released to outside of body through the hair follicle
- When you are emotionally upset or sexually aroused, apocrine sweat glands respond by secreting sweat
- This sweat develops a scent as it is metabolized by bacteria on the skin
- Apocrine sweat glands become active at puberty and are most numerous in the inguinal (groin) area
Name and describe some common disorders of the integumentary system.
- Acute sunburn–occurs when too much ultraviolet (UV) radiation reaches the skin and causes an inflammation or reddening due to dilation of peripheral blood vessels
- Skin cancer–begins when ultraviolet radiation mutates the DNA of a skin cell
- Contact dermatitis–superficial skin inflammation or irritation resulting from either an immune response or exposure to an irritant
- Acne–inflammation of sebaceous gland caused by hormones signaling an increased release of sebum
What is melanin? What is its function?
- Melanin is a pigment produced by melanocytes (pigment cells) located in the stratum basale of the epidermis
- Melanin helps to protect the skin excess UV radiation
- Melanin production increases upon exposure to the sun and darkens the skin
Why do some individuals have darker skin than others?
People with dark skin have (1) more melanin pigment and (2) larger pigment granules
How does the body react to acute sunburn?
- Melanocytes in the stratum basale produce more melanin pigment
- The stratum corneum sheds cells which might be damaged by UV radiation
