Chapter 10 Flashcards
What is included in the integumentary system?
- skin
- appendages: hair, nails, and skin glands
What type of membrane is skin?
-cutaneous membrane
What are the two layers of the skin?
- epidermis
- dermis
What are the cells that make up the epidermis?
- keratinocytes
- melanocytes
- dendritic (Langerhans) cells
- tactile (Merkel) cells
What are the functions of the cells of the epidermis?
- keratinocytes: produce keratin, 90% of cells
- melanocytes: make colored pigment, decreases UV light penetration
- dendritic (Langerhans) cells: find bacteria and phagocytose them; immune response
- tactile (Merkel) cells: serve as light touch receptors
What are the 5 layers of the epidermis?
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- Stratum Basale
- Stratum Spinosum
- Stratum Granulosm
- Stratum Lucidum
- Stratum Corneum
Describe the Stratum Basale.
- base layer
- single layer of columnar cells
- growth layer: only one to undergo mitosis
Describe the Stratum Spinosum.
- spiny layer
- irregularly shaped cells with bridges (desmosomes)
Describe the Stratum Granulosm.
- granular layer
- where keratin starts to form in the cells
- 2-4 cell layers thick
Describe the Stratum Lucidum.
- clear layer
- keratinocytes are very flat and closely packed
Describe the Stratum Corneum.
- horny layer
- most superficial
- thin, squamous cells
- barrier area of the skin
Which layers aren’t always present and why?
- Stratum Lucidum: only found in thick skin, reduces friction
- Stratum Granulosum
How does the epidermis grow and repair? How long does it take?
- mitosis occurs in the stratum basale and the replacement keratinocytes push up through each layer
- 35 day “turnover time” unless an abrasion occurs
What is the dermoepidermal junction?
- the area between the dermis and the epidermis
- the partial barrier to the passage of the cells and large molecules
What structures do you find in the dermis?
- muscle fibers
- hair follicles
- sweat glands
- sebaceous glands
- lymphatic vessels
- blood vessels
What are the two layers in the dermis?
- Papillary Layer
- Reticular Layer
Describe the reticular layer and what type of tissue is found there?
- thick layer
- dense irregular connective tissue (collagen and elastic fibers)
- contains hair follicles and glands and thousands of sensory receptors
Describe the papillary layer and what type of tissue is found there?
- thin layer
- contains loose fibrous connective tissue (collagenous and elastic fibers)
- dermal papillae are the bumps in the superficial layer of the dermis
What structures are anchored to the reticular layer?
- skeletal muscle: in face and scalp
- smooth muscle: surrounding hair follicles (arrector pili)
How does the dermis grow and repair?
- rapid regeneration of the connective tissue in the dermis
- cutting parallel to the cleavage (collagenous) lines will leave a less noticeable scar
- overstretching of elastic fibers cause them to weaken and tear causing stretch marks
What is the hypodermis?
-connection between skin and underlying body structures
Is the hypodermis part of the integument?
-subcutaneous layer (not the skin)
What type of tissue is found in the hypodermis?
-mostly loose fibrous connective tissue and adipose tissue
What are other structures found in the hypodermis?
-some nerves, blood vessels, and lymphatic vessels
How is the hypodermis clinically important?
-great site for rapid and pain-free absorption and injections
What is melanin?
-the pigment that controls skin color
What produces melanin?
-melanocytes
What are the two types of melanin?
- Eumelanin: true black color
- Pheomelanin: dusky black color
How can skin color change temporarily?
- sunlight ex. sunburn or tan
- hemoglobin ex. red color
- flushed or pale controlled by dilation or constriction
- cyanotic ex. blue color because of lack of oxygen in blood
What is bruising?
- damage to blood vessels in the skin
- red blood cells are released: turn from bright red to maroon (hemoglobin)
- as the hemoglobin is broken down it turns brown, green, or yellow
What are the functions of the skin?
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- Homeostasis
- Protection
- Sensation
- Growth
- Excretion
- Synthesis of important chemicals and hormones
- Temperature regulation
- Immunity
- Absorption of important substances
How does the skin provide homeostasis? Example
-produces hormones: any chemical substance produced in one body area and is transported to another location by blood
How does the skin provide protection? Example
- keratinized stratified squamous epithelium acts as a barrier
- melanin protects from UV light
- protects against dehydration
- secretes a surface film to act against toxins
How does the skin provide sensation? Example
- contains millions of somatic sensory receptors
- detect pressure, touch, temp, pain, and vibration
- allows our body to respond to changes
How does the skin provide growth? Example
- the skin grows as we grow
- can stretch and recoil to prevent tearing
How does the skin provide excretion? Example
- the skin contains glands that secrete substances
- sweat(apocrine and eccrine) and sebaceous
How does the skin provide synthesis of important chemicals and hormones? Example
-produces vitamin D which will influence other important chemical reactions
How does the skin provide immunity? Example
-dendrites: recognize pathogenic organisms to trigger the immune response
How does the skin provide absorption of important substances? Example
-through the hair and pass through the layers and into the blood
How does the skin maintain heat homeostasis?
- Vasoconstriction
- Vasodilation
What are four ways that we can lose heat from the epidermis? Describe
-heat is lost by evaporation (sweat), radiation (transfers without contact), conduction (transfers with contact), or convection (something carries the heat away)
What are the integument appendages?
- hair
- nails
- glands
What are the functions of the hair?
- protection
- reduction of heat loss
- sensing light touch
What is the structure of the hair?
- shaft: above the skin
- root: penetrates into the dermis
- epithelial root sheath
- dermal root sheath
What is a sebaceous gland?
-a gland that produces an oily substance into each hair follicle
What are nails?
-heavily keratinized epidermal cells
What is the structure of a nail?
- nail body (visible part)
- nail root (under the skin)
- nail bed (right under nail body); contains blood vessels
What is the clinical significance of the nails blood supply?
-cyanosis occurs here first
What are the three different types of glands?
- sweat glands
- sebaceous glands
- ceruminous glands
Describe the sweat glands.
- eccrine: cool body by evaporation and eliminates small amounts of wastes
- apocrine: in axillary and genital regions and secreted during emotional stress or excitement
Describe sebaceous glands.
- secrete oil for the hair and skin
- antifungal effect
- cause whiteheads and blackheads with oxidation
Describe ceruminous glands.
- modified sweat glands
- in ear canal
- produce cerumen, ear wax
- prevents entry of foreign bodies
How does the integument change with age?
- wrinkles
- dehydration
- thin skin
- less sweat
- hair and nail production worsens
What does the dermoepidermal junction have and what does it do?
- Basement membrane
- includes special fibrous elements that cement the superficial epidermis to the dermis
What does the dermis help do?
-it helps regulate body temperature
What type of sensory information does the dermis detect?
- pain
- pressure
- touch
- temperature
What does the surface film do?
- antibacterial activity
- lubrication
- hydration
- blockade of many toxic agents
