Chapter 4: Integumentary System Flashcards
What are the two components if the integumentary system?
- ) Cutaneous Membrane
2. ) Accessory Structures
What are the functions of the integumentary system?
- ) protects deeper tissues (see slide for all)
- ) aids in heat regulation
- ) aids in excretion of urea and uric acid
- ) Synthesizes vitamin D
What are 4 epidermis characteristics?
- ) Stratified squamous epithelium
- ) Lacks blood vessels but can divide
- ) As new cells grow, push older ones to surface
- ) Outer most layer is dead
What are the 4 Epidermal cell types?
Keratinocytes
Melanocytes
Langerhan cells
Merkel cells
What do Keratinocytes do? What percent of epidermal cells are keratinocytes?
produce keratin and provide protection
90%
Where do langerhan cells come from? what system are they in?
bone marrow; immune system
what do merkel cells do?
form touch receptors with sensory neuron
_______ cells divide to produce _________ at the __________
stem; keratinocytes; basal lamina
As Keratinocytes are pushed up towards to surface they…… (2 things)
- fill with keratin and oils
- slowly die
How long is a keratinocytes journey?
4 weeks unless outer layers removed by abrasion
What are the five layers of epidermis?
- ) stratum germinativum
- ) stratum spinosum
- ) stratum granulosum
- ) stratum lucidum
- ) stratum corneum
what layer of cells is the stratum germinativum?
what cells make up this stratum?
what do they attach to and by what?
- Deepest single layer of cells
- Combination of merkel cells, melanocytes, keratinocytes, and stem cells that divide repeatedly
- cells attached to each other and to basal lamina by desmosomes and hemidesmosomes
What two layers does the stratum germinativum connect?
dermis and epidermis
How many cell layers thick is the stratum spinosum?
8-10
What happens in the stratum spinosum?
melanin taken in by phagocytes from nearby melanocytes. During slide preparation, cells shrink and look spiny
How many layers thick is the stratum granulosum?
are these cells dead or alive
3-5 layers of flat dying cells
What does the stratum granulosum contain and why is this important?
It contains dark-staining keratohyalin granules. This is important because these granules release lipid that repels water. It makes the cells oily so water can’t come in or out
**so skin can’t go bad (butter analogy)
Where is the stratum lucidum located?
How many layers of cells?
seen in thick skin on palms and soles of feet only
3-5 layers of clear, flat, dead cells
How many layers thick is the stratum corneum? describe the cells in these layers
25-30 layers of flat dead cells filled with keratin and surrounded by lipids
What is the purpose of the stratum corneum?
barrier to light, heat, water, chemicals, and bacteria (protection)
friction of the stratum corneum stimulates ________ formation
callus
give 3 characteristics of thick skin?
- palmer and planter surface
- about 30 layers of stratum corneum
- all 5 layers
give 3 characteristics of thin skin
- rest of body surfaces
- fewer layers of stratum corneum
- no stratum lucidum
what is another name for fingerprints?
epidermal ridges
what stratum forms these ridges that extend into the dermis?
germinativum
Why are epidermal ridges important?
they increase the surface area and friction therefore increasing the grip in hands and also in feet
melanocytes release vesicles called ___________ into keratinocytes
melanosomes
True or False:
Everyone has a similar number of melanocytes
true
the amount of pigment produces by melanocytes is determined by 2 factors……
- ) genetic control
2. ) respond to melanocyte stimulating hormone
What increases melanin production?
UV light
a little UV converts a steroid precursor in the skin into what?
too much UV can do what?
- vitamin D
- too much can damage chromosomes and cause 1st degree burns
Melanin production in people is directly correlated to……
latitude where the population is indigenous
Melanocytes convert ______ to melanin
tyrosine
Black or brown melanin is called what?
Red-brown melanin is called what?
eumelanin
pheomelanin
describe Carotene
- yellow-orange pigment (precursor of vitamin A)
- found in stratum corneum and subcutaneous
describe hemoglobin
red, oxygen carrying pigment in blood cells
-if other pigments are not present, epidermis is translucent so pinkness will be evident
What are the two layers of the dermis?
Papillary layer and Reticular layer
what three things make up the papillary layer?
areolar connective tissue
capillaries and neurons
dermal papillae
describe the reticular layer of the dermis
- anchoring layer
- large vessels, nerves, adipocytes, arrector pili muscle
- dense irregular CT
(collagen: strength
elastic: strength, flexibility)
What is the cutaneous plexus and where is it located?
- network of arteries and veins supplying skin with blood
- located in subcutaneous layer
What does the papillary plexus do? where is it located?
- helps nourish epidermal layer
- follows epidermal/dermal boundry
Lines of Cleavage
look at slides
What connective tissues and fibers are located in the hypodermis?
CT: areolar, adipose
Fibers: collagen, elastic
True or False:
the hypodermis is a bad insulator
false;
adipose acts as a good layer (layer of fat)
What else is located in the hypodermis?
major blood vessels and nerves
what does the hypodermis do?
stabilizes the skin
hair is located on most surfaces except….
plantar/palmer
parts of digits
lips
eyelids (except eyelashes)
What are the three types of hair?
Vellus: “peach fuzz”
Terminal: thicker with darker pigment
Intermediate: arms
The part of the hair that you can see is called the….?
shaft
the base of the hair follicle is the….?
bulb
the _______ part of the hair penetrates into the dermis
what surrounds this part?
root
hair follicle
each individual hair consists of 3 things:
cuticle
cortex
medulla
what are the functions of hair?
protection
reduction of heat loss (more accessory)
sensing light touch
What is the purpose of the Root hair plexus?
has sensory nerves surrounding the follicle that detect hair movement
what is the Arrector Pili?
smooth muscle that moves hair (goosebumps)
What are the 3 stages of hair growth? describe them
Anagen: may last up to 6 years depending on the body part; matrix cells at base of hair root producing length
Catagen: lasts up to 2 weeks; matrix cells inactive and follicle atrophies (no growth)
Telogen: hair follicle remains dorment; hair is eventually pushed out by new hair as cycle renews
hair color is the result of________
melanin produced in melanocytes in hair blub
what kind of melanin is located in these hair colors: Brown/Black Blonde Red Gray
Brown/Black: large amounts of eumelanin
Blonde: little eumelanin
Red: high relative pheomelanin
Gray: decline in all melanin production
What are the 4 specialized exocrine glands found in the dermis?
sebaceous (oil) glands
Sudoriferous (sweat) glands
Ceruminous (wax) glands
Mammary (milk) glands
What does sebacous glands secrete?
how do these secrete this?
what does this secretion do?
sebum
holocrine secretion
decreases evaporation and bacterial growth
where is sebum released if there is hair?
what if there is no hair?
hair: released into the follicle
no hair: secreted onto epidermis
What are sudoriferous glands?
sweat glands that are coiled tubular glands
what are the two types of sudoriferous glands?
merocrine and apocrine
describe merocrine sweat glands
- Use merocrine system of exocrine secretion
- on most body surfaces (greatest on palms)
- not associated with hair follicle
- watery secretion called sensible perspiration made of water, urea, and NaCl
- function: cooling, excretion, protection
describe apocrine sweat glands
- use the merocrine system of exocrine secretion
- associated with hair follicle
- located in axillae, areolae, groin
- produces viscous secretion starting at puberty
- Functions: reduce friction, cooling, secrete pheromones
What are 2 modified apocrine glands?
Mammary (lactiferous) for milk production
Ceruminous in external ear (secretion mixes with sebu to create ear wax)
What are the 4 different parts of the nail
- nail body: keratinized, plate-like structure
- nail bed: surface of skin that covers nail body
- nail root: source of nail production
- lunula: whitish, half-moon region at base of nail plate due to obscured blood vessels
What is the purpose of having nails?
to scratch
manipulate environment
protect hand/feet
to counteract pressure put on connective tissue
What are burns?
tissue damage and cell death caused by heat, electricity, UV radiation, or chemicals
what are three associated dangers with burns?
dehydration
electrolyte imbalance
circulatory shock
describe the three types of burns
1st: skin red and swollen, only epidermis damaged
2nd: skin red with blisters; epidermis and upper dermis damaged
3rd: gray-white or black; destroys entire layer (no skin)
what percent of your body must have 3rd degree burns to kill you?
what about 2nd?
10%+ for 3rd degree
25%+ for 2nd
what are characteristic effects of aging?
less hair reduced blood supply dermis tends to thin drying of epidermis fewer melanocytes
