ch 5 - integumentary system Flashcards
2 parts of the integumentary system
- cutaneous membrane (skin) - epidermis and dermis
- accessory structures: hair, hair follicle, nails, glands
3 layers of the skin
epidermis
dermis
hypodermis
integument functions (4)
- protection - acts as physical and chemical barrier
- excretion - removes wastes through sweat
- thermoregulation
- melanin production
epidermis
top layer of skin made of stratified squamous epithelium tissue
2 types of skin in epidermis
thick and thin
thin skin
has 4 layers in the epidermis, covers most of the body
thick skin
has 5 layers in the epidermis, found on palms of hands + soles of feet
keratin
double protein that makes hair and nails
keratin function
protects tissue of skin; made of tough protein fiber
epidermis sublayers
Can Lemurs Get Some Bamboo
stratum basale
stratum spinosum
stratum granulosum
stratum lucidum
stratum corneum
stratum basale
- deepest layer where cell division takes place
- attachment to basement membrane
- contains basal cells, melanocytes and tactile cells
stratum spinosum
-2nd deepest layer of epidermis
-has 8-10 layers of keratinocytes bound by desmosomes and contains langerhans cells
stratum granulosum
-3-5 layers of flattened dying keratinocytes that produce keratin
stratum lucidium
- appears as glassy layer in thick skin only
- 4-6 layers of flattened dead keratinocytes,
stratum corneum
top layer
- has dead cells continually shedding and being replaced
- water resistant, not waterproof
types of water loss from skin (2)
- insensible perspiration: evaporative water loss, cant be seen or felt
- sensible perspiration: sweating
dermis
deeper layer of skin located under epidermis
- made of connective tissue with collagen and elastic fibers
2 layers of the dermis
papillary and reticular
papillary layer
top layer of dermis that is thinner and made of loose areolar tissue
papillary layer function
nourishes and supports epidermis
reticular layer
deeper layer of dermis that consists of dense irregular connective tissue, rich in collagen and elastic fibers
reticular layer function
has sensory receptors that detect touch, pain, pressure, vibration
- blood vessels assist in thermoregulation
tension lines
pattern produced by parallel bundles of collagen and elastic fibers in the dermis
clinical significance of tension lines
- cuts made parallel to tension lines stay closed and heal with minimal scarring
-Cuts made perpendicular to tension lines lead to more scarring
branch of arteries within the subcutaneous layer form the following 2 networks:
- cutaneous plexus
- subpapillary plexus
subcutaneous layer
stabilizes position of the skin and connects the dermis to underlying tissues
melanin
red/yellow or brown/black pigment produced by melanocytes
carotene
orange/yellow pigment that accumulates in epidermal cells
skin color is affected by
amount of melanin production not number of melanocytes (we all have same # of melanocytes)
cyanosis
bluish coloration of skin due to deoxygenated blood
hemoglobin
binds and transports oxygen in the bloodstream
vitiligo
loss of melanocytes which result in white patches in skin
albinism
inherited genetic disorder with individual having an inability to produce melanin
accessory structuress
hair, nails and glands
hair
keratinous strand produced by epithelial cells of the hair follicle
hair root
portion of hair that anchors the hair into the skin
hair shaft
extends from end of hair root to the exposed top of the hair
- above the skin
longitudinal layers of hair
cuticle, cortex, and medulla
hair follicle
tube lined by stratified squamos epithlium, sac where the hair grows
- has nerve (hair root plexus) supply
hair root plexus
sensory nerves surround the base of each hair follicle
hair bulb
onion shaped based that surrounds hair papilla
hair papilla
connective tissue containing (blood vessels) to nourish the hair follicle
arrector pili
involuntary smooth muscle whose contractions causes hairs to stand up
epidermal growth factor function
Stimulating repair of the epidermis after injury
Stimulating division of cells in stratum basale
Accelerating keratin production
Approximately how long does it take for a cell to move from the stratum germinativum to the stratum corneum?
7-10 days
Differences in skin color among individuals are the result of
the different levels of melanin synthesis
Psoriasis is a skin disorder in which there is abnormal increased mitotic activity in the
stratum basale
The cell of the epidermis that detects tactile sensations is the
merkel cells
The cell of the epidermis that are macrophages is the
Langerhans cell
The most common type of skin cancer is
basal cell carcinoma
What type of skin cancer is more likely to be malignant?
melanoma
melanoma
aggressive cancer of the melanocytes (melanoyctes grow out of control)
Rule of 9’s to calculate the percentage of area burnt on a body?
head - 9%
Each upper limb is 9%
The trunk is 36%, back is 18, front is 18%
Each lower limb is 18%
Genitalia are 1%
basal cell carcinoma
most common type of skin cancer
- cancer that begins in the stratum basale
