Integumentary System Flashcards
Integumentary system consists of..
- skin
- glands
- hair
- nails
- nerves
2 layers of the skin
- Epidermis
- Dermis
Epidermis is.. and its major tissue and sub tissue
- Epithelial tissue derived from the ectoderm
- stratified squamous epithelium
Epidermis is avascular or vascular
avascular
Epidermis separated in to..
5 strata based on cell types
5 strata of epidermis
- stratum basale
- stratum spinosum
- stratum granulosum
- stratum lucidum
- stratum corneum
Stratum basale
- single row of cells.
- The basal layer (bottommost, deepest layer, furthest from the outside)
- where you sunburn/produce melanin
2 cell types of basale
- kerantinocytes (90%)
- melanocytes (8%)
Kerantinocytes
undergo mitosis**, make keratin, migrate to surface as new cells produced in basale
Melanocytes
produce pigment for UV light protection,
cells produce different amounts/shades of melanin (skin color)
Stratum spinosum
(look spiney) limited cell division occurring
- Several cell layers thick
- many keratinocytes layered atop of one with melanin granules scattered throughout
Stratum granulosum
- contain dark granule
- 3 to 5 cell layers thick
- all cells above this layer (closer to the surface of the body) are too far above the blood supply to maintain life
Stratum lucidum
- flat dead cells
- visible in only thick* skin
- 2 to 3 layers
- appears as a clear band of cells with indistinct boundaries under the microscope
Stratum corneum
- 30 layers of flat dead cells filled w/ keratin surrounded by waterproofing glycolipid.
- shed and replaced by cells from mitosis below
- outer most layer
- function in protection* and moisture
Dermis consists of what cells and how large is it
fibroblasts (make matrix), fibrocytes (protect matrix) and matrix
VERY large compared to epidermis
2 sublayers of dermis
- Papillary
- Reticular
Papillary layer
directly under epidermis
loose areolar CT,
vascular
has projection into epidermis (dermal papillae)
Reticular layer
deepest layer away from skin surface
most of dermis (80%)
dense irregular CT (can be stretched)
(stretching can cause striae which is stretch marks)
Hypodermis
- NOT part of the dermis
- subcutaneous layer
- superficial fascia binds the skin to muscle
- adipose CT tissue below skin (50% of adipose is here)
Melanin is found within the…
stratum basale and the stratum spinosum of the epidermis
Thin and thick skin refers to..
epidermis
Thin skin
- lucidum not apparent
- has hair follicles, sebaceous glands, arrector pili muscles
- everywhere but hands and feet
Thick skin
- (palm of hand and sole of foot)
- lucidum visible,
- no hair follicles, sebaceous glands, or arrector pili muscles
- no oil production but can sweat
Epidermal derivates
- hair
- nails
- exocrine glands
Parts of hair
- root
- shaft
- hair follicle
Hair root
- found below the skin surface
- Keratinization is still ongoing
- Found deep within the follicle
Hair shaft
- projects above the skin surface
- Keratinization is complete here
Hair follicle
-down from the epidermal surface into the dermis
Expanded region at deepest point of hair follicle is called.. and contains..
the hair bulb
Contains a knot of capillaries that supplies nutrients to the growing hair and signals it to grow
The hair matrix is the actively dividing the area of the hair bulb and produces
the hair
Associated with each hair follicle is..
- root hair plexus (nerve ending)
- sebaceous (oil) gland
- arrector pili muscle
How sweat evaporates from the skin to cool off
- then heat from the body is used to break hydrogen bonds between water molecules in sweat
- This heat is no longer available to warm the body
- Water molecules evaporate when hydrogen bonds no longer hold them on the skin surface
What part of nail is responsible for growth
nail matrix
Nails are made of
heavily keratinized epidermal cells found within the stratum corneum
Nails consist of..
- proximal root
- nail body
- free edge
4 types of skin exocrine glands
- sebaceous glands
- sudoriferous glands
- ceruminous glands
- mammary glands
Sebaceous glands
connected mainly to hair follicles, secretes sebum
Sebum
oil (mix of fats, salt, proteins)
softens, lubricates hair and skin
prevents drying out (water loss)
antibiotic properties
Sudoriferous glands produce ..
sweat
Sudoriferous glands act to..
- cool body down
- antibiotic function (lysozyme break down bacteria)
- removes waste (urea)
Ceruminous glands
modified sweat glands in ear canal
produce ear wax
Mammary glands
modified sweat glands, produce milk
Cutaneous sense receptors
nerve endings form from the end of sensory neurons
Cutaneous sense receptors
found in the skin
Respond to stimuli such as touch
4 varieties of cutaneous sense receptors
- touch receptors
- pressure receptors
- thermoreceptors
- nocireceptors
Touch receptors
free nerve endings in epidermis
root hair plexuses which wraps around hair follicle (not encapsulated)
messiness corpuscles in dermal papillae
Pressure receptors
free nerve endings
pacinian corpuscles deep in dermis of hypodermis
Themoreceptors
free nerve endings for temperature
more nerve endings for cold
Nociceptors
free nerve endings for pain function for protection (makes you aware)
Dermal ridges in the papillary layer form..
finger prints
Melanin found in 2 forms that
that range in color from yellow to tan to reddish brown to black
Albinos are..
unable to produce melanin
Pink tinge
seen in fair skinned people, comes from hemoglobin found within the vascular dermal layer of the skin
