A&P- BIO 1110
Integumentary System Notes
General Characteristics:
The integumentary system includes the ___________ and its
___________________________.
What are the 3 parts to the skin?
The skin is the ____________ organ of the body.
o
Approximately 22 ft2
o
Approximately 16% of total body weight
o
0.5mm-4 mm thick
Thickest regions=
Thinnest regions=
Skin Functions:
Thermoregulation:
o
Most important function
o
Excess heat is carried to the skin by the blood vessels.
o
Skin absorbs heat and transfers it to the surrounding air.
Protection:
o
Works the best as a barrier when it is intact- no cuts, scrapes, etc..
o
Approximately ____ layers of cells.
A&P- BIO 1110
Integumentary System Notes
Sense organ:
o
Sensations of touch, vibration and pain
o
Collects information from the outside world and sends it to the brain
o
What parts of the body are the most sensitive?
Secretion and absorption:
o
o
Secretion:
Secretes ____________ and _____________ through glands.
What wastes can the skin remove?
Absorption:
Taking materials into the body through the skin.
Most absorbed- ____________________ vitamins (A, D, E, K)
Some toxins are absorbed- rubbing alcohol, acetone, chlorine
Vitamin D production:
o
When exposed to sunlight, the precursor becomes vitamin D because the
light energy transforms its shapes.
o
It takes hours of sun exposure to produce the amount of vitamin D in a glass
of milk. Is it worth it?
Epidermis: Outer Layer of Skin
What is the function of the epidermis?
Cells of the epidermis:
o
Keratinocytes
These cells make up _____ % of the epidermis
What is keratin?
A&P- BIO 1110
Integumentary System Notes
Most keratinocytes are _______
They don’t really become flattened until they reach the top layers
due to pressures from above and below as the cells move up the
epidermis.
o
What is keratinization?
Happens as cells move up through the epidermis
This is what eventually kills the keratinocytes
Melanocytes
What is the function of melanocytes?
Produce melanin-
It is produced by _______________ feedback. The more exposurethe more melanin produced- which means the more the skin can be
exposed to the sun.
We all have the same # of melanocytes per square inch of the skin.
Our melanocytes just produce a varying amount of melanin.
o
o
Langerhans cells
What is the function of Langerhans cells?
These are ________________________- engulf and destroy
Merkel cells
Function to gather information (touch, temperature, vibration, and
pain) and send it to the brain to be interpreted.
o
Melanocytes, Langerhans cells and Merkel cells account for the remaining
_____% of the epidermis.
Layers of the epidermis:
o
Stratum Basale
A&P- BIO 1110
Integumentary System Notes
Lies above the dermis and blood vessels in the dermis supply this
layer with blood (by diffusion)
Here is where _________________________takes place,
producing new skin cells and pushing older cells toward the surface.
o
Stratum Spinosum- superficial to the _______________________.
Cells have small projections “spiny” that help lock the cells together
like velcro.
o
Stratum Granulosum- superficial to the _________________________.
Cells are starting to look more squamous because of pressure from
the cells above and below.
Layer where _______________________ starts and cells produce
keratin in large quantities.
Can see granules of keratin in the cells.
The transition layer between __________________ and
__________ cells.
o
Stratum Lucidum- superficial to the ____________________________.
o
Only found on the ____________________________________.
Shock absorbers
Stratum Corneum- the most superficial layer of the epidermis
Spines start to break off which causes the cells to fall off
Waterproofs the skin
Takes ___________________ for cells to reach this layer from the
stratum basale.
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