QUIZLET WITH ALL U2 LECTURE CONTENT (more in depth and has vocab terms)
Integumentary System Overview
Structure and function of the appendages of the dermis: hair, sebaceous glands, and sudoriferous glands.
Function of Hair: Protection, temperature regulation, protects scalp from UV radiation.
Structure: Made of keratin and grows from the hair follicles located in the dermis.
-the shaft (the visible part above the skin)
-the root (the part embedded in the follicle)
-bulb (the base of the root where growth occurs)
The follicle surrounds the root and is connected to various structures, including sebaceous glands and tiny muscles called arrector pili.
Function of Sebacous Glands: These glands make an oily substance called sebum which helps waterproof both skin and hair. It also helps prevent dryness and friction and protect against bacteria and fungi.
Structure: Sebaceous glands are small glands located in the dermis that are usually associated with hair follicles. Sebaceous glands are more abbundant in the scalp and face.
Function of Sudoriferous Glands: Thermoregulation through sweating (helps the body cool down with a clear fluid when it is hot).
Structure: Sudoriferous glands (sweat glands), found in the dermis and come in two types:
-Eccrine glands: Everywhere in the body
-Apocrine glands: Concentrated in the armpits and groin, these ones can contribute to body odor.
What is melanin's function? In what type of cell is it produced, and in what type of cell does it function in the skin? Explain the balance of nutrient deficiency protections associated with diverse skin tones.
-Melanin serves as protection against UV radiation- UV radiation can make vitamin D but too much can cause harm to our DNA and break down folic acid
-Melanin is produced in melanocytes
-Keratinocytes help as well with function:
keratinocytes in stratum spinosum
melanocytes has several arm-like extensions that protrude up into stratum spinosum, deliver melanosomes to keratinocytes (melanosomes = vesicles filled with melanin).
in keratinocytes, melanin positions itself above nuclei, forming ~ umbrella at the apical surface of each cell in which it is functioning.
lysosomes in keratinocytes that degrade melanosomes - activity of lysosomes varies across skin tones (more active degrading melanosomes in lighter skin tones vs less active in darker skin tones)
-Melanin can be released into keratinocytes or melanin can stay in melanosomes
-If you are genetically from further away from the equator-your skin tone is lighter, meaning that you might have a vitamin D deficiency
-The lighter skin makes it easier for UV rays to penetrate it to help execute vitamin D production
-If you are closer to the equator you have a darker skin tone to help protect the over exposure of UV rays and the damage of folic acid
-The goal here is to find a balance between making vitamin D and reducing the destruction of folic acid.
The structure (cells and other characteristics) and function of the specific layers of the epidermis.
The Epidermis Cells:
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Keratinocytes: most common cell in epidermis
Produce keratin and house melanin so it can function
Melanocytes: dark in pigment b/c they produce melanin
Produce melanin(dark brown pigmented protein-protection against UV rays)
Stem Cells: Divide to create keratinocytes
Tactile cells: Sensory receptors in the epidermis
Dendritic Cells: branching to increase surface area
Derived from macrophages so they patrol for pathogenic invaders
Listed deep to superficial:
1.Stratum Basale: Single layer of cells at the base of the epithelium
Keratinocytes, melanocytes, tactile cells, stem cells, most protected layer within the epidermis
2.Stratum Spinosum: Multiple layers of cells, 2nd layer from the base-keratinocytes, dendritic cells
3.Stratum Granulosum: multiple layers of cells starting to flatten out
ALL keratinocytes starting to have visible vesicles, keratohyalin granules: contains proteins that are essential for making keratin-signals that keratin in keratinocytes is almost ready
Then the keratinocytes die and become sacs of keratin
KERATIN is strong and waterproofing, made out of intermediate filaments
Lamellar vesicles: contain an oily and waxy substance that gets secreted on top of keratinocytes-waterproofs and helps seal the cracks between the dead cells- it causes cells to die b/c the waxy oil cuts the cell off from nutrients
-If it is thick skin there will be a stratum lucidium- and its all dead keratinocytes
4. Stratum Corneum: Is the most superficial layer everywhere- it has all dead keratinocytes sloughing off to be replaced by cells in deeper layers
-The overall function is to help with water proofing and prevent water loss, infection, chemical exposure, and uv radiation
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