The skin has three layers - the epidermis, dermis, and hypodermis. The epidermis is the outermost layer and contains keratinocytes that produce keratin and melanocytes that produce melanin, which determines skin color. The dermis is the thick middle layer containing blood vessels, nerves, hair follicles, and glands like sebaceous glands that produce oil and sweat glands that produce sweat. The innermost hypodermis layer is made of fatty tissue that regulates body temperature and connects the skin to muscles.

1. LESSON 4.3

2. WHAT IS THE SKIN?
• The skin is the largest organ in our body.
• It covers the body's entire external surface.
• It protects the body.
• It holds body fluids in.
• The skin is full of nerves so you can feel hot and cold
• It has three layers called the: Epidermis, Dermis, and
Hypodermis.

3. THE OUTER LAYER OF THE SKIN
-The outermost layer of the skin is known as the epidermis.
- The epidermis layer has keratinocytes or cells that produce keratin
and melanocytes or cells that produce melanin.

4. THE OUTER LAYER OF THE SKIN
-It protects the skin from being damaged by
being a waterproof barrier that prevents the entire body from
being soaked up.
-Its a cell that is produced by keratinocytes

5. THE OUTER LAYER OF THE SKIN
-Melanin serves as the barrier that protects the skin from the sun’s harmful rays.
-The amount of melanin produced in one’s skin determines the skin tone of the person.
A darker skin tone means that the person has skin that produces more melanin. While a
person with less melanin has fair to white skin.
-When alot of melanin is produced, You have dark skin.
But if the melanin is produced less, you have lighter
skin.
-Its produced by melanocytes
Fig. 1. White Skin to Dark skin caused by melanin

6. THE OUTER LAYER OF THE SKIN
DID YOU KNOW?
ALBINISM is a disease in which a person has partial or complete
loss of melanin in the skin, eyes, and hair.
Because of this condition, an individual
having this disorder has brighter skin
compared to most people. Their hair also
tends to be white.
Fig. 2. An albino girl

7. THE MIDDLE LAYER OF THE SKIN
Below the epidermis and the thickest layer of the skin is the dermis. The blood vessels,
nerves, hair follicles, and glands are found here. Glands are tiny organs that release
substances important for the body to function. The skin has two glands, sebaceous
glands and sweat glands.
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8. THE MIDDLE LAYER OF THE SKIN
-Sebaceous glands or oil glands produce sebum or oil that makes the skin
soft and waterproof.
-When oil glands produce too much oil, debris and bacteria may gather and
block the follicles. This plug that forms from the oil and dirt is commonly
called a pimple.
-Thus, it is important to wash your face to keep it free from excess oil, dirt,
and bacteria.
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9. THE MIDDLE LAYER OF THE SKIN
-Sweat glands produce sweat or perspiration that allows the body to cool
down.
-Sweat is a naturally odorless substance. Bacteria that can live harmlessly
on our skin like warm, moist areas like the armpits, eat the sweat and
produce an unpleasant smelling odor afterward. This process is what
causes body odor.
-Maintaining good hygiene such as taking a bath
regularly and changing from sweat-drenched clothes can help reduce
chances of body odor.
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10. THE MIDDLE LAYER OF THE SKIN
For people who sweat excessively especially in the armpits, the use of
deodorant or antiperspirant is recommended.
● Deodorants can reduce body odor by making the armpits acidic,
which is less preferred by bacteria.
● Antiperspirants reduce excessive sweating by blocking the passage
of the sweat outside the glands.
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11. THE MIDDLE LAYER OF THE SKIN
-Almost all parts of the body are covered with hair. Hair follicles are tiny
bulbs in the dermis where hair grows.
-Tiny muscles attached at the base of the hair follicles contract when the
skin senses cold as an attempt to help trap heat. The contraction of these
tiny muscles
makes the hair in the skin stand on one end, and it is commonly known as
goosebumps.
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12. THE MIDDLE LAYER OF THE SKIN
The dermis also has tiny sensors called nerves. The nerves allow the person
to feel different sensations when the epidermis is touched.
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13. THE MIDDLE LAYER OF THE SKIN
Blood vessels allow oxygen and food carried by the blood to reach the skin.
They help the skin regulate your body’s temperature.
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14. THE INNER LAYER OF THE SKIN
The last layer is a layer of fatty tissues known as hypodermis. It is also
known as the subcutaneous layer, which means “beneath the skin.” It is a
layer of fats that helps regulate the temperature of the body. Since this
layer is the innermost layer, it connects the skin to the muscles.
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15. PARTS AND LAYERS OF SKIN LEARNED
CONGRATULATIONS! You have learned the parts and layers of the skin! Lets
move on now to the Diseases!
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