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FUNCTIONS OF THE SKIN
I only realized the importance of the sense of touch after the doctor told me that I might lose it. Our sense of touch takes on such an important role in our lives. Yet many of us take it for granted and do not see that the skin is actually vital to us.
Here are 10 functions of our skin:
1) Protective layer
- defense from the external environment
2) Sensation:
- sense of touch
3) Heat Regualtion:
- dilation and constriction of blood vessels and shunt vessels.
4) Controls rate of evaporation:
- prevents excessive water loss
5) Storage:
- stores lipids and water
6) Synthesis:
- synthesizes Vitamin D from UV rays
7) Excretion:
- sweat excretes small amounts of urea
8) Absorption:
- In humans, for certain forms of medication administration, such as adhesive patch. E.g. Nicotine patch
- in animals, their skin is their respiratory organ
9) Water resistance:
- a water resistant barrier
10) Aesthetics:
- affects how we look and the image we portray to others
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Structure |
Function |
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The Epidermis is the relatively thin, tough, outer layer of the skin. Most of the cells in the epidermis are keratinocytes. These cells slowly migrate up toward the surface of the epidermis. Once they reach the skin surface, they are gradually shed and are replaced by younger cells pushed up from below. |
EPIDERMIS |
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1 |
Hair
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Grows hair by packaging old cells together. Attached to it is a sebaceous gland and a sebum-producing gland. There are structures called papilla, made up of connective tissue and a capillary loop It is covered with epidermal cells and constantly divide to grow new skin cells. (Other structures include arrector pili muscle.)
It is attached to the hair follicle. When it contracts, it causes our hair to stand in its ends. Skin around the hair will be raised as well, resulting in what we commonly call ‘goose pimples’.
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The dermis is a thick layer of fibrous and elastic tissue that makes the skin flexible and strong. It is the skin's supporting tissue and is particularly rich in nerve endings. |
DERMIS |
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2 |
Sweat Glands
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It is a coiled tube which forms a tight knot, surrounded by many blood capillaries, from the down growth of epidermis.
Secreted sweat from the sweat glands flows through the sweat duct, then the swear pore, which is an opening to the surface of our skin.
Secretes sebum
Consists of water, dissolved salts, and small amounts of urea (excretes small amounts of metabolic waste product) |
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3 |
Sensory Receptor
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Gives the sensation of touch
Modified dendrites of sensory neurons which allows us to sense pain, pressure and temperature changes in our surroundings.
They are mechanoceptors, responding to pressure, or any kind of mechanical stimulus causing a deformation of the corpuscle. |
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4 |
Nerve fibre |
Nervous impulses from the receptors move along the nerve fibre to the central nervous system to bring about a response. |
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5 |
Blood vessels |
They provide nutrients to the skin and help regulate body temperature. Heat makes the blood vessels enlarge (dilate), allowing large amounts of blood to circulate near the skin surface, where the heat can be released. Cold makes the blood vessels narrow (constrict), retaining the body's heat. |
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Below the dermis lies a layer of fat that helps insulate the body from heat and cold, provides protective padding, and serves as an energy storage area. The fat is contained in living cells, called fat cells, held together by fibrous tissue. |
HYPODERMIS |
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6 |
Sub-cutaneous fat |
Insulating layer for heat loss prevention which is made up of adipose cells (tissue) |
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Click here to learn more about receptor endings
my hand. Though it may be a small drop of oil, but it did hurt quite a lot. From there, I began to think about what allows me to feel pain, and how I am able to feel it. More interestingly, I wanted to find out how I am able to feel the difference between a drop of burning hot oil, and an ordinary drop of water. From these thoughts, I started my research, surfing the internet and reading up. Firstly, the nerve fibres, also known as nociceptors, beneath our skin will detect the sudden increase in temperature of the burnt area of skin. They respond to touch, pressure, vibrations and temperature by sending nervous impulses. The nervous impulses transmit messages by sending electrical impulses along a peripheral nerve to the spinal cord and brain.
pain messages — such as the pain from the burn — will enter the spinal cord in an area called the dorsal horn. There, chemicals, also known as neurotransmitters, are released. They activate other nerve cells in the spinal cord, which processes the information and then continues to transmit the information about the burn to the brain.
The thalamus is a sorting and switching station deep inside the brain. Finally, when the neurotransmitters have reached the brain, it forwards the message about the burn to specialized regions of the brain, all at the same time. The brain would then respond to the pain by sending messages that moderate the pain in the spinal cord.
Simply put, pain is transmitted from nociceptors to the spinal cord, to release neurotransmitters, which transmits the message to the thalamus in the brain, where the brain will then respond.
Now that I know what allows me to respond to pain, I started searching about burns.
I found out that there are burns are classified
according to how serious they are, and how much damage is done to the nerves, tissues, and even fats.
Burns can be classified into 3 different groups:
1) Superficial burns (first-degree burns)
- Epidermis affected
- Nerves are not affected
- Reddened skin
- Pain is felt at the area of the burns
- E.g. Sunburn
2) Partial-thickness burns (second-degree burns)
- Epidermis destroyed, parts of dermis affected
- Nerves not damaged
- Skin becomes red and raw, blisters develop
- Intense pain felt
- E.g. Scalding
3) Full-thickness burns (third-degree burns)
- All layers of skin destroyed
- Nerves are totally damaged
- Charred, waxy skin
- Pain not felt where skin is charred
- Pain felt around area of charred skin
- E.g. Electric burns
So now I know that I have a partial-thickness burn. After providing treatment for the burn, I found out some interesting information while researching and comparing superficial burns and partial-thickness burns with full-thickness burns. Pain can be felt for the less serious burns, superficial burns and partial-thickness burns, but pain would not be felt for full-thickness burns.
The reason behind this is actually quite simple. In a superficial or partial-thickness burn, the nociceptors are working well, and are able to transmit nerve impulses to the brain to sense the pain. However, when a full-thickness burn occurs, the nociceptors have been burnt and damaged, and is no longer able to transmit messages to the brain. That is why pain is not felt in the full-thickness burn, which is much more serious than either a superficial burn or a partial-thickness burn.
Actually, feeling pain is not a bad thing. It is our body’s way to telling us that there is something dangerous, and we would be warned of the approaching danger. So, next time you’re wishing that your burn won’t hurt so much, you better think twice. Do you really want it to not hurt?
Audrey Wong-19-4H
http://www.umm.edu/dermatology-info/anatomy.htm
http://familydoctor.org/online/famdocen/home/healthy/firstaid/after-injury/638.html
http://www.nlm.nih.gov/medlineplus/tutorials/burns/er099102.pdf
http://www.mayoclinic.com/health/pain/PN00017
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