Session 5.1a - Pre-Reading - Skin Functions Flashcards
https://www.youtube.com/watch?v=sEqSFWjj2_Q Function of the Skin
What is the largest organ of the body?
Skin
Skin is the largest organ of the body by what ___
Mass and size
What type of organ is the skin?
A multifunctional organ
What is a multifunctional organ?
A set of tissues that work together to carry out a certain set of functions
Name the functions of the skin.
7 functions
1) Protection
2) Sensation
3) Thermal Regulation and Insulation
4) Excretion and Secretion
5) Immunity
6) Endocrine
7) Growth
What is the outermost portion of the skin called?
Epidermis
What is found in our epidermis?
Four specialised cells
What are the 4 specialised cells of the epidermis?
- Keratinocytes
- Melanocytes
- Langerhans cells
- Merkel cells
What is the middle section of our skin called?
Dermis
What does our dermis contain?
- Blood vessels (arteries and veins)
- Excretory glands e.g. sebaceous (oil) gland, sweat gland
Where are the arteries of our skin located?
The dermis
Where are the veins of our skin located?
The dermis
Where are our excretory glands located?
Dermis
Where do we find keratinocytes?
Epidermis
Where do we find melanocytes?
Epidermis
Where do we find Langerhans cells?
Epidermis
Where do we find Merkel cells?
Epidermis
Give 2 examples of excretory glands found in the dermis.
Sebaceous (oil) gland
Sweat gland
What does sebaceous mean?
Relating to oil or fat
- Relating to a sebaceous gland or its secretion
What does a sebaceous gland do?
Exocrine glands which secrete oily or waxy matter.
What is the lowest portion of the skin?
Hypodermis
Name the layers of the skin.
Epidermis
Dermis
Hypodermis/subcutaneous layer
(from superficial to deep)
Label these in order of superficial to deep.
Dermis, Epidermis, Hypodermis
Epidermis
Dermis
Hypodermis/subcutaneous layer
(from superficial to deep)
What is the hypodermis also known as?
The subcutaneous layer
Which layer does the subcutaneous layer of the skin correspond to?
The hypodermis
What does the hypodermis/subcutaneous layer contain?
Adipose cells
Macrophages
Where are adipose cells found?
Hypodermis/subcutaneous layer
Where are macrophage cells found?
Hypodermis/subcutaneous layer
What is the function of adipose cells?
To insulate our body
Which cells function to insulate our body?
Adipose cells
What is the function of macrophages?
To engulf bacterial cells
Which cells engulf bacterial cells?
Macrophages
What is arguably the most obvious function of the skin?
Protection
How does the skin provide protection?
Skin creates a physical barrier that protects us from a wide range of harmful things
What do keratinocytes do?
Secrete a protein fibre called keratin
Where is keratin secreted from?
Keratinocytes in the epidermis
What sort of molecule is keratin?
A protein fibre
What is the function of keratin?
- Gives skin strength
- Protects skin from water (makes skin impermeable to water)
How does keratin protect skin from water?
It makes it impermeable to water.
What fibres are found in the dermis?
A network of collagen and elastin fibres (also in the hypodermis)
Where are collagen fibres found?
In the dermis and hypodermis
Where are elastin fibres found?
In the dermis and hypodermis
What fibres are found in the hypodermis?
A network of collagen and elastin fibres (also in the dermis)
What do keratin, collagen and elastin work together to do?
Give the skin strength and elasticity
What gives the skin strength and elasticity?
Keratin, collagen and elastin
What does having strength and elasticity allow the skin to do?
Resist physical and mechanical pressures and forces.
How does the skin resist physical and mechanical pressures and forces.
Strong and elastic protein fibres such as keratin, collagen and elastin, found in the dermis/hypodermis of the skin, gives the skin strength and elasticity. This is able to resist physical/mechanical pressures/forces.
What types of fibres are keratin, collagen and elastin?
Strong and elastic protein fibres
Name 3 strong and elastic protein fibres.
Collagen
Keratin
Elastin
What is the relationship of the skin to our internal organs?
Ensures they are well protected and not damaged
How does the skin protect the heart (for example)?
The heart is not only protected by the sternum bone and the rib cage, it is also actually protected by the layer of skin that exists on top of our sternum and ribcage
Name 5 things the skin protects us from.
- Physical damage
- Excessive UV radiation
- Bacterial and viral microorganisms
- Dehydration
- Dangerous chemicals
Why do we need the skin protect us from UV radiation?
Excessive UV radiation is dangerous
Do we need UV radiation?
Excessive UV radiation is dangerous but our skin actually needs UV radiation to ultimately synthesise vitamin D
What does our skin use UV radiation for?
Synthesising vitamin D
How is vitamin D synthesised?
In the skin via UV radiation
What is vitamin D?
A hormone that is used to basically regulate calcium and phosphate ions in our blood
Which hormone used to regulate calcium and phosphate ions in our blood is synthesised from UV radiation?
Vitamin D
What is UV radiation?
UV radiation is a type of electromagnetic wave and it carries more energy than normal visible light waves, and that’s because it has a slightly higher frequency
Why is excessive UV radiation dangerous?
When UV rays (high-energy rays) hit the cells of our skin they can end up damaging the organelles and the biological molecules, such as DNA found inside our skin cells
What biological molecules can UV radiation damage?
Organelles and DNA found inside skin cells.
What can excessive UV radiation ultimately lead to?
Cancer
How can excessive UV radiation ultimately lead to cancer?
UV rays are high-energy, so when these rays hit the cells of our skin, our DNA and organelles of the skin are susceptible to damage. Damage to the DNA can ultimately lead to cancer.
What natural defence do we have against UV radiation?
Melanocytes (specialised cells found in the epidermis), which release melanin
Which layer of skin protects us from UV radiation?
Epidermis - melanocytes found there.
What do melanocytes do?
Release a chemical/pigment known as melanin
What type of molecule is melanin?
A chemical/pigment
What is the function of melanin?
- Gives us our skin colour
- Absorbs UV radiation which protects us from damaging our skin
What gives us our skin colour?
Melanin released from melanocytes in the epidermis of our skin.
What absorbs UV radiation protecting us from skin damage?
Melanin released from melanocytes in the epidermis of our skin.
How does the skin prevent bacterial cells and viral agents getting into our body?
By creating a physical barrier
What is the skin a physical barrier against?
Bacterial cells and viral agents
Other than bacteria and viral miroorganisms, what else does the skin protect us from?
A wide variety of different types of harmful chemical agents
How does the skin protect us from dangerous molecules?
If some type of harmful molecule gets onto our skin, there is a very high probability that the skin will not allow that harmful chemical to actually go through the skin and into our organs found inside our body.
Explain how the different layers of the skin aid in protection.
Epidermis - keratinocytes secretes keratin which makes the skin strong and impermeable to water
- melanocytes release melanin which protects us from UV radiation
Dermis - network of collagen and elastin which (together with keratin) gives skin strength and elasticity, allows the skin to resist physical/mechanical pressures/forces
Hypodermis - collagen and elastin also found here.
How is the epidermis involved in protecting the skin?
- keratinocytes secretes keratin which makes the skin strong and impermeable to water
- melanocytes release melanin which protects us from UV radiation
How is the dermis involved in protecting the skin?
Network of collagen and elastin which (together with keratin from the epidermis) gives skin strength and elasticity, allows the skin to resist physical/mechanical pressures/forces. This also occurs in the hypodermis.