Theme 1: The Integumentary System

Question 1

What is the integumentary system?

Answer 1

The Integumentary System is the outer barrier that provides protection from trauma, pathogens, radiation, heat, chemicals etc

Question 2

What is the 5 things in the integumentary system?

Answer 2

The Skin
Our Hair
Our Nails
Sweat glands
Oil glands (Sebaceous glands)

Question 3

Label this

Answer 3

A - dermal papilla
B - sebaceous gland
C - pacini corpuscle
D - arrector pill muscle
E - adipose tissue
F - hair shaft
G - epidermis
H - dermis
I - eccrine sweat gland
J - subcutaneous (hypodermis)

Question 4

What is the largest organ of the body

Answer 4

Skin

Question 5

What are the 6 functions of the skin?

Answer 5

1. ** Protection **- The skin acts as a protective barrier
2. ** Sense ** - The skin has structures that belong the our nervous system call receptors

3, ** storage of blood ** - bout 5% of your entire blood volume is retained in your skin at any given time, need more supply to an organ, your nervous system constricts your dermal blood vessels

4. ** Regulation of body temperature ** - he body can excrete about half a litre of sweat a day to keep you at a comfortable temperature,
5. ** Vitamin D **- t is the only vitamin the body can produce on it own. The skin cells contain molecule that coverts to vitamin D when it comes into contact UV light. Vitamin D is vital for the production of bone cells.
6. **Excretion of waste **. small amount of waste is eliminated via sweat.

Question 6

What is the three layers of the skin?

Answer 6

The Epidermis
The Dermis
The Hypodermis

Question 7

Label this

Answer 7

Question 8

What are the different layers of the injections?

Answer 8

Question 9

What is the physical barrier of the skin?

Answer 9

The skin regularly regenerates to maintain a waterproof and strong surface that can reduce harm.

The skin however is designed to let substances in, for example it will allow oxygen, carbon dioxide, fat-soluble vitamins and steroids which would prove useful. However, substances like solvents, drugs etc can also penetrate the skin, and they may not be desired.

Water can also be lost or gained through the skin

Question 10

What is the chemical barrier of the skin?

Answer 10

The skin is able to maintain a pH of 5.5 thanks to flora such as bacteria and fungi that live on the skin. It is impossible to avoid flora living on the skin, and the pH is a result of pathogens metabolising fatty acids and sebum on the surface of the skin.

Melanin is produced by melanocytes to protect the skin from UV exposure from sunlight.

Question 11

What is the biological barrier of the skin?

Answer 11

This is purely about immune protection from pathogens that could enter the skin. The epidermis contain dendritic cells whilst the dermis contains macrophages that act as a second line of defence against pathogens that have managed to get through the epidermis.

DNA is also present and it provides a natural protection against UVA and UVB rays in sunlight. Melanin and the stratum corneum provides further protection against UV rays.

Question 12

What is the epidermis?

Answer 12

The Epidermis is the most superficial layer of the skin that provides protection from physical, thermal and chemical factors. Interestingly, the epidermis is actually made up of a lot of dead cells

Question 13

What is this cells function?

Answer 13

The outer most layer of the epidermis that contains 25-30 layers of dead keratinocytes. It also contains keratin that provides a waterproof layer for the skin.
.

Question 14

What does this cells function?

Answer 14

he outer most layer of the epidermis that contains 25-30 layers of dead keratinocytes. It also contains keratin that provides a waterproof layer for the skin.

Question 15

What is the langerhans cells function?

Answer 15

often referred to as dendritic cells, these form part of the immune system that help with immune responses to external antigens that affect the skin. They help regulate production of antibodies that trigger macrophages to move in and destroy foreign pathogens. UV light can damage these cells.

Question 16

What do melanocytes do?

Answer 16

produces melanin which is a brown pigment designed to protect the skin from sun exposure. Melanin does not only impact skin colour, it also provide the colour to hair and the iris of the eyes. Melanin is more prominent in areas of the body such as the face, limbs, nipples and the penis. When melanin is produced, it is transferred to the keratinocytes. produces melanin which is a brown pigment designed to protect the skin from sun exposure. Melanin does not only impact skin colour, it also provide the colour to hair and the iris of the eyes. Melanin is more prominent in areas of the body such as the face, limbs, nipples and the penis. When melanin is produced, it is transferred to the keratinocytes.

Question 17

What do Merle cells do?

Answer 17

Merkel cells - these cells are in contact with sensory neurones and act as mechanoreceptors to help with the sensation of touch.

Question 18

What do the stadium granulosum do?

Answer 18

This layer of the epidermis contains keratinocytes that are very close to dying due to losing their nuclei. As a result, they start to flatten and disintegrate. As they disintegrate, they release granules that provide a water resistant lipid called lamellar granules, which is why this layer of the epidermis is particularly important to slow down water loss across the epidermis and prevent entry of pathogens.

Question 19

What is the Stratum Lucidum

Answer 19

The Stratum Lucidum - A thin layer of 2-3 rows of dead flat keratinocytes that help reduce any fluid loss through the skin. It is however only found in areas that require particular protection such as the soles of the feet and the palms of the hands.

Question 20

What is the spinous layer?

Answer 20

contains keratinocytes which can also be called prickle cells, as they develop spines on the surface which encourages the cells to pack together tightly. They are responsible for providing integrity, flexibility and strength to the skin.

Question 21

What is the stratum basal?

Answer 21

this is the deepest layer of the epidermis, and it is where new keratinocytes are regenerated through mitosis. Cells produce daughter cells which push cells above it upwards which causes this constant regeneration of the epidermis. There is a basement membrane which has high amounts of collagen that provides structural support for the epidermis and regulates the entry of cells and nutrients from the dermis to the epidermis.

Question 22

Are there blood vessels in the epidermis?

Answer 22

There are no blood vessels in the epidermis, instead oxygen and nutrients enter the epidermis through diffusion.

Question 23

What is the dermis responsible?

Answer 23

This part of the skin is primarily there to provide support and nutrients to the epidermis. It is a matrix of collagen, elastin and fibrous protein, holding within it major structures that contribute to maintaining skin health:

Question 24

What are the 7 things in the dermis?

Answer 24

Nerves
Hair follicles
Lymph vessels
Blood vessels
Sebaceous glands
Sweat glands
Smooth muscle

Question 25

What is the two layers of the dermis?

Answer 25

The papillary dermis and the reticular dermis

Question 26

What is the papillary layer of the dermis?

Answer 26

ayer sits below the basement membrane that sits underneath the epidermis.

This connective tissue is made up of a combination of collagen (to provide strength) and elastic fibres (to provide stretch and recoil ability).

White blood cells such as phagocytes can also be found in high numbers within small blood vessels to provide additional protection against pathogens.

Question 27

What is the reticular layer of the dermis?

Answer 27

The reticular layer accounts to about 80% of the dermis.

It contains thick bundles of collagen which help provide the skin the strength it needs to protect us from external damage.

There is also elastic fibres within the reticular layer that helps provide the skin with it’s recoil ability, the ability to regain it’s shape after stretching

Will degenerate with sun and age

Question 28

What are the cleaver / langer.s line

Answer 28

invisible lines of collagen fibres that run longitudinally to the skin.

These lines are particularly important for surgeons to know about, as correct incisions running along the cleavage lines can promote better healing of wounds

Question 29

What are nails made from?

Answer 29

Nails are made from the nail matrix which produces cells that will harden and move from the nail root to the nail plate.

We can see the nail matrix as the white patch near the bottom of the nail, which is called the lunula (see diagram below to help).

Question 30

What is the nail matrix made up of?

Answer 30

The nail matrix is protected by a seal made up of the eponychiam and cuticle. Again, we can visually see this, it is the small thin band that surrounds the base of our nails. The sides of our nails is protected by the paronychium, an overlapping layer of skin that is a common place for ingrowing toenails and hangnails.

Question 31

Label this

Answer 31

A - nail plate
B - lunula
C - eponcychium
D - proximal nail fold

Question 32

What is hair designed to do?

Answer 32

hair is designed to protect us from heat loss.

Question 33

What is hair made up from?

Answer 33

A single hair consists of the hair follicle, the hair growth factory if you like. It starts from the bulb which protects the hair papilla. The papilla contains capillaries that nourish cells in the hair follicle with oxygen and nutrients. The papilla is surrounded by hair matrix, similar to nail matrix it generates keratin which pushes forward older keratin cells, causing hair growth.

Question 34

What is the three stages of hair growth?

Answer 34

1. ** The Anagen phase** where the most active growing of hair happens > he hair matrix divide allows the hair to grow 0.5-1cm every 28 days
2. ** The Catagen phase ** - - this is where hair has a regression phase,
3. ** The Catagen phase ** his results from after the catagen phase, which is often referred to as the resting phase. This is the point where hair falls out or shreds,

Question 35

What is the hair growth cycle?

Answer 35

Question 36

What glands are their in the skin?

Answer 36

Eccrine and Apocrine glands
Ceruminous glands
Sebaceous glands

Question 37

What are the eccrine glands?

Answer 37

Eccrine or sweat glands are found through-out the skin except the ear canals, nail beds and labia.

They are found within the dermis of the skin and extend down to the subcutaneous tissue layer. It produces sweat, a solution made up of sodium chloride (salt), water, urea, uric acid, glucose, ammonia, lactic acid and enzymes. It’s major function is to reduce body heat in response to warm environments.

By secreting sweat, heat is then lost through evaporation, leading to reduce core temperature. It is why eccrine glands are found in bigger numbers on the forehead, as well as the palms of hands and soles of the feet. The eccrine glands has the ability to produce 1.8L of sweat per hour.

Question 38

What are the apocrine glands?

Answer 38

Apocrine glands are found under the arm pits (axilla), groin, ear canal, eye lids and around the nipples on breasts. These sweat glands lie deeper in the skin than eccrine glands. Whilst they produce sweat, they also produce an odourless lipid substance that when in contact with bacteria will omit an odour (what you and I would call body odour (BO)). This is the body’s cue to wash the skin and maintain hygiene.

Question 39

What are ceremonious glands in the skin?

Answer 39

These are modified apocrine glands that are found in the lining of the external ear. They help produce cerumen (or ear wax) that provides a protective but sticky layer to prevent any pathogens entering the ear canal. It is for this reason when we have an ear infection, we develop a waxy build up in our ears.

Question 40

What the sebaceous glands?

Answer 40

Sebaceous glands are found through-out the skin, except the palms of hands and the soles of the feet. Sebaceous glands release a substance called sebum, an oily lipid rich substance made up of proteins, salts, cholesterol and triglycerides. The purpose of sebum is to cover the hair shafts, protecting them being dry and brittle. Sebum also reduces the amount of water lost via evaporation, meaning it also helps with heat loss management.

Question 41

Label this

Answer 41

A - sebaceous glands
B - sweat glands
C - blood vessels
D - fat

Question 42

Where can you find the blood vessels in the skin?

Answer 42

In the dermis

Question 43

What are the two blood vessels networks in the skin?

Answer 43

The Superficial Vascular Plexus
The Deep Vascular Plexus

Question 44

What are the The Superficial Vascular plexus?

Answer 44

The superficial vascular plexus is a network of interconnecting arterioles and venules that can split off to capillary loops within the dermal ridges. These help supply oxygen and nutrients to the epidermis and dermis.

Question 45

What are the deep vascular plexus?

Answer 45

The deep vascular plexus is another network of interconnecting arterioles and venules that splits off to capillaries around the subcutaneous tissue layer, and other key structures within the dermis such as the glands and hair follicles.

Question 46

What role do the capillaries play in the epidermis?

Answer 46

Heat loss management

They can dilate and increase blood flow to encourage heat to be lost through the epidermis. Or the hypothalamus can trigger vasoconstriction of arterioles within the superficial vascular plexus to shunt away from the capillaries to prevent heat loss.

Question 47

What turns bruises yellow when healing?

Answer 47

The biliverdin is converted into bilirubin

Question 48

What is the subcutaneous layer?

Answer 48

Not part of the integumentary system, is the fat layer under the skin in which is made up of adipose tissue which stores triglycerides