Dramatic Contexts
By Kate Garrett
Skin Basics.
Structure.
The skin has three main distinct layers: the epidermis, the dermis and the subcutaneous layers. Between these layers is a specialised layer which acts like a 'glue', sticking the layers together; this is the basement membrane.
The Epidermis.
This is the outer layer of the skin and within it there are 5 layers:
Stratum Corneum (Horny Layer)
This is the outer layer and is made up of flat dead skin cells which have moved from the germinating layer, cells are constantly shredding this process is known as desquamation.
Stratum Lucidium (Clear Layer)
This layer is made up of transparent dead cells filled with keratin that are in 3/4 rows. As these cells have gone through mitosis they have nuclei. The tickness of this layer depends on where it is on the body for example this layer is a lot thinner on the face but thick on the soles or palms of the hands, it is generally absent in hair skin.
Stratum Granulosum (Granular Layer)
This layer is made up of distinct cells shapes that each contain grandles thats job it is to hardden the cells; this process is called keratinisation. It allows the dead cells to link to the living below.
Stratum Spinosum (Prickle Cell Layer)
This is known as the Prickle cell layer becasue each of the rounded cells contained within it has short projections that make contact with the neighbouring cells and give them a prickly appearance. The living cells of this layer are capable of divinding by the process of mistosis.
Stratum Germativum (Basal Cell Layer)
It consists of a single layer of column cells on a basement membrane this is the layer that seperates the epidermis from the dermis by a single layer of column cells on the basement membrane (the 'glue'). Reproduction of the epridermal cells happens they stay in the layer for around 6 weeks before moving up to the stratum corneum (horny layer) for shredding. During the reproducing and dividing of the cells there are star shaped cells that are called melanocytes, which make the pigment melanin which is the main source for the colour of the skin.
(Le Quesne, 2005, p26)
The Dermis.
This is the inside layer of the skin which is made up of dense connective tissue which is alot thicker and sits under the edpidermis. Sometimes this is referred to as the 'real' skin as it contains other structures such as nerve ending, blood vessels, etc. This layers function is to provide support and strength. This has two layers:
The Papillary Layer
This is made up of fatty connective tissue that is connected to the epidermis by little cone shaped projections (papillae) which contain blood capillaries and nerve endings. This also supplies nutriton to the upper layer.
The Reticular Layer
This layer contains many protien fibres which allows the skin to expand, contract and other movements. The three proteins are:
Yellow Elastine Fibres - for elastity in the skin
White Collagen Fibres- for strength
Reticular Fibres - give support to hold all these structures in place
These firbres are made by specialist cells (fibreblasts) and live in ground substance, a gel.
(Le Quesne, 2005, p26 &25)
The Subcutaneous Tissue.
This is the fatty layer of skin which is caused by lipocytes producing lipids (the fat cells). This layers function is to protect the muscles, bones, organs, etc from getting damaged, it also acts as an insulation layer ans is a source of engery if the body needs it.
Other parts that make up the skin.
Blood Vessels
- Arteries carry nutrients & oxygen via capillaries
- Veins remove waste
- Capillaries help heat regulation
Nerves
- Nerve ending are found in both the dermis and subcutaneous
- Responding to pain, pressure, temprature and touch
- Carrying messages to the brain and awaiting responses
Arector Pili Muscles
- Are within muscle tissue and connected to the hair follicle
- Raises the hair follicle to close the pore
Sebaceous Glands
- Sit adjacent to hair follicles
- Produces sebum
What is Sebum?
Its function is to lubricate the skin and hair, and when it mixes with sweat it forms acid mantle which is a way of waterproofing the skin.
Hair
- Roots are in the follical grow through the dermis and epidermis
- Linked to body temprature and gender characteristics
- Isnt present on soles, palms or lips
Hair Follicle
- Produce the hair and provide nutrition to the hair
Sweat Glands
- Also known as eccrine glands
- Found all over the body
- Produce sweat, water and Urea and remove toxins
Apocrine Glands
- These are bigger than the sweat glands
- Only found in hairy parts of the body (armpits, nipples, genitals)
- They are part of the nervous system, responding to sexual attraction and emotions
Urea.
Urea is a natural moisturiser found in our skin (the stratum corneum layer)
The human skin is an organ - the largest of the body. It provides a tough, flexiable covering, with many important functions.(Le Quesne, 2005, p24)
Firgure 1.1
Below shows the structure of the skin for thick and hairless skin (such as on your palms and heels of the feet) and thin and hairy skin (such as on the arms) as you can see the subcutaneous layer is alot thicker on the thicker skin as this fatty layer provides padding as on your soles of your feet you are contantly appling pressure so this cushions the skin making the skin tougher and less likey to spilt the skin. Where as the thinner hair has a dense amount of hair as tghis is to help regulate body temprature among other things.
Body Temprature is controlled by the blood vessels constricting or dilating to move the blood flow depending wetaher heat needs to be retained or reduced.
Skin Functions.
Sensations such as heat/cold/pressure/touch is felt by the nerve endings in our skin.
Protection of the internal organs for injury, chemicals and sun damage.
Prevents loss of nutrition.
Excretion of salt and urea via sweat.
Absorbation of some substances such as body creams and medication.
Appearance - the appearance of the skin can tell you alot about the person whether they are healthy or not, about their lifestyle, their age, etc.
Figure 1.2
Skin types.
The 4 basic types:
Normal - this is a balance between dry and oily
- skin texture is even all over witha a healthy look, well pigmented and no blemishes
- Firm with good elasticity
Dry - this is where oils and moisture is lacking
- small pores, corse/thin skin texture
- may be flaky or sensitive
- commonly ageing lines appear earlier than normal
- pigmentation may sometimes be uneven making freckles
Oily - this is where excess sebum is produced, this causes blemishes and a shiny appearance
- larger pores
- corse but thick skin
- may appear sallow due to th edead skin cells being embedded into the excess sebum
- uneven pigmentation is common
- skin disorders such as; comedones, papules and sebaceoud cyts are common
Combination - this is where there are a mix f skin types on the face, the most common is the oily T zone and dry skin around the nose/mouth
Other characteristics.
Sensitive - dry skin is most often very sensitive whether to the touch or by products.
- flushed look to the face
Dehydrated- moisture is lacking, flaking, superficial lines and broken cappilliares may appear
- this can be apparant in any skin type however it is mostly found in dry and combination
Mature skin - this skin looks different from younger skin as discussed ageing - what happens?
Skin is the thing we see when we look at someone and it tells you alot about who they are, so I have chosen to look into detail as much as I can about skin to find out what it actually is, the functions and are there different types, understanding the basics will allow me to undertand the ageing process of it properly. I have then disscussed what changes in the skin, underneath and how if affect appeareance on the tabs (ageing -what happens? and ageing -appearance). With all my information collected I will use it to inform my design/sculpt.