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45 Cards in this Set
- Front
- Back
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What is the epidermis? |
The epidermis is the layer of skin that we can see. It varies in thickness. The cells on the surface are constantly coming off and are replaced by cells from below. There are 5 layers in the epidermis. |
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Name th 5 layers of the epidermis |
1. Stratum corneum - surface 2. Stratum lucidum - clear layer 3. Stratum granulosum - granular layer 4. Stratum spinosum - prickle cell layer 5. Stratum germinativum - basal layer |
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Definition of the dermis |
Commonly known as the true skin. This layer is connected to the blood and lymph supply as well as the nerves and contains sweat and sebaceous glands, hair follicles and many living cells. It is made of connective tissue (mainly areolar tissue which is tough and elastic and contains white collagen fibres and yellow elastic tissue (elastin). |
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Function of Collagen |
Plumps the skin |
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Function of Elastin |
Keeps skin supple and elastic |
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Name the main structures of the dermis |
1. Specialised cells 2. Nerve endings 3. Sweat glands 4. Hair follicles 5. Sebaceous glands 6. Blood suply 7. Lumphatic capillary 8. Papilla |
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What are the functions of the skin? |
SHAPES Very Much 1. Secretion 2. Heat Regulation 3. Absorption 4. Protection 5. Elimination 6. Sensation 7. Vitamin D Formation 8. Melanin Formation |
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What does 'congenital' mean? |
'from birth' |
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Name two congenital skin pathologies |
Eczema and Psoriasis |
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Name 6 bacterial skin pathologies |
Acne rosacea Acne vulgaris Boils Carbuncles Folliculitis Impetigo (Contagious) |
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Name 4 viral skin pathologies |
Warts Verrucas Herpes simplex Herpes zoster (All contagious) |
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Name a fungal skin pathology |
Tinea corporis, pedis (infectious) |
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Name 2 parasitic infestations |
Pediculosis Scabies (contagious) |
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Name 10 pigmentation disorders |
Dermatosis Papulosa Nigra Papilloma Vitiligo Albinism Chloasma Ephelides Lentigo Moles (papilloma) Naevae Port wine stains |
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Descripe the stratum corneum |
The stratum corneum is the surface of the skin. hardened, flattened dead cells constantly being shed - desquamation cell membrane is not visible |
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Describe the stratum lucidum |
This is the clear layer of the skin denucleated cells but not completely hard most easily visible under a microscope (only on palms and soles) cell membrane becomes less visible |
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Describe the stratum granulosum |
This is the granular layer of the skin. cells have a distinct nucleus but cell membranes are dying contains granules which are visible in healing tissue after trauma stadium at which keratin enters the cell |
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Describe the stratum spinosum |
This is the prickle cell layer of the skin cells are living and membranes are intact, they have fibrils which interlock capable of mitosis under friction or pressure, i.e. on soles of feet or pals of hands. |
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Describe the stratum germinativum |
This is the basal layer of the skin Primary site of cell division/reproduction in the skin cells are living this layer contains melanin |
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What are melanocytes? |
Melanocytes are cells that produce Melanin. |
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What can be found in the specialised cells of the skin? |
Fibroblasts Mast cells Histiocytes Leukocytes |
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Function of nerve endings |
alert the braind/body to heat, cold, pressure, pain part of the defence system of the body |
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Describe the sweat glands |
Stretch from deep in the dermis to the outer layer of the epidermis. Contains mainly water and salts (mostly sodium chloride) Is produced by eccrine and apocrine glands |
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Describe the eccrine glands |
Excrete watery sweat Control body temperature Found all over the body (esp. in palms of hands and soles of feet) |
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Describe the apocrine glands |
Found in the groin and axillae (armpits) Excrete a milky fluid which, when it mixes with bacteria on the surface of the skin, produces body odour. |
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Describe the hair follicles |
Travel through the epidermis and dermis Erector pili (a tiny muscle) are attached to each hair to help with temperature control |
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Describe the sebaceous glands |
Connected with hair follicles Produce sebum Found in hairy areas Sweat and sebum form an acid mantle which controls bacteria levels, prevents infections and disease and acts as a moisturiser. |
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What is sebum? |
A fatty acid which keeps the skin moist and which lubricates the hair shaft. |
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What is the ph balance of the skin |
4.5 - 5.6 (acid) helps to prevent bacterial growth |
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Describe the function of the lymphatic capillary |
To carry waste products away from the area. Works in conjunction with blood supply. |
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What are papilla? |
Small conical projections at the base of the hair They contain blood vessels and nerves (nutrient supply for the hair) |
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What is the body temperature of a healthy person? |
Ca. 37 Degrees Celcius |
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What organs are involved in heat regulation? |
Muscles Liver Digestive Organs |
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Describe heat regulation in the body |
Heat regulation is controlled by vasodilation and vasoconstriction. |
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Describe vasodilation |
The capillaries dilate, allowing more blood to reach the surface of the skin. The pores dilate allowing the heat to be lost from the body. Flushing of skin - or hyperaemia - follows. Sweating will occur simultaneously. The evaporation of perspiration from the surface has a cooling effect on the body. |
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Describe vasoconstriction |
When cold, the body protects itself by moving blood from the extremities to the major organs to ensure they are being kept warm. The capillaries contract as do the pores. As a result the skin appears pale and heat loss is inhibited. The erector pili muscles contract. Shivering occurs, caused by rapid and repeated muscle contractions. |
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Describe the absorption function of the skin |
The skin is waterproof but some drugs and essential oils can penetrate through the layers, hair follicles and sweat glands. The amount of penetration is affected by the health and condition of the skin. |
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Describe the protection function of the skin |
The acid mantle forms a protective layer on the skin against micro-organisms. Melanin protects against ultraviolet light damage to tissuses. Sensory nerve endings warn of possible trauma and, by reflex action, prevent greater damage to the body. |
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Describe the elimination function of the skin |
Toxins normally take the form of waste salts and water and are eliminated from the body through the skin via the sweat glands. |
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Describe the sensation function of the skin |
Nerve endings in the dermis make the body aware of its surroundings They warn of pain, cold, pressure and touch to help prevent trauma to the skin and underlying structures. Different receptors lie at different levels in the skin. Pain and Touch receptors are closer to the surface. |
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Describe Vitamin D formation |
Vitamin D is needed for the formation and maintenance of bone. Vit D production is stimulated by ultraviolet light which converts 7-dehydro-cholesterol in the sebum into Vit. D. This circulates in the blood and any excess is stored in the liver. |
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What can be caused by the lack of Vit. D? |
Rickets in children |
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Name the crucial two components in Vit D production |
Ultraviolet light and 7-dehydro-cholesterol (found in sebum) |
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Describe Melanin formation |
In the sun, the hormone MSH stimulates the melanocytes in the basal layer of the epidermis to produce melanin. |
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What is the function of Melanin |
It produces a darkening of the skin to protect the underlying structures of the skin. The pigment protects the body from harmful effects of the sun's rays since dark colours absorb radiation. |
