Growth Renewal and Functions Skin Growth Renewal and Functions © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005

© Clinical Science Applied to Nursing /SONMS/Cardiff University/092005 Learning Outcomes Describe the strata of the epidermis: Briefly describe cell communication Re cell specification within the epidermis outline functions of Keratinocytes Melanocytes Merkel cells Langerhan cells Describe the basement membrane Describe the Dermis Briefly describe the papillary & reticular layers Explain the structure & function of skin hair, nails & glands © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005

© Clinical Science Applied to Nursing /SONMS/Cardiff University/092005 OVERVIEW of SKIN = DERM OUTSIDE SKIN = (Epi dermis) includes, hair, nails, glands. Nerves Touch & pain, receptors. INSIDE SKIN = (Dermis), includes, blood vessels, blood cells, muscle tissue. connective tissues © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005

© Clinical Science Applied to Nursing /SONMS/Cardiff University/092005 THE EPIDERMIS Epidermal cells produce: KERATIN- fibrous protein virtually water proof MELANIN- Pigment protects against UV light © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005

One cell divides to form 2 identical cells Mitosis = Cell division – One cell divides to form 2 identical cells from the Base Layer Cells change progressively in the epidermis Cell appearance changes as they migrate to the top Cells migrate to replace cells worn away SCRATCH YOUR SKIN WITH YOUR NAILS AND YOU WILL TAKE AWAYS THOUSANDS OF TOP CELLS THAT HAVE TO BE REPLACED © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005

© Clinical Science Applied to Nursing /SONMS/Cardiff University/092005 The base layer A single layer of cells (columnar or cuboidal) continually divide from a fixed position producing new cells i.e. Keratinocytes, Langerhan's cells, Melanocytes and Merkel cells. © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005

© Clinical Science Applied to Nursing /SONMS/Cardiff University/092005 The stratum spinosum - Highly interactive: Cell wall is constantly mobile, New cells differentiate (change) They also migrate toward the surface. The stratum spinosum contains: Keratinocytes, Langerhan's cells, Melanocytes © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005

© Clinical Science Applied to Nursing /SONMS/Cardiff University/092005 Stratum Granulosum Cells have changed form & function by this stage Some loose cytoplasm Some loose DNA, Others continue to synthesis keratin. The dying process starts © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005

© Clinical Science Applied to Nursing /SONMS/Cardiff University/092005 KERATIN Soft KERATIN-found in skin. Hard KERATIN found nails. Both protect living cells that lie beneath. © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005

© Clinical Science Applied to Nursing /SONMS/Cardiff University/092005 Keratinocytes- Building block of the Epidermis. Joined by the basement membrane & cell to cell by hemidesmones Produce KERATIN. immunologic tasks Example: Keratinocytes secrete Interleukin-1, & pass this to Langerhan cells in the skin © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005

Infection Control & the Skin Foreign particles enter Keratinized epidemis, particles stick to Langerhan's cells. Foreign body = antigen Langerhan cells offer antigen to white blood cells (lymphocytes) in the skin. Lymphocytes also receive interleukin-1 from Langerhan's cells and produce interleukin-2. Interleukin-2. binds to receptors on other lymphocytes to stimulate reproduction of many lymphocytes -this starts the fight against infection © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005

© Clinical Science Applied to Nursing /SONMS/Cardiff University/092005 The stratum corneum Dead keratinized multi-layered strata. Face approx 15 layers. Palms over 100 layers. Arms approx 25 layers. © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005

© Clinical Science Applied to Nursing /SONMS/Cardiff University/092005 Langerhan's cells Lie in the stratum spinosum. They are derived from Stem cells from the bone marrow. These cells also have dendrites - look much like tennis rackets © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005

© Clinical Science Applied to Nursing /SONMS/Cardiff University/092005 Melanocytes Synthesise pigment granules. PIGMENT GRANULES = MELANOSOMES - these contain melanin, (brown colour). Melanosomes are transferred to Keratinocytes through dendritic processes © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005

© Clinical Science Applied to Nursing /SONMS/Cardiff University/092005 MELANIN & Skin Colour Melanocytes - scattered throughout the base layer of the epidermis Melanocytes the same in most races- the amount of melanin produced by the cells determines skin colour. Genes, Sunlight, Hormones secreted by the pituitary gland control the amount of Melanin produced by Melanocytes. © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005

© Clinical Science Applied to Nursing /SONMS/Cardiff University/092005 Colour Transfer © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005

© Clinical Science Applied to Nursing /SONMS/Cardiff University/092005 Merkel Cells Free nerve endings attached to these epidermal cells. Found in the skin of the fingers, toes, lips, mouth and all touch areas. Their function is to detect touch. © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005

© Clinical Science Applied to Nursing /SONMS/Cardiff University/092005 Merkel cells © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005

Distribution of nerve receptors © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005

BASEMENT MEMBRANE ZONE Below the epidermis Anchoring complex joins epidermis to dermis. Anchoring complex is composed of hemidesmosomes: A ‘spot weld’ that holds cells together- Requires anchoring filaments, fibrils & glue. © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005

© Clinical Science Applied to Nursing /SONMS/Cardiff University/092005 The Filaments & ‘Glue’ Collagen fibres + Glycoproteins Elasticity Adhesion, strength anchorage. This also forms defence barrier Allows lymphocytes, neutrophils and langerhan's cells to penetrate Bars larger molecules e.g. most bacteria © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005

Dermis-PAPILLARY LAYER Defence against! papilla Capillary Dilation to increase blood flow Capillary blood flow Nerve Fibres © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005

© Clinical Science Applied to Nursing /SONMS/Cardiff University/092005 THE RETICULAR LAYER Tough - durable Random collagen fibres - this gives rise to the cleavage lines on the body and finger prints. Within this blood & lymph vessels nerve endings, fat, oils glands & hair roots © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005

Special Glands in the epidermis. SWEAT GLANDS -watery secretions – evaporates to cool the body SEBACEOUS GLANDS -oily sebum – protective: lubricates & prevents water loss- also thought to have an antibacterial function © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005

© Clinical Science Applied to Nursing /SONMS/Cardiff University/092005 Glands ECCRINE- Sweat Transports sweat to regulate body temperature APOCRINE- Sebaceous Opens from the hair follicle Secretes oily substance (mixes with bacteria on skin surface -) How do you notice this? © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005

© Clinical Science Applied to Nursing /SONMS/Cardiff University/092005 Skin Structures HAIR requires a hair follicle & muscle to move. NAILS- a Hardened keratinized plate Sebaceous glands lubricate the hair (the muscle under the sebaceous gland, attached to the hair, also allows for thermoregulation. Apocrine glands (axilla/groin) lubricates Skin and gives off an odour © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005

© Clinical Science Applied to Nursing /SONMS/Cardiff University/092005 Recap Several important layers & cells A basement glue and cell to cell connection points Specialised cells for special functions: Immune response……………………….……… Water proofing…………………………………… Protection from UV light……………………….…. Thermoregulation………………………………… Excretion……………………………………………. Sensory perception…………………………………. © Clinical Science Applied to Nursing /SONMS/Cardiff University/092005