© Clinical Science & Skill Applied to Nursing /SONMS/Cardiff University Skin Protection, Growth Renewal and Functions

© Clinical Science Applied to Nursing /SONMS/Cardiff University Learning Outcomes Describe the strata of the epidermis: Briefly describe –cell communication –cell specification within the epidermis outline functions of –K eratinocytes –M elanocytes – M erkel cells – L angerhan cells and primary immune defence Describe the B asement M embrane Describe the Dermis –Briefly describe the P apillary & R eticular layers Explain the structure & function of skin hair, nails & glands

Healthy Skin Epidermis Basement membrane Dermis Subcutaneous tissue Source- Porth 2011 LLW Epidermis

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

© Clinical Science & Skill Applied to Nursing /SONMS/Cardiff University 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

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

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

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 & Skill Applied to Nursing /SONMS/Cardiff University

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

Keratinocytes- The Building block of the Epidermis. –Joined by the basement membrane & cell to cell by hemidesmones They Produce KERATIN. Keratinocytes- Immunologic function –They secrete Interleukin-1 (a ‘cell signal substance’) –They pass this to Langerhan cells in the skin when microbes (antigens) invade the skin. © Clinical Science & Skill Applied to Nursing /SONMS/Cardiff University

Langerhan's cells Inhabit the Stratum Spinosum. They are derived from Stem cells within the bone marrow. These cells also have dendrites - look much like tennis rackets (i.e. A body with a dendrite poking out The brown stains are Langherhan Cells that are present in infected skin

Infection Control & the Skin 1. Foreign particles enter the Keratinized Epidermis, 2. Keratinocytes may signal the Langerhan cell and other immune cells (interleukin 1 is a signal) 3. Signal and foreign particles stick to Langerhan's cells. Foreign body = antigen 4. Langerhan cells offer the antigen to white blood cells (lymphocytes) in the skin. 5. Lymphocytes also receive interleukin-1 from Langerhan's cells and Keratinocytes and produce interleukin-2 (another cell signal). 6. Interleukin-2. binds to receptors on other lymphocytes to stimulate reproduction of many more lymphocytes -this starts the fight against wider infection. © Clinical Science & Skill Applied to Nursing /SONMS/Cardiff University

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

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

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

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 & Skill Applied to Nursing /SONMS/Cardiff University

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

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

The Filaments & ‘Glue’ Collagen fibres + Glycoproteins ElasticityAdhesion, 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 & Skill Applied to Nursing /SONMS/Cardiff University

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

Meissner's corpuscle Because of their location in the dermis, these are particularly sensitive to touch vibrations These are limited in their detection because they can only signal that something is touching the skin. © Clinical Science & Skill Applied to Nursing /SONMS/Cardiff University

Pacinian corpuscle larger and fewer in number than both Merkel cells and Meissner's corpuscles – detect deep pressure changes and vibrations from a distance png © Clinical Science & Skill Applied to Nursing /SONMS/Cardiff University

Ruffini Corpuscle Sensitive to skin stretch, and contributes to the control of finger position and movement located in the deep layers of the skin, © Clinical Science & Skill Applied to Nursing /SONMS/Cardiff University

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

THE RETICULAR LAYER Tough - durable  Random collagen fibres - this gives rise to the cleavage lines on the body and finger prints - 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 & Skill Applied to Nursing /SONMS/Cardiff University

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

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 & Skill Applied to Nursing /SONMS/Cardiff University

Sweat glands –Apocrine –Eccrine Sebaceous glands Other appendages Hair Nails Source- Porth 2011 LLW Epidermis Sweat and Oil Glands Sweat gland

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 & Skill Applied to Nursing /SONMS/Cardiff University

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 & Skill Applied to Nursing /SONMS/Cardiff University

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 & Skill Applied to Nursing /SONMS/Cardiff University