© Clinical Science Applied to Nursing /SONMS/Cardiff University/ Skin Introduction

Learning Outcomes List the layers of the skin List the layers of the skin List the functions of the skin List the functions of the skin Briefly describe the layers of the epidermis Briefly describe the layers of the epidermis Outline the functions of: Outline the functions of: Keratinocytes Keratinocytes Melanocytes Melanocytes Langerhan cells Langerhan cells Merkel cells Merkel cells Briefly describe the Dermis Briefly describe the Dermis Distinguish between the papillary & reticular layers of the dermis Distinguish between the papillary & reticular layers of the dermis Briefly explain the structure & function of hair, nails & glands Briefly explain the structure & function of hair, nails & glands

© Clinical Science Applied to Nursing /SONMS/Cardiff University/ OVERVIEW of SKIN Epidermis Epidermis Dermis Dermis Subcutaneous Layer Subcutaneous Layer ( network of fat and collagen cells, functions as an insulator)

© Clinical Science Applied to Nursing /SONMS/Cardiff University/ General Functions of the skin Protective barrier against pathogens Protective barrier against pathogens Helps regulate temperature Helps regulate temperature Gathers sensory information from the environment Gathers sensory information from the environment Synthesis of Vitamin D Synthesis of Vitamin D Aesthetics and communication Aesthetics and communication Excretion (minor function) Excretion (minor function)

© Clinical Science Applied to Nursing /SONMS/Cardiff University/ THE EPIDERMIS The epidermis is composed of Layers (or Strata) (see left side labels of diagram) Epidermal cells include: KeratinocytesMelanocytes Langerhans cells Merkel cells

© Clinical Science Applied to Nursing /SONMS/Cardiff University/ Cells in the Epidermis In the epidermis, cells: * are very interactive * produce protein * differentiate ( change as they progress to the surface ) * start to die towards the surface * are worn away at the surface [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/ Stratum Basale * Innermost layer * A single layer of basal cells Cells continually divide Cells continually divide (by Mitosis) to form the (by Mitosis) to form the Epidermal cells Epidermal cells

© Clinical Science Applied to Nursing /SONMS/Cardiff University/ Stratum Spinosum (‘spiny’ layer) Also known as the squamous cell layer Also known as the squamous cell layer Thickest layer of the epidermis Thickest layer of the epidermis This layer contains: This layer contains: Keratinocytes – produce keratinKeratinocytes – produce keratin Langerhan's cells - involved in immunityLangerhan's cells - involved in immunity Melanocytes – produce melaninMelanocytes – produce melanin

© Clinical Science Applied to Nursing /SONMS/Cardiff University/ Stratum Granulosum / Stratum Lucidum Cells have changed form & function Cells have changed form & function Some lose cytoplasm / DNA (others continue to synthesis keratin) Some lose cytoplasm / DNA (others continue to synthesis keratin) Cells get flatter and adhere together Cells get flatter and adhere together The dying process starts The dying process starts

© Clinical Science Applied to Nursing /SONMS/Cardiff University/ The stratum corneum Outermost layer of epidermis Dead keratinized multi-layered strata [More wear and tear  More layers] Dead cells are continuously shed Shedding process slows with age Complete cell turnover: 28 – 30 days in young adults 45 – 50 days in elderly adults

© Clinical Science Applied to Nursing /SONMS/Cardiff University/ Keratinocytes Building blocks of the Epidermis. Building blocks of the Epidermis. Joined to the basement membrane & cell to cell by Hemidesmosomes (an anchoring complex)Joined to the basement membrane & cell to cell by Hemidesmosomes (an anchoring complex) Produce KERATIN (fibrous protein that water proofs the skin)Produce KERATIN (fibrous protein that water proofs the skin) Involved in Immunity Involved in Immunity

© Clinical Science Applied to Nursing /SONMS/Cardiff University/ KERATIN Soft KERATIN- found in skin. Hard KERATIN found nails. Function: protection

© Clinical Science Applied to Nursing /SONMS/Cardiff University/ Melanocytes Synthesize pigment granules Synthesize pigment granules  Pigment Granules = MELANOSOMES - these contain melanin, (brown pigment for UV protection).  Melanosomes are transferred to Keratinocytes through dendritic processes

© Clinical Science Applied to Nursing /SONMS/Cardiff University/ MELANIN & Skin Colour Melanocytes - scattered throughout the base layer of the epidermis The amount of melanin produced by the cells determines skin colour Amount of Melanin affected by: Genes, Sunlight, Hormones

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

© Clinical Science Applied to Nursing /SONMS/Cardiff University/ Infection Control & the Skin Infection control involves: Langerhans cells (attach themselves to antigens that invade damaged skin and alert the immune system to their presence) (Langerhans cells originate from the Bone Marrow) Lymphocytes Interleukin 1  Interleukin 2

© Clinical Science Applied to Nursing /SONMS/Cardiff University/ Merkel Cells Tactile cells found all touch areas Tactile cells found all touch areas Their function is to detect touch Their function is to detect touch

© Clinical Science Applied to Nursing /SONMS/Cardiff University/ The Dermis Located under the epidermis Located under the epidermis Thickest layer of the skin Thickest layer of the skin Contains blood vessels, lymph vessels, hair follicles, sweat glands, sebaceous glands, nerve endings, collagen and elastin Contains blood vessels, lymph vessels, hair follicles, sweat glands, sebaceous glands, nerve endings, collagen and elastin Made up of two sublayers: Made up of two sublayers: Papillary layer (upper)Papillary layer (upper) Reticular layer (lower)Reticular layer (lower)

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

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

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

© Clinical Science Applied to Nursing /SONMS/Cardiff University/ 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/ Skin Structures HAIR HAIR requires a hair follicle & muscle to moverequires a hair follicle & muscle to move NAILS NAILS a Hardened keratinized platea Hardened keratinized plate Sebaceous glands Sebaceous glands lubricate the hairlubricate the hair Apocrine glands (axilla/groin) Apocrine glands (axilla/groin) give off an odourgive off an odour