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

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

SkinProtection, 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 –Keratinocytes –Melanocytes– Merkel cells– Langerhan cells and primary immune defence

• Describe the Basement Membrane

• Describe the Dermis– Briefly describe the Papillary & Reticular layers

• Explain the structure & function of skin hair, nails & glands

Healthy Skin

• Epidermis• Basement

membrane

• Dermis• Subcutaneous

tissue

Source- Porth 2011 LLW

Epidermis


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


THE EPIDERMIS

Epidermal cells produce:

•KERATIN- • fibrous protein•virtually water proof • Think about Hydrophobic and hydrophilic concepts

•MELANIN- •Pigment •protects against UV light


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, • Langerhan's cells, • Melanocytes and • Merkel cells.


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


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


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.


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

http://en.wikipedia.org/wiki/Langerhans_cell

The brown stains are Langherhan Cells that are present in infected skin

Infection Control & the Skin1. 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.



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.


Colour Transfer


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


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.


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


Dermis-PAPILLARY LAYER

Capillary blood flow

Nerve Fibres

papilla

Capillary Dilation to increase blood flow

Defence against!


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.


Pacinian corpuscle

• larger and fewer in number than both Merkel cells and Meissner's corpuscles

– detect deep pressure changes and vibrations from a distance

http://en.wikipedia.org/wiki/File:Gray935.png


http://upload.wikimedia.org/wikipedia/commons/5/52/Gray935.png

Ruffini Corpuscle

• Sensitive to skin stretch, and contributes to the control of finger position and movement

• located in the deep layers of the skin,


Distribution of nerve receptors


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


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


• 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- SebaceousOpens from the hair follicle Secretes oily substance

(mixes with bacteria on skin surface -)

How do you notice this?


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


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………………………………….


Date post:	29-Dec-2015
Category:	Documents
Upload:	marlene-parks
View:	216 times
Download:	3 times

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

Documents