anatomy and physiology of the skin, layer of the skin, function of the skin, physiology of the skin, nursing assessment, physical assessment

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SUBJECT – MEDICAL & SURGICAL NURSING
TOPIC – INTEGUMENTARY SYSTEM
PREPARED BY DOLISHA WARBI

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ANATOMY AND PHYSIOLOGY OF SKIN:
q The skin is also known as cutaneous membrane or in tegument, covers the external surface of the body.
q It is a sensory organ which is an largest organ of the body in both surface area and weight.
q Integumentary system is composed of skin, hair, nails, glands pH - 4 to 5.6.
q As we age our skin changes.

3. LAYERS OF THE SKIN:
1. Epidermis: The outermost layer of the skin, primarily composed of epithelial cells. It provides a protective barrier
against pathogens, UV radiation, and water loss. The epidermis also contains melanocytes, which produce melanin,
the pigment responsible for skin color.
2. Dermis: The middle layer of the skin, composed of connective tissue, blood vessels, nerve endings, and appendages
such as hair follicles and sweat glands. The dermis provides structural support and elasticity to the skin.
3. Hypodermis (Subcutaneous Tissue): The innermost layer of the skin, consisting of adipose tissue and connective
tissue. It serves as insulation, energy storage, and cushioning for the body.
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4. FIVE SUBLAYERS OF THE EPIDERMIS
The epidermis is actually made up of a collection of 4-5 sublayers, which include (from the lowest part to the
outermost layer of the epidermis):
STRATUM BASALE:
• Stratum Basale is the deepest layer of the epidermis and is made up of a single layer of cells, with the main proportion
being basal cells.
• This layers rests on top of a thin protein layer known as the basement membrane, which forms the "floor" of the
epidermis, connecting stratum Basale and the epidermis with the dermis.
• Basal cells are responsible for producing a type of cell known as keratinocytes.
• Keratinocytes are cells that produce lipids which function as a protective barrier for skin, as well as keratin—a structural
and protective protein that makes up skin, hair, and nails.
• They're also important for the formation of Vitamin D when exposed to the sun.
STRATUM SPINOSUM:
• Stratum spinosum is the sublayer positioned right on top of stratum basale, and is 8-10 cell layers thick. It comprises most
of the epidermis.
• The keratinocytes in this sublayer are irregularly shaped and joined together with desmosomes—protein complexes that
provide strong adhesion between cells.
• Desmosomes play a role in maintaining the structural integrity of skin.
• Langerhans cells are in abundance in the stratum spinosum, scattered amongst the keratinocytes. They act as first line
defenders, protecting against pathogenic microorganisms and damaged cells.
• In this layer, keratinocytes start to produce keratin and create a barrier to prevent water loss.
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5. STRATUM GRANULOSUM:
• Stratum granulosum is a thin layer that contains keratinocytes—which are specifically known as granular cells in this layer (hence
the name, granulosum).
• Skin cells in this layer start to die in order to form a tough waterproof barrier on the surface of the skin, in a process known as
keratinization.
• Granular cells bind these dead cells together, forming a protective barrier from the body and the outside world.
STRATUM LUCIDUM:
• Stratum lucidum is a thin layer that gives skin the ability to stretch, and also contains a keratin precursor which causes the
degeneration of skin cells.
• This layer lessens the effects of friction in the skin, and It's only found in thick areas of the body like the palms and soles of the feet.
STRATUM CORNEUM:
• Stratum corneum is probably the most famous of the 5 sublayers, due to its effects on overall skin health.
• It's the outermost sublayer of skin, and comprised of dead cells contained in a lipid matrix. Once thought to be nothing more than a
layer of dead cells, It's now known that it serves critical biological functions for the skin.
• Here, keratinocytes are turned into corneocytes—dying and dead cells which make up the majority of the stratum corneum.
• Lipid bilayers comprised of cholesterol, ceramides, and fatty acids surround the corneocytes, where they form a tough brick-and-
mortar structure.
• This is why the stratum corneum is sometimes referred to as a brick wall, as it functions to provide a tough barrier from the outside
world, and protect the deeper layers of skin from pathogenic invasion and water loss.
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6. DESQUAMATION IN THE STRATUM CORNEUM:
• On the surface of the stratum corneum, the final act of keratinization occurs known as desquamation, where
corneocytes shed, or exfoliate, off of the skin.
• Once keratinocytes are changed into corneocytes, they shed within about a 2-week period. As this happens, they're
continuously replaced by newly formed corneocytes from deeper epidermal layers.
• Desquamation is an important natural cycle of renewal for the skin, which keeps it in good condition.
(dust found in homes is mainly just dead skin cells)
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7. FUNCTIONS OF THE SKIN:
1. Protection: The skin acts as a physical barrier, protecting the body from pathogens, chemicals, and physical injury.
It also prevents excessive water loss and regulates temperature.
2. Sensation: Nerve endings in the skin detect touch, pressure, temperature, and pain, allowing us to interact with the
environment and respond to stimuli.
3. Thermoregulation: Blood vessels in the skin help regulate body temperature by dilating to release heat or
constricting to conserve heat. Sweat glands also play a role in cooling the body through evaporation.
4. Excretion: Sweat glands excrete waste products such as water, electrolytes, and small amounts of metabolic waste
through perspiration.
5. Immunity: Specialized cells in the skin, such as Langerhans cells, play a role in the body's immune response by
identifying and destroying pathogens that penetrate the skin.
6. Synthesis of Vitamin D: Sunlight stimulates the production of vitamin D in the skin, which is essential for calcium
absorption and bone health.
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8. PHYSIOLOGY OF THE SKIN:
1. Cell Turnover: The epidermis undergoes constant renewal through a process called keratinization, where new cells
are produced in the basal layer and gradually move toward the surface, replacing old cells that are shed from the
skin's surface.
2. Blood Circulation: Blood vessels in the dermis deliver oxygen and nutrients to the skin cells while removing waste
products. Changes in blood flow can affect skin color and temperature.
3. Glandular Secretions: Sweat glands produce sweat, which helps regulate body temperature and excrete waste
products. Sebaceous glands secrete sebum, an oily substance that moisturizes and protects the skin and hair.
4. Hair Growth: Hair follicles in the dermis produce hair, which serves various functions such as insulation,
protection, and sensory perception.
Appendages of skin:
• Hair follicle and Hair • Sweat and sebaceous glands • Nails on fingers and toes:
• Hair is composed primarily of keratin. The dead keratinocytes fuse together to form the hair. Follicle/bulb, which
contains cells that give rise to the keratinocytes that make up the hair, as well as blood vessels that nourish the
growing.
• The color of hair is due to melanin. Dark hair contains true melanin like that found in the skin. Blond and red hair
result from types of melanin that contain sulfur and iron. Hair goes gray when melanocytes age and lose the enzyme
necessary to produce melanin. White hair occurs when air bubbles become incorporated into the growing hair.
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9. Sweat and Sebaceous Gland - An adult human has between 1.6 to 4 million sudoriferous glands, or sweat glands.
Most are of a type known as eccrine sweat glands, which are found almost all over the surface of the body and are
most numerous on the palms and soles. Eccrine sweat glands begin deep in the dermis and connect to the surface of the
skin by a coiled duct.
• In addition, nerve fibers that encircle the sweat glands stimulate the glands in response to fear, excitement, or
anxiety.
Nails on fingers and toes - Nails on the fingers and toes are made of hard, keratin- filled epidermal cells. They protect
the ends of the digits from injury, help us grasp small objects, and enable us to scratch.
• The part of the nail that is visible is called the nail body or nail plate, and the portion of the nail body that extends
past the end of the digit is called the free edge. The nail groove is the fold on the side and the eponychium is the skin
that holds the nail root.
• Most of the nail body appears pink because of blood flowing in the tissue underneath. The pale, semicircular area
called the lunula appears white due to an underlying thick layer of epidermis that does not contain blood vessels.
• The part of the nail that is buried under the skin is called the root. Nails grow as epidermal cells below the nail root
and transform into hard nail cells that accumulate at the base of the nail, pushing the rest of the nail forward.
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10. NURSING ASSESSMENT:
HISTORY COLLECTION
Ask about:
• Initial and subsequent morphology and location(s) of lesions
• Symptoms (eg, itch, pain, tenderness, burning)
• Date of onset and duration
• Severity and factors causing flares
• Medications (including over-the-counter products) used for treatment and response to treatment
• History of previous similar problem.
Additional questions should be asked involved:
qChanges in size and appearance of the lesion.
qHistory of spontaneous or trauma-induced bleeding in the lesion.
qHistory of sunburns or tanning bed use.
qHistory of sunscreen use.
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11. PHYSICAL ASSESSMENT:
INSPECTION/OBSERVATION:
1) Colour of the skin – Pallor / Jaundice / cyanosis / flushing etc.
2) Rashes - Redness / Itchy patches.
3) Bruising/ Wound/pressure injuries - red, blue, or purplish patches
4) Boney prominence – Intact/Rupture Blister/Tissue loss.
5) Equipment site – Changes in color/swollen/present of discharge.
6) Pressure injuries underlying tissue - Redness, warmth, induration (hardness), swelling, and signs of
infection.
7) Navy/moles – Raised/Flat ,Sudden enlargement/irregular border of mold.
8) Condition of hair - Hair shedding (telogen or anagen effluvium) baldness (alopecia) excess hair (hirsutism)
9) Scalp – Cleanliness, condition of hair, dandruff, pediculi, infection like ringworm.
10) Lesion: Coloring - Red, yellow, brown, black, green.
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12. PALPATION:
1) Skin temperature – Warm/Cold/Clammy.
2) Moisture – Dry/Flaky.
3) Turgor – Mobility/Tents/Lose.
4) Edema - Present/Absent of Pitting edema.
5) Deformities: Present/Absent (if present mention).
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