2.2 Describe the aspects of the anatomy and physiology of the skin which inform the application of dressings

This guide will help you answer 2.2 Describe the aspects of the anatomy and physiology of the skin which inform the application of dressings.

The skin is the largest organ in the human body. It provides several layers of protection, helps with temperature regulation, and prevents harmful substances and microorganisms from entering the body. Understanding the skin’s structure and functions helps care workers to apply dressings safely and effectively.

The Three Main Layers

The skin is made up of three main layers:

Epidermis: The outermost layer.
Dermis: The middle supporting layer.
Subcutaneous tissue (Hypodermis): The innermost layer.

The Epidermis

The epidermis is the thin, outermost layer. It acts as the first defence. This layer contains:

Keratinocytes, which produce keratin, making the skin tough and water-resistant.
Melanocytes, which produce melanin, protecting against damage from ultraviolet light.

The epidermis has no blood vessels. It relies on the deeper dermis for nutrients. This layer regenerates often, which helps wounds heal.

The Dermis

The dermis sits beneath the epidermis. It is thicker and contains:

Blood vessels: Bring nutrients and remove waste.
Nerve endings: Allow us to sense pain, pressure, and temperature.
Hair follicles.
Sweat glands.
Sebaceous (oil) glands.
Collagen and elastin fibres, which provide strength and flexibility.

The rich blood supply supports healing by bringing white blood cells and nutrients to injuries.

The Subcutaneous Tissue

This is the deepest layer of skin. It consists of fat and connective tissue. It helps conserve heat, stores energy, and protects the muscles and bones underneath from injury.

Skin Functions Influencing Dressing Choice

Each skin layer has unique roles that relate directly to wound care and the selection of dressings.

Barrier Protection

The skin acts as a protective barrier. It stops germs and chemicals from getting in, and prevents too much water from escaping the body. If the epidermis is broken or thin, wounds are more at risk of infection and water loss.

Different dressings can help restore the barrier, keep wounds covered, and prevent harmful bacteria from entering.

Sensation

The dermis contains nerves that sense pain, touch, pressure, and temperature. When applying a dressing, it is important to:

Avoid painful application and removal.
Prevent further injury to the skin and underlying tissues.

Choosing soft, flexible dressings may help reduce pain during dressing changes.

Temperature Regulation

Sweat glands in the dermis help cool the body, and blood vessels widen or narrow to control heat loss. Some dressings can affect this process by creating a warm or insulated environment, speeding up healing or helping reduce infection risk. Overly thick or tight dressings may stop wounds from “breathing” and cause moisture build-up or over-heating.

Healing and Regeneration

The skin can repair itself. The epidermal cells migrate across wounds to close them. The dermis supplies blood, nutrients, and cells that fight infection and support new tissue growth. Dressings can:

Encourage new cell growth.
Keep the area moist, which speeds up cell movement.
Absorb wound fluid that would delay healing.

Skin Types and Conditions

Different types and conditions of skin affect how wounds heal and what dressings to use.

Thin or Elderly Skin

In older people or those with certain conditions, the skin becomes thinner and more fragile. The epidermis and dermis lose some of their structure and strength.

For thin skin:

Avoid adhesive dressings that can cause further tearing.
Use gentle, silicone-based dressings when possible.
Monitor for signs of further skin breakdown.

Moisture Balance

Healthy skin maintains moisture balance. Too much moisture can macerate (soften and break down) the surrounding skin, while dryness can lead to cracking. Dressings help maintain the right moisture level.

Hydrocolloid or hydrogel dressings add moisture to dry wounds.
Foam or alginate dressings absorb excess fluid from wet wounds.

Allergies and Sensitivities

Some people have sensitive skin or allergies to certain materials, adhesives, or topical products. Workers must check for an allergic history and look for redness, rash, or itching where a dressing is used.

Hypoallergenic or non-latex products should be chosen if someone has allergies.

Location and Area of the Body

Some body areas are constantly moving, like joints, or get pressure from lying or sitting. Dressings need to flex with movement, not peel off, and not cause pressure sores.

Use stretchable dressings on elbows, knees, or ankles.
Non-adhesive (non-stick) dressings on high-risk pressure areas.

The Skin’s Immune Functions

The skin is part of the immune system. The outermost cells form a barrier against germs, and Langerhans cells in the epidermis detect and respond to threats.

Broken skin is more prone to infection.
Dressings act as a temporary shield to block germs, reduce contamination, and support the immune system during healing.

Wound Exudate and Skin Absorption

Wound Fluid (Exudate)

Wounds may produce fluid (exudate) as part of normal healing. Too much exudate can leak onto the surrounding skin, causing maceration. Too little can slow healing. The characteristics of the skin around the wound will affect how much exudate it can handle before breaking down.

Absorbent dressings help remove excess exudate.
Moisture-retentive dressings keep drier wounds from drying out too much.

Skin Absorption

The skin acts as a barrier, but some substances can be absorbed, especially if the barrier is broken. Certain dressings contain medications (like antiseptics or silver) that are absorbed directly into the wound or nearby tissues.

Workers need to be aware of possible sensitivities and systemic effects for people with large wounds or compromised skin.

Skin Colour and Circulation

The skin’s colour can indicate the health of underlying tissue. Healthy skin is usually pink or brown, depending on natural pigmentation and blood flow. Poor blood flow may cause paleness or blueness, while infection and inflammation may lead to redness.

Dressings should not be so tight that they cut off circulation.
Check skin colour regularly under and around dressings.
Watch for any signs of pressure or localised tissue damage.

Preventing Skin Damage from Dressings

Dressings offer protection, but can also cause problems if not used thoughtfully. Workers applying dressings need to consider:

The risk of adhesive injury when using sticky tapes or dressings on fragile skin.
The possibility of pressure injuries (sores) in people at risk, such as those who are immobile.
The chance of drawing healthy skin cells away when removing stickier dressings.

To help prevent damage:

Use non-adhesive dressings on injured, weak, or sensitive skin.
Gently remove dressings, lifting the edge slowly and using adhesive remover if needed.
Check for redness or marks each time a dressing is changed.

The Importance of Aseptic Technique

The skin prevents germs and infection. Once it is broken, wound care must keep bacteria away from deeper tissues.

Workers should wash hands before and after wound care.
Use gloves to avoid contamination.
Clean wound areas as instructed, using suitable antiseptics if necessary.
Dressings should be sterile and handled carefully.

Aseptic technique protects the open layers of the skin from infection, supporting natural healing.

Application of Dressings: Linking Back to Anatomy and Physiology

Each aspect of the skin’s anatomy and physiology informs how we approach wound care.

Choosing the Right Type of Dressing

Workers select dressings based on:

The skin layer affected.
Superficial wounds (epidermis): film dressings or simple non-stick pads.
Deeper wounds (dermis and below): thicker foams or alginate dressings.
The amount and type of exudate the skin can manage.
Presence of infection — requiring antimicrobial dressings.
The area of the body and its movement.

Supporting the Skin’s Natural Healing

Dressings are used not only to cover wounds. They create the right environment for the skin to heal, supporting key functions.

This involves:

Keeping wounds moist, not wet or dry, to help new cells grow.
Preventing bacteria and foreign bodies from getting in.
Absorbing fluid without damaging new skin.
Looking after delicate and sensitive areas with gentle materials.
Making sure movement or activity does not disrupt healing.

Monitoring and Observation

The person’s skin must be checked regularly.

Look for swelling, colour changes, heat, pain, or signs of infection.
Assess whether the skin around wounds is staying healthy.
Change dressings as recommended, using sterile technique.

Care planning considers age, medical condition, location, skin sensitivity, allergies, and lifestyle.

Special Situations

Chronic Wounds

Long-lasting wounds (like pressure ulcers or diabetic foot ulcers) involve complex changes in the anatomy and physiology of the skin. Healing may take longer because the deeper layers have been damaged or blood flow is poor.

Here, workers must pay careful attention to choosing dressings that support gentle healing and prevent further skin breakdown.

Burns

Burns damage not just the outer but often the deeper layers of skin. Special dressings are chosen to:

Control pain,
Prevent infection,
Maintain temperature,
Support moist healing.

Final Thoughts

Understanding the body’s largest organ and how it works provides a strong base for safe, person-centred wound care. Applying dressings is much more than covering a sore or injury. The health worker’s knowledge of how the skin is built and how it heals guides every step, from picking the best material to how it is put on and checked later.

When workers remember the purpose and limits of each layer of skin, they make informed choices. Observation and sensitivity to the individual’s experience—pain, movement, allergies, and daily life—make a big difference. Good wound care supports the skin’s natural power to protect and heal, helping the person on their path to recovery.