1.1 Describe the anatomy and physiology of the skin in relation to skin breakdown and the development of pressure sores
The skin provides a tough covering for the body and is naturally acidic, which aids in infection protection. The skin is sensitive, and some areas, such as the lips and fingertips, have a higher density of nerve endings and are, therefore, more sensitive. Touch, pain, itch, hot, cold, and other sensations are registered and distinguished by the skin. The skin helps to regulate body temperature by dilation or constriction of blood vessels in response to temperature changes. When the body is hot, the skin pores open and sweat is produced as a cooling mechanism. When the body is cold, the skin constricts, the tiny muscles at the base of the body contract, and the hairs stand upright, forming what is commonly known as goose bumps on the skin. Waste products can also be excreted through the skin as sweat.
 The skin serves many purposes. It acts as a barrier against water, microorganism invasion, mechanical and chemical trauma, and UV light damage. The cell envelope, a layer of insoluble proteins on the inner surface of the plasma membrane, forms the epidermal water barrier. It is formed by the cross-linking of small proline-rich proteins and larger proteins such as cystatin, desmoplakin, and filaggrin and contributes to the barrier’s strong mechanics. And the lipid envelope is a lipid/hydrophobic layer attached to the plasma membrane’s outer surface. Keratinocytes in the stratum spinosum produce keratohyalin granules as well as lamellar bodies (a mixture of glycosphingolipids, phospholipids, and ceramides) that are assembled within the Golgi. The contents of the lamellar bodies are then secreted into extracellular spaces between the stratum granulosum and the plasma membrane via exocytosis.
Skin is composed of three layers: The epidermis, or the outermost layer of skin, serves as a waterproof barrier and is responsible for skin tone. The dermis is the skin layer below the epidermis that contains tough connective tissue, hair follicles, and sweat glands. The deeper subcutaneous tissue is made up of fat and connective tissue (hypodermis).
 Friction, shear, moisture, and pressure are all factors that contribute to skin breakdown. These factors can occur singly or in combination. Friction, moisture, and shear have all been identified as factors that contribute to pressure ulcers.
 A friction injury occurs when the skin rubs against surfaces such as a bed sheet, armrest, or brace, resulting in a scrape, abrasion, or blister. This type of injury is commonly seen on the heels and elbows and can be caused by repositioning, propping, or rubbing as a result of increased spasticity.
 A shearing injury is caused by dragging or sliding a body part across a surface and appears as a cut or tear. This type of injury can occur if you drag the button during a transfer or if you slide down in bed with the head of the bed elevated. The sliding force causes the bone to move against subcutaneous tissue while the epidermis and dermis remain essentially in the same position against a supporting surface such as a wheelchair or bed. This action causes blood vessel occlusion, which reduces blood flow, oxygen, and nourishment to the skin, eventually leading to a breakdown. A shear injury can actually tear the tissue over the tailbone, resulting in a pressure ulcer if the pressure is not relieved.
Excess moisture makes it weak and more vulnerable to friction, shear, and breakdown. Sweating, bowel and bladder accidents and wound drainage are the most common causes of excess skin moisture.
There are four stages in the breakdown of the skin that causes pressure sores:
- The skin may appear reddened, similar to a bruise. The skin’s integrity is intact, with no breaks or tears, but the area is at high risk of further breakdown.
- Skin tears wear away, and an ulcer forms.
- The sore spreads beneath the skin’s surface, forming a small crater. Due to nerve damage, there may be no pain at this stage. Tissue death and infection are very likely.
- Pressure sores worsen, causing significant damage to deeper tissues (muscles, tendons, and bones). Serious complications, such as osteomyelitis (bone infection) or sepsis (an infection spread through the bloodstream), can occur.
Other answers in the full document:
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1.2 Identify pressure sites of the body
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1.3 Identify factors which might put an individual at risk of skin breakdown and pressure sores
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1.4 Describe how incorrect handling and moving techniques can damage the skin
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1.5 Identify a range of interventions that can reduce the risk of skin breakdown and pressure sores
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1.6 Describe changes to an individual’s skin condition that should be reported
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2.1 Identify legislation and national guidelines affecting pressure area care
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2.2 Describe agreed ways of working relating to pressure area care
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2.3 Describe why team working is important in relation to providing pressure area care
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3.1 Describe why it is important to follow the agreed care plan
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3.3 Identify any concerns with the agreed care plan prior to undertaking the pressure area care
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3.5 Identify the pressure area risk assessment tools which are used in own work area
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3.6 Explain why it is important to use risk assessment tools
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4.1 Identify a range of aids or equipment used to relieve pressure
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4.2 Describe safe use of aids and equipment
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4.3 Identify where up-to-date information and support can be obtained about:
a. Materials
b. Equipment
c. Resources