Skin functions and properties Flashcards
What is the largest single organ in the body?
Skin is the largest single organ in the body.
What are the four main tasks of the skin?
- Acting as a semi-permeable barrier to protect the body from physical and biological threats.
- Controlling heat flow in and out of the body to maintain a fixed internal temperature.
- Providing stiffness to maintain body shape
- while allowing flexibility for movement.
- Allowing sensory signals to pass into the body, providing the sense of touch.
How does the body lose heat?
he body can lose heat through four main methods:
- Conduction: Transfer of heat to the air or ground.
- Convection: Wind-chill effect as air passes over the body. occurs when air or water moves over the skin, carrying away heat. For example, the “wind-chill” effect makes you feel colder on a windy day because the moving air enhances heat loss from your skin.
- Radiation: Emission of infra-red radiation when the body is hotter than its surroundings.
- Evaporation: Sweating, especially when the surroundings are hotter than the body.
What are the three main layers of the skin?
- Epidermis: The outer layer, containing the stratum corneum, α-keratin, pigments, and immune cells.
- Dermis: The mid-layer, with sub-epidermal connective tissue and corium, containing collagen, elastin, blood vessels, hair roots, and nerves.
- Hypodermis: The innermost layer, containing loose connective tissue, fatty tissue, larger blood vessels, and sweat glands.
What is the role of collagen and elastin in the skin?
Collagen provides mechanical strength to the skin, while elastin allows for elasticity, giving the skin flexibility.
How is the stress-strain curve for skin described?
The stress-strain curve for skin is a J-shaped curve due to its composite nature, combining collagen and elastin in a polysaccharide matrix.
What are Langer’s lines?
Langer’s lines are the orientation lines of collagen fibres in the skin. Surgical incisions along these lines help minimise scarring.
Describe the process of wound healing in the skin.
Wound healing in the skin involves:
- Initial inflammatory phase: Blood vessels contract, and platelets form a clot.
- Proliferative phase: Fibroblasts lay collagen, capillaries form, and a new epithelial layer develops.
- Remodelling phase: Stronger skin forms, although scar tissue may lack full flexibility.
What materials are used for sutures, and why?
Sutures are often made from catgut (from sheep), which can absorb into the body, assisting with wound closure and healing.
What are the challenges in developing artificial skin?
Artificial skin must mimic natural skin’s flexibility and texture, and it must attach strongly to the wound bed to act as a temporary protective barrier.
