Skin and Wounds Flashcards
What are the main layers of the skin?
The main layers of the skin are the epidermis, the dermis, and the subcutaneous tissue (hypodermis).
What are the accessory structures of the integumentary system?
The accessory structures of the integumentary system include:
* glands (sebaceous, sweat)
* hair (hair bulb)
* nails
Describe the epidermis.
The epidermis is the outermost layer of the skin and is a stratified keratinised squamous epithelium. It has 4 layers in thin skin and 5 layers (Stratum lucidum) in thick skin.
Name the layers of the epidermis in order from deepest to most superficial.
The layers of the epidermis from deepest to most superficial are:
* Stratum basale
* Stratum spinosum
* Stratum granulosum
* Stratum lucidum (in thick skin)
* Stratum corneum
What is the function of melanocytes in the epidermis?
Melanocytes produce melanin, which protects keratinocytes from UV damage.
Describe the dermis.
The dermis is the layer of skin beneath the epidermis. It contains fibroblasts that produce collagen and elastic fibres, as well as a rich blood, lymph, and nerve supply.
What are the main components produced by fibroblasts in the dermis and what are their functions?
Fibroblasts in the dermis produce:
* collagen (providing tensile strength and binding water)
* elastic fibres (providing flexibility and stretch)
Name some of the sensory receptors found in the dermis and what they detect.
Sensory receptors in the dermis include:
* Meissner’s corpuscles: detect light pressure (fast)
* Merkel’s disks: detect light pressure (slow)
* Pacinian corpuscles: detect deep pressure/vibration
* Free nerve endings: detect pain
What is the function of sebaceous glands?
Sebaceous glands secrete acidic, antimicrobial sebum to protect, moisturise, and ‘waterproof’ the skin.
What are the functions of sweat glands?
Eccrine sweat glands and hair aid in thermoregulation, while apocrine sweat glands release lipid secretions after puberty.
How does the skin provide protection?
The skin provides protection from:
* mechanical/thermal/chemical injury
* UV radiation
* dehydration
* acts as a barrier to microbes
How does the skin contribute to detection?
The skin has receptors in the dermis that provide the special sense of touch and detect pressure, temperature, and pain.
How does the skin contribute to maintenance of the body?
The skin contributes to thermoregulation.
How does the skin contribute to excretion?
The skin allows for excretion through:
* sweat
* insensible fluid losses
* elimination of ammonia, urea, and electrolytes
How does the skin contribute to synthesis?
The skin facilitates the activation of vitamin D using UV radiation.
How does the skin contribute to storage?
The skin acts as a blood reservoir and facilitates the storage of adipose tissue in the subcutaneous tissue.
How does the epidermis contribute to protection from UV damage?
Melanocytes in the epidermis produce melanin, which protects underlying keratinocytes from UV damage.
How does the dermis contribute to the skin’s strength and flexibility?
Fibroblasts in the dermis produce collagen for tensile strength and elastic fibres for flexibility and stretch.
What are the four main stages of wound healing?
The four main stages of wound healing are:
* Haemostasis
* Inflammation
* Proliferation
* Remodelling
Briefly describe the haemostasis stage of wound healing.
Haemostasis involves an initial brief period of vasoconstriction and clotting to loosely hold wound edges together and create a barrier.
Briefly describe the inflammation stage of wound healing.
Inflammation involves vasodilation and increased membrane permeability, allowing the migration of:
* neutrophils
* monocytes
* fibroblasts
* fluid
Briefly describe the proliferation stage of wound healing.
During proliferation, fibroblasts produce a plug of fibrous tissue within the clot. New blood vessels form, and granulation tissue grows to fill the space.
Briefly describe the remodelling stage of wound healing.
In remodelling, the fibrous plug hardens to become a scab, which falls off when new skin growth is complete. Disorganised collagen fibres are modelled, and a scar may remain.
What is primary intention wound healing?
Primary intention occurs when wound edges are apposed (able to make contact), often secured with stitches, staples, or surgical glue. It typically results in minimal scarring.
