Week 8 Skin Wounds Flashcards
The largest organ of the body:
The skin
Skin
Provides a protective barrier, regulates temperature, gives the dog it’s sense of touch.
Three major layers of the skin:
The epidermis/outer most layer
The dermis/middle layer
Subcutis/innermost layer
The epidermis
Composed of multiple types of cells including keratinocytes, melanocytes, Langerhans cells and Merkel cells
It provides protection from foreign substances –
The epidermis
Keratinocytes
Provide a protective layer, constantly renewed in a process called keratinization.
Keratinization
New skin cells are created near the base of the epidermis and my grade up words. This produces a compact layer of dead cells on the skin surface.
This layer keeps in fluids, salt and nutrients, well keeping out infectious or noxious agents.
Top layer of dead cells are continuously shed and replaced. The rate is affected by nutrition, hormones, tissue factors, immune cells in the skin and genetics. Disease and information also alter normal cell growth and Keratinization
Melanocytes
Located at the base of the epidermis, outer root sheath of hairs and the duct of sebaceous and sweat glands.
Melanocytes produce:
This skin and hair coloring/pigment called melanin.
Melanin production is controlled by:
Or moans and the jeans received from parents.
Melanin helps protect:
The cells from the damaging rays of the sun.
Langerhans cells
Part of the immune system. Damaged when exposed to excessive uv light and glucocorticoids (anti-inflammatory drugs).
Langerhans cells play an important role in:
The skins response to foreign substances and contribute to such things as the development of rashes.
Merkel cells
Specialized cells associated with the sensory organs in the skin.
Help provide sensory information from whiskers and the deep skin areas called tylotrich pads.
Skin Appendages
Hair follicles, oil and sweat glands and claws.
Hair follicles in dogs
Compound, a central hair surrounded by 3 to 15 smaller secondary hairs all exiting from one pore.
The function of the hair coat:
Protect the skin from physical and ultraviolet light damage and helps regulate body temperature.
Oil glands (sebaceous glands)
Secrete an oily substance called sebum into the hair follicles and onto the skin. Present in large numbers near the paws, back of the neck, rum, chin and tail area.
Sebum
A mixture of fatty acids. Important for keeping the skin soft, moist and pliable. Gives the hair coat sheen and has anabiotic properties.
Abrasion
An area of skin that has been a super Fishel he scraped, creating a word.
The phases of wound healing;
Inflammatory, Proliferative, Maturation/Remodeling
Best observed in a wound left to heal by second intention healing.
Inflammatory phase
Begins immediately and lasts 3 to 5 days.
Characterized by formation of a blood clot within the wound; release of growth factors; recruitment of macrophages and neutrophils; serves to clean up the wound and modulate healing.
The wound is at its week is during this phase.
External coaptation
Use of a rigid external device such as a bandage, splint or cast to align fractures.
Second intention healing
Hearing of a wounded by granulation tissue formation, epithelialization and contraction.
Proliferative phase
Begins after 2 to 3 days.
Characterized by invasion of fibroblasts, formation of granulation tissue, deposition of collagen epithelialization across healthy granulation tissue, and wound contraction by myofibroblasts.
Wound strength increases considerably during this phase.
Matureration/remodeling phase
Begins after about three weeks and last weeks to months.
Collagen fibers remodel and align.
Final gain in one strength occurs. But the wound will never be as strong as normal tissue.
Neutrophil
A granulocyte that is the chief phagocytic white blood cell of the blood.
Macrophage
A phagocytic tissue cells of the immune system that may be fixed or freely motile, is derived from Monocytes, functions in the distraction of foreign antigens and serves as an antigen-presenting cells.
The functions of neutrophils and macrophages
Modulate wound healing by releasing more growth factors. Also help to remove bacteria and cellular debris from the wound.
Wound strength is at its lowest during –
The inflammatory phase.
Granulation tissue
Vascularized fibrous tissue that covers a full thickness skin wound if the wound is left to heal by second intention.
Why is granulation tissue important?
It creates a barrier against infection and surface for re-epithelialization.