Integument Flashcards
Phases of wound healing
Inflammatory
Proliferative
Maturation/remodeling
Inflammatory phase of wound healing
Last up to 5 days, hemostasis, coagulation, MMPs, serine proteases, leukocyte margination, macrophages start to move in
Proliferative phase of wound healing
5-20 days, granulation tissue forms
4 processes: neovascularization/angiogenesis, fibroplasia (MMP 1,2,3 facilitate migration of fibroblast which secrete fibronectin forming loose ECM) and collagen deposition (type 3 laid first which is weak baby collagen and slowly replaced with strong type 1 collagen), epithelialization (guided by type 1 collagen), wound contraction (skin peripheral to a full thickness defect advances in a centripedal fashion toward the center of the wound)
Maturation/remodeling
type 1 collagen replaces type 3, takes from day 20 to one year
Wound contraction rate
0.6-0.75 mm /day
Contracture
loss or inhibition of motion or function as a result of excessive scar tissue or muscle atrophy or fibrosis
What is required for optimum collagen production
vitamin C
When does tensile strength increase rapidly?
after day 4-5 at which fibroplasia and early collagen deposition noted
What do fibroblasts make?
collagen
What is intussceptive growth?
process of epithelial proliferation and collagen deposition that occurs within the stretched skin to bolster and restore cutaneous areas that are under significant tension
How long does wound contraction take?
6 weeks, square and rectangular incisions contract more effectively than circular ones
3 weeks after injury, what is tensile strength of scar?
20% of final strength
Scars retain what % of tensile strength of normal skin?
70-80%
Formation of granulation tissue in cats vs. dogs
cats 19 days, dogs 7.5 days
