Tissue Repair Flashcards
Define tissue repair
Restoration of tissue architecture and function after an injury.
What’s the response of tissue injury?
Damage- inflammation- removal of dead tissue OR replacement by…
specialised tissue (regeneration) OR fibrous tissue (scarring)
= HEALING
What are the two outcomes of tissue repair?
Regeneration
Fibrosis
Depends on regenerative capacity of tissue, nature, severity and duration of injury as to which repair.
How are tissues of the body divided?
Continuously dividing (labile) tissues
Stable tissues
Permanent tissues
What is the inflammation of tissue repair process?
Macrophages clean up dead/damaged tissue
Clot prevents blood loss
Damaged area isolated from undamaged
Systemic- activation of IS
What is the organisation step of the tissue repair process?
Fibroblasts secrete collagen to replace fibrin
New capillaries bud from undamaged capillaries
Microphages remove clot
Granulation tissue develops
What occurs in the regeneration/fibrosis step of tissue repair?
Surface epithelium regenerates Scan falls off and epithelium thickens Collagen fibres mature Scar tissue matures Scar becomes pale as blood supply to collagen diminishes
What is healing by first intention?
Occurs in small wounds that close easily
Epithelial regeneration predominates over fibrosis
Healing fast- minimal scarring
E.g. Paper cuts
What’s granulation tissue?
Consists of... New growing blood vessels Proliferating fibroblasts New matrix synthesis Inflammatory cells Purpose is to replace loss of tissue volume & to be a template for scar production.
What is healing by second intention?
Occurs in larger wounds that have gap between wound margins
Fibrosis predominates over epithelial regeneration
Healing slower
Eg infections
What can occur when wounds go bad?
Contracture
Keloid scar
Proud flesh
What’s a contracture wound?
Enlarged scars, shrinks and contract excessively becoming disabling.
Acontracture is a permanent fixture of skin
Contracture may cause serious cosmetic and functional disability
What’s a Keloid Scar?
Develops late in healing process
Excess formation of collagen
Changes in cellular signals that control growth
What is proud flesh?
Granulation tissue in excess at the edges and base of a wound
New blood vessels and fibroblasts in proud flesh
What are the clinical features of non-healing wounds?
Absence of health granulation Presence of necrotic &I unhealthy tissue in wound bed Lack of adequate blood supply Excess exudate and slough Recurrent breakdown of wound
