Tissue Repair/ Wound Healing


Local tissue level: 1. skin 2. mucous and 3. stomach acid


Injury stimulates:                 Inflammatory response

                                                                Non specific defense, prevent further damage


                                                Immune Response: specific


Tissue Repair occurs in 2 ways

                                1. Regeneration: replacement with same cells

                                2. fibrosis: replace with fibrous tissue or scar tissue

Depending on type of tissue damaged and severity determines which way to heal


Tissue Injury:

1. capillaries become permeable allows for clotting

2. granulation tissue : delicate pink tissue with large capillaries, fragile, contains phagocytes and fibroblasts (make connective tissue: collagen fibers = scar )

3. surface epithelium regenerates across granulation tissue and under the scab


Epithelial tissue and mucous membrane , fibrous and bone = heal well


Skeletal muscle= regenerates poorly if at all

Cardiac muscle and nervous tissue are replaced with scar tissue


Scar tissue is strong but lacks function of tissue it replaces, not flexible



Developmental Aspects of Cells and Tissues

                Mitosis occurs until puberty (except neuron)

                Skin and mucous membranes continue

                Liver cells stop but have the ability to replace

                Heart muscle and neurons lose ability to divide: amitotic