Tissue Repair

Tissue Repair Wound healing Two ways: Regeneration: replace destroyed tissue by same kind of cells

Tissue Repair Wound healing Two ways: Regeneration: replace destroyed tissue by same kind of cells Fibrosis: form scar tissue (dense fibrous connective tissue) Depends on: Type of tissue damaged Severity of injury

Steps to Tissue Repair:

1. Inflammatory Reaction capillaries dilate bringing more WBC’s and clotting factors clot forms and prevents loss of blood surface dries forming a scab

2. Granulation tissue forms Delicate pink tissue with new capillaries Connective tissue produces collagen fibers Epithelial cells multiply over granulation tissue

3. Surface epithelium regenerates Surface epithelium thickens Fibrous tissue matures – forms scar tissue

Regenerative Capacity of Different Tissues Extremely Well Moderate Weak Virtually None (mostly scar tissue) Skin epidermis Mucous membranes Fibrous connective Blood Bones Smooth muscle Tendons, ligaments Skeletal muscle Cartilage Cardiac muscle Nervous tissue

Tissue Origin

3 Primary Germ Layers ectoderm mesoderm endoderm Tissues originate from the 3 primary germ layers: ectoderm mesoderm endoderm

1. Ectoderm - Nervous Epidermis

2. Mesoderm - Muscle Connective tissue Bone

3. Endoderm - mucosa (GI tract) glands mucosa (GI tract) glands

How Tissue Changes Occurs with age

Tissue Changes epithelium thins collagen (a protein) decreases easily penetrated collagen (a protein) decreases tissue repair becomes less efficient bone, muscle, nerve degeneration Causes: due in part to a decrease in circulatory efficiency poor diet, also

The End