Week 2 Lecture Bites Aging And Repair Flashcards
Ageing cells cells
Normal process
Changes in structure and function
Increasingly susceptible to stress and disease
Why do cells age ?
Cell division may be limited
— cell type eg neurones, skeletal muscle
—limited capacity
Telomeres
Glucose
—increasing cross-links between glycoproteins
— loss of tissue elasticity
Autoimmunity response
Free radicals and oxidative damage
— wrinkled skin , stiff joints, hardening of arteries
Pollution, food, radiation
Tissue damage
Cells can become damaged, worn out or die
Tissue repair is the replacement of these cells
Cell division
— stroma - supporting connective tissue
— parenchyma - functional tissue
Epithelial, connective, muscular and nervous tissue
Epithelial tissue damage
Continuous capacity for renewal
Eg stem cells in skin or gut epithelia
Eg differentiated cells - hepatocytes or endothelial cells
Connective tissue damage
Capacity to renew is related to blood supply
Bone has capacity to renew
Cartilage has a reduced capacity
Muscular tissue damage
Poor capacity for renewal
Skeletal muscle satellite (stem) cells - don’t divide rapidly enough to replace extensively damaged fibres
Cardiac muscle - no satellite cells and existing cells Do not undergo mitosis
Nervous cells tissue damage
Poorest capacity for renewal
Normally do not undergo mitosis
Tissue regeneration
Parenchyma cells involved - tissue regeneration is possible
Stromatolites fibroblasts involved
—replacement tissue will be new connective tissue
—fibrosis - collagen and ECM form scar tissues
— function of tissue may be impaired
Extensive damage
—connective tissue stroma and parenchyma cells
— collagen and blood capillaries
— granulation tissue - framework for epithelial cells
Factors affecting repair
Nutrition - protein and vitamins
Blood circulation - oxygen, nutrients, antibodies
Age
-thinner epithelial cells
-fragile connective tissues
