33:630:363 Lecture Notes - Lecture 1: Sarcopenia, Lipogenesis, Skeletal Muscle
14 Jan 2020
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Document Summary
Sarcopenia: characteristics as natural part of the aging process: gradual decline in skeletal muscle mass quality and quantity, subsequent decline in strength and/or performance. Aging promotes a decrease in muscle mass and. Increase in visceral lipogenesis: decline in protein synthesis and cell mass, decline in physical activity, increase in proteolysis (diminished sex hormones and increase in pro-inflammatory cytokines) Changes in body composition: 22 years old, 48% muscle, 19% fat, 33% non-muscle fat free mass, 76 years old, 25% muscle, 35% fat 40% non-muscle fat free mass. Development of sarcopenia: aging and inactivity = decreased protein synthesis, illness and injury = increased protein breakdown, decreased synthesis and increased breakdown = loss of lean body mass. Constitutional factors: female sex, low birth weight, genetic susceptibility. Lifestyle factors: malnutrition, low protein intake, alcohol abuse, smoking, physical inactivity. Living conditions: starvation, bed rest, immobility, deconditioning, weightlessness. Aging process: increased muscle turnover, reduced number of muscle cells, hormonal deregulation, changes in neuromuscular system.
