March 27, 2017 Journal: How does exercise lead to muscular hypertrophy?

Muscular Energy

Sources of Energy The food you eat is broken down and stored by your body This stored energy can then be used later to make ATP

Muscular Fuel Glucose Glycogen Adipose Tissue Simple sugar Main source of energy Glycogen Stored in the muscles Converted into glucose when needed Adipose Tissue Stored in muscles that are used often Ex: legs

Energy Muscles use ATP as their energy ATP is made by adding a phosphate group on to ADP + ATP P P P P P Partially charged battery Fully charged battery

Three Phases of Exercise Phosphagen System Glycogen-Lactic Acid System Aerobic Respiration

Phosphagen System Occurs immediately when you begin exercise Muscle cells separate creatine phosphate Use the phosphate to convert ADP to ATP Only lasts for about ten seconds

Glycogen-Lactic Acid System Glycogen stored in muscles is split to form two glucose molecules Lactic acid fermentation makes glucose into ATP Lasts for about 90 seconds

Aerobic Respiration Glucose is broken down to form ATP Requires oxygen Allows for prolonged exercise

How do your muscles get the oxygen they need? Increased breath rate Increased blood flow to working muscles Diversion of blood flow away from nonessential organs Increased cardiac output

Why are our muscles red? Muscle cells have a molecule called myoglobin that stores oxygen in its cells. This molecule gives muscle cells their red color. Dark meat = slow twitch muscles, endurance heavy supply of oxygen; White meat = fast twitch muscles, fast action lower supply of oxygen and blood vessels. 11

Are all muscles red? Slow Twitch Muscle Fibers Endurance muscles Small in diameter Lots of myoglobin = red Aerobic respiration Fast Twitch Muscle Fibers Fatigue rapidly Large in diameter Little to no myoglobin – not red Anaerobic respiration

Excess Heat These reactions create heat as a biproduct Heat must be released Sweat Vasodilation If your body cannot get rid of heat fast enough it may lead to heat stroke