Muscle Physiology
Muscles are AMAZING! Incredibly sophisticated Fuel efficient Long lasting Self-healing Grow stronger with practice They do EVERYTHING from walking to keeping your blood flowing!
What do muscles do? Movement of skeleton Body functions Expression Speaking, singing, facial expressions, writing, dancing, fighting, etc…
Muscle Issues Sprain or Strain? Cramps? What’s happening? How to prevent?
Muscle Sprain vs. Strain Sprain = injury to the ligament Strain = injury to the muscle or tendon
Cramps!
Causes? Heat Heavy exercises Dehydration Some medicines
Prevention?
Muscle Contraction Physiology Animations Mechanics of muscle contraction Function of neuromuscular junction Contraction and nerve impulse Sacromere contraction Sliding Filament Theory
Oxygen supply & Cell Respiration Hemoglobin is bonding site for O2 in blood Gives blood red color Myoglobin Gives muscle color Is a bonding site for O2 in muscles Temporarily stores O2 in muscles
Oxygen debt Aerobic respiration Anaerobic respiration O2 needs are met Produces 34 ATP molecules/glucose Low lactic acid Anaerobic respiration Need more O2 than you have Pyruvic acid made during glycolysis breaks into lactic acid Low ATP (2 ATP molecules/glucose)
What happens to the lactic acid? Enters blood stream Moves to liver Makes glucose from lactic acid this requires ATP and O2 Muscles also need to replenish ATP SLOW PROCESS = OXYGEN DEBT Results= sore muscles!
Muscle Fatigue Exercise to strenuous for too long Rigor Mortis Ca2+ ions increase (contraction) Decrease of ATP (no relaxation) Lasts about 72 hours post mortem
Muscle Response Threshold stimulus All-or-none response Minimum stimulation needs for an isolated muscle fiber to contract These can vary! All-or-none response Skeletal muscle either contracts or not NO PARTIAL
Muscle contraction Twitch A single contraction Fraction of a second in length
Types of twitch Slow Fast Fatigue resistant (oxidative) Lots of O2 More mitochondria Better capillary network Fast Fatigue easily (glycolytic) More filaments = wider muscles It’s all about fatigue!
Muscle contraction Summation Tetanic contraction Series of stimulus of increasing intensity Contraction of muscle builds then relaxes Tetanic contraction Contraction severe Builds in intensity Does not relax! Just relax! I can’t!
Muscle contractions Sustained contractions Whole muscle contractions Allow our movements Muscle fibers are always under sustained contractions MUSCLE TONE NO muscle tone = collapse