DO NOW WHAT HAPPENS WHEN YOU WORK OUT WITHIN YOUR MUSCLES? (THINK BACK TO BIO AND THE TOPIC OF CELLULAR RESPIRATION!)

MUSCULAR RESPONSES

OBJECTIVES TO EXPLAIN WHAT HAPPENS DURING MUSCULAR FATIGUE TO IDENTIFY DIFFERENT MUSCULAR RESPONSES TO LABEL AND EXPLAIN THE DIFFERENT STAGES OF CONTRACTION

MUSCLE FATIGUE CELLS UNDERGO BOTH AEROBIC AND ANAEROBIC RESPIRATION TOO SUPPLY AMPLE ATP (LACTIC ACID FERMENTATION) LACTIC ACID CREATES AN OXYGEN DEBT BECAUSE THE LIVER CELLS MUST NOW USE OXYGEN TO BREAK DOWN THE LACTIC ACID (CAN TAKE SEVERAL HOURS) LACTIC ACID LOWERS THE PH, WHICH DIMINISHES THE MUSCLE FIBERS RESPONSE TO STIMULATION MORE EXERCISE = MORE GLYCOLYTIC ENZYMES = INCREASED CAPACITY FOR GLYCOLYSIS= INCREASED CAPACITY FOR AEROBIC RESPIRATION!! … START WORKING OUT

MUSCLE CONTRACTION A MUSCLE FIBER WILL CONTRACT AFTER THRESHOLD STIMULUS HAS BEEN REACHED. ONCE STIMULATED, THE ENTIRE FIBER COMPLETELY CONTRACTS WHICH IS CALLED THE ALL-OR-NONE RESPONSE. *THE EXTENT OF SHORTENING DEPENDS ON RESISTANCE.

MYOGRAM TWITCH= SINGLE MUSCLE CONTRACTION LATENT PERIOD: TIME BETWEEN STIMULATION AND RESPONSE PERIOD OF CONTRACTION: MUSCLE IS CONTRACTED RELAXATION: FIBER RETURNS TO FORMER LENGTH

HYPERTROPHY VS. ATROPHY HYPERTROPHY- MUSCLES RESPOND TO EXERCISE AND ENLARGE SLOW TWITCH FIBERS ACTIVATED BY LOW INTENSITY EXERCISE SUCH AS SWIMMING OR RUNNING, DEVELOP MORE MITOCHONDRIA AND CAPILLARIES, PROLONGING FATIGUE FAST TWITCH FIBERS ACTIVATED BY WEIGHT LIFTING CAN PRODUCE NEW MYOFILAMENTS & ENLARGE THE MUSCLE (THEY ARE STILL FATIGABLE) ATROPHY- WHEN REGULAR EXERCISE STOPS, CAPILLARY NETWORKS SHRINK, MITOCHONDRIA DECREASE, ACTIN & MYOSIN DECREASE, AND MUSCLE SHRINKS.

TYPES OF GRAPHS TWITCH- FULL CONTRACTION SUMMATION- FORCE OF EACH TWITCH COMBINES INCOMPLETE TETANUS- MINIMAL AMT. OF RELAXATION AFTER EACH STIMULUS COMPLETE TETANUS- NO RELAXATION, CONTINUOUS CALCIUM ION DEPOSIT

TETANUS CAUSED BY CLOSTRIDIUM BACTERIA PRESENT IN SOIL BACTERIA PRODUCES A NEUROTOXIN WHICH BLOCKS THE RELEASE OF INHIBITORY NEUROTRANSMITTERS.

ISOMETRIC VS. ISOTONIC ISOMETRIC- NO CHANGE IN MUSCLE LENGTH ISOTONIC- MUSCLE LENGTH CHANGES