Exam 7 th Monday Feb 24 Muscle making ATP figure 9 22 Creatine phosphate o Initial source of ATP o Limited supply o Supply replenished during relaxation Glycolysis o Used alone during intense or prolonged activity o Can be anaerobic independent of oxygen supply o Replenished during relaxation Oxidative phosphorylation ETS o Continued supply during moderate exercise comes from aerobic glycolysis What s missing from this figure Krebs Cycle Krebs cycle takes that pyruvate and goes into oxidative phosphorylation o Amino and fatty acids start there Whole muscles figure 9 29 Contraction produced by cross bridge cycling o Generates a force tension o Opposed by the load Bones muscles flesh The forearm has weight itself more force generated than the weight applied o Muscle shortening depends on tension load It is wrong to think that contraction shortening Isometric no changes in muscle length Tension is less than the load e g pushing against a wall muscle cannot actually move something no lifting shortening happens but still has contraction Isotonic no changes in tension muscle shortens Referring to a particular tension e g college students won t pay one penny more for their lunch Eccentric lengthens because L T The muscle contracts while goes further away from the direction of tension when the load wins weigh too big shortened sarcomere I band H zone Isotonic contraction figure 9 17 o Degree of contraction related to load Initial period of isometric contraction tension load Shortening begins after tension load To get to the isotonic contraction one first has a period of isometric contraction where the tension is increased In the figure the purple one takes longer time to start e g weightlifting o Relationships Increased load Increased latency Decrease velocity Decrease response Impact of repeated stimulations APs figure 9 20 Bigger load longer time inverse relationship o Tension is summed just as we build on depolarization of one neuron with another depolarization o Maintained contraction tetanus if you are invaded by a parasite the toxins that parasite creates can cause stimulation and tension can happen You get the shot prevents your body from being a nice home for the critters You want tetanus to happen in your body You have tetanus happening in your body now the unfused kind Unfused incomplete tetanus maintaining contraction but allow partial relaxation between stimuli Very rapid sequence of stimuli occurs with higher frequency stimulation 20 40 stimuli sec Fused tetanus no time between stimuli to return Ca 2 Higher potential level Max contraction happens too quick for the Ca 2 to restore ATPase cannot catch up so a bigger tension happens non of the Ca 2 get put away Differences between myofibers figure 9 15 1 According to Speed of contraction o Fast vs slow Fast Cross bridge cycles down quickly breaking down of ATP to do the next reach out quickly high ATPase activity Low waits for enzyme to do job then can continue cycle o Differ with respect to amount of ATPase activity More enzymes to do this job the enzyme do the job very quickly how quickly ATP is used by the cells o Hydrolyzing ATP on cross bridge Energizes so it can reach any remaining Ca 2 1 ATP used in 1 cycle Which one use ATP more quickly The faster one Feb 26 th Wednesday 2 According to Mechanism for making ATP o Oxidative o vascularized myglobin More bold flow myoglobin is the O2 source O2 available and get vascularized Oxygen small non polar cross the plasma membrane with no difficulties 1 gradient go inside 2 once the gradient changes the O2 wants to go outside we catch the oxygen with myoglobin Once bind to a protein cannot go across the membrane o Glycolytic anaerobically o Few mitochondria glycogen Three types of fibers figure 9 24 9 25 9 26 1 Slow oxidative low ATPase Slow enzyme getting energy oxidatively Use ATP slowly making many ATP 2 Fast oxidative glycolytic high ATPase Use ATP fast good at making ATP but use a little bit faster than make 3 Fast glycolytic high ATPase high glycolytic Power lifter Fast glycolytic Runner Fast oxidative glycolytic Most muscles are mix of types o High oxidative level red More myoglobin more oxidative Myoglobin creates the red color In McDonald s instead of saying give me some dark meat you say give me some oxidative focused meat o High glycolytic level white Genetic basis However sprinter and marathoners proportion can be modified Impact of use disuse o Changes muscle structure and or function o Disuse atrophy diseases too o Use hypertrophy exercise too Increase the size of muscle fibers as well as ATP production anaerobic or aerobic Aerobic Increase vascularization Increase of mitochondria in muscle fibers Increase endurance with decreased fatigue Exercise that is low intensity but long duration Anaerobic High intensity exercise such as weight lifting Increased myofiber diameter Increased glycolytic enzymes Controlling body movement Motor commands originate in motor cortex o Motor output mapped too Voluntary movement similar to reflex
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