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Muscle Review
Review of Muscles: Good idea to check out
| Question | Answer |
|---|---|
| How many cross bridges does it take to move a thin filament? | Many; remember that you're in a 3D world |
| Which is the thick filament? Thin? | Myosin. (Thin: Actin) |
| Why don't we have excitation all the time in muscles? | Tropomyosin is on the thin (actin) filament |
| So what do we do to get movement? | Increase Calcium |
| What do the increase in calcium ions lead to? | They bind to troponin on thin filaments and make troponin change shape |
| What does this change in shape of troponin lead to? | Moves tropomyosin, which exposes the actin |
| How do we get to an increase in calcium, then? How do we get to an increase in calcium, then? | AP makes SR, which stores calcium, to release some |
| What does the SR wrap around? | T- Tubule |
| So, we're done with the excitation, how do we get the muscle to relax? | Use ATP to get calcium back into sarcolemma and ACh breakdown |
| MUSCLE II | MUSCLE II |
| Twitch contractions: | Contraction with a SINGLE AP |
| What is the latent period? | Delay before shortening |
| What is summation? | Increasing AP leads to increase in tension and shortening |
| What causes summatioN? | Calcium not having time to get back in SR--> increases tension |
| What is the relationship between velocity of shortening and load size? | indirect relationship! As load size increases, velocity of shortening decreases. Logically: It is hard to life a heavy object; you only carry it so far, right? |
| What happens to the rate of ATP breakdown as the muslce is contracting? | CONTINUES TO INCREASE |
| How can muscle fibers form ATP during contractle activity? | 1. Transfer phosophate from creatine phsophate to ADP 2. Oxidative phosphorylation of ADP in mitochondria 3. Substrate level lphosphorylation of ADP in glycolytic pathway |
| What causes muscle fatigue? | Internal changes in acidity; phosphate concentration; glycogen depletion; excition contraction coupling failure NOT by a lack of ATP |
| What happens as a result of muscle fatigue? | ATPase pump area decrease in Acidity stop sus from getting Ca from SR |
| TYPES OF FIBERS BELOW | TYPES OF FIBERS |
| What do oxidative fibers have that the glycolytic don't? Thus, what can they do that the other one ccan't? | They have mitochondria and can carry out oxidative phosphorylation |
| Which one can develop a greater maximal tension? Why? | The glycolytic, because they're bigger |
| Slow oxidative characteristics: | Low myosin-ATPase activity and high oxidative capicity |
| Fast oxidative characteristics: | High myosin-atpase activity and HIGH oxidative capacity |
| Fast glycolytic: | High myosin-atpase ativity with HIGH glycolytic capacity |
| Which of the above is MOST resistant to fatigue? Least? Middle ^_^? | MOST resistant: Slow oxidative. LEAST: Glygolytic Middle: Well, Farah, what's LEFT?? |
| MUSCLE III | MUSCLE III |
| Muscles that produce delicate movements have how much fibers per motor unit? | Few fibers |
| How much fibers per m.u. do fast glycolytic fibers have? | LOTS |
| Why is recruitment needed? What is the order of recruitment in regards to muscle fibers from first to last and in what contraction strenght? | Increasing muscle tension---Slow Ox in weak contractions to fast ox to fast gly in strong contractions |
| What does shortening velocity depend on? | 1. Load, types of motor units, and recruitment |
| What does muscle mass measure? | Size of the muscle NOT the number of muscle fibers |
| What does movement around a joint require? | Two antagonistic groups of muscles; one flexes and another extends at the joint |
| CROSS BRIDGE ACTIVATION OF SMOOTH MUSCLES | CROSS BRIDGE ACTIVATION OF SMOOTH MUSCLES |
| What is the first step in activating smooth muscles? | Inrease calcium leads to calcium binding with CALMODULIN |
| Step 2: | Activate MYOSIN-KINASE |
| Step 3: | phosphorylated myosin binds to actin to get cross-bridge cycling |
| What is the rate of ATP splitting in smooth muscle myosin? | SLOW, so not as fast cross bridge cycling |
| Why is this mainly? | Because there are no straitions in smooth muscles |
| What can cause depolarization in smooth muscles? | 1. RAndom electrical activity in fiber's PM, neurotransmitters released by ANS, and some sort of stimuli |
| CONTROL OF BODY FUNCTION | CONTROL OF BODY FUNCTION |
| MOTOR SYSTEM HIERARCHY | MOTOR SYSTEM HIERARCHY |
| Highest level does what? | Determines intention of an action (flex my leg) |
| What is a structure involved in this? | Association cortex |
| What does the middle level do? | Deteremines movements needed to carry out action (what do I need to do to flex my leg) |
| Structures? | Cerebellum |
| Lowest level determines? | Which motor neurons will be activated |
| Through what strucutre does most input to motor neurons go through? | INTERneurons |
| What controls muscle length and tension in legnth/ | Muscle spindle stretch receptors |
| How do the MSSR (above) work? | Stretch reflex where motor neurons of IPSILATERAL ANTAGONISTS are inhibitied, but those of synergists are activated |
| Example of MSSR? | The knee jerk |
| How do you detect unexpected deviations from an intended movmenet? EX) You pick up a carton of milk you thought was full, but is empty. What motor neurons must be activated? | Alpha and Gamma |
| What montiors tension in organs? | Golgi tendon organs |
| How does they do this? | Inhibitory contracting muscle and excitate ipsilater antagonists |
| So do they inhibit alpha or gamma neurons? | Alpha. No idea why. |
| What does the flexion (or withdrawl) sequence involve? | Excite episilateral flexor muscles and hinhibit ipsilateral extensors |
| When would you apply this sequence? | When walking! |
| Huh? | You're trying to flex your leg (at the knee), so what you do is you don't extend, otherwise you're walking really stiff. Imagine walking without bending your knee. It doesn't happen. This sequence allows you to FLEX your knee and walk. |
| What does the crossed-extensor refelx do? | Excites contralateral extensor muscles during excitation of the ipsilater flexors |
| When would we apply this sequence? | When we're trying to prevent a fall by balancing |
| HUH???? | Imagine you're walking, but your left knee doesn't bend. You begin to lose your balance. So what happens is your RIGHT (contralateral) EXTENsor muscles EXTEND your right leg to help it support more weight. THUS, you don't fall down! |
| What does the sensorimotor cortex do? | Controls motor movmenets |
| What does the subcortical and brainstem nuclei do? | Determine direction, force, and speed of movements (remember they are the MIDDLE controlers) |
| ***What is the most important motor pathway that takes an AP from the brain to the skeletal muscle???? | Corticospinal pathway |
| Hypertonia vs. hypotonia? | Too much muscle tone vs. too little tone |
Created by:
talkglitter2486