Today we did a 'walk through' of what muscle contraction would look like. One student was the brain in the situation. The brain sent a message 'an action potential' through another student who was acting as a neuron. When the message got down to the neurons hand (the neruomuscular junction) ACh (a squirtbottle) was released to allow the action potential across the sarcolemma, through a passageway of chairs (the t-tubules) into the sarcoplasmic reticulum (the corner of the room), students who were Ca+ ions then were released into the sarcomere. The Ca+2 students could then shift the ace bandages (tropomyosin) that covered the myosin binding sites (rubber bands) on the actin (other students). Students who were myosin could now grab onto the rubber bands and slide the actin together reducing the space between the z-lines and making the H-zone disappears. When a sarcomere contracts, the myofibril contracts, causing the muscle fiber to contract and then the muscle contracts.
Homework - Test on Monday
Objectives - Students will name the components of a skeletal muscle fiber and describe the function of each. Students will explain how skeletal muscle fibers are innervated and how they contract. Students will describe how ATP is made available for muscle contraction.