Section I – Multiple choice: (65 points; 2.5 points each). Bubble your answers on your scantron. 1. A motor unit refers to a. a single muscle fiber plus all of the motor neurons that innervate it b. all of the motor neurons supplying a single muscle c. *a single motor neuron plus all the muscle fibers it innervates d. a pair of antagonistic muscles e. all of the muscles that affect the movement of any given joint 2. Which of the following is NOT associated with the thin filaments
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LABORATORY REPORT Activity 2: Twitch Contractions and Summation PREDICTIONS Effect of Muscle Fiber Length on Contraction 1. As muscle fiber length increases: contraction force increases‚ becoming maximum at an optimal length‚ then decreasing at longer lengths. Effect of Stimulation Frequency on Contraction 2. As the frequency of stimulation increases‚ the force of contraction: increases. MATERIALS AND METHODS Measurement of Threshold Stimulus 1. Dependent Variable: contraction force
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skeletal muscle. Correct answer: c. one motor neuron and all of the skeletal muscle fibers it innervates. 4. The motor neuron and muscle fiber intersect at what is called Your answer : b. the inhibitory synapse. Correct answer: d. the neuromuscular junction. 5. A twitch is You correctly answered: a. one contractile response to a single action potential. 010/17/12 page 1 Experiment Results Predict Question: Predict Question: Will changes to the stimulus voltage alter the duration of the latent
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Q1 Muscle contraction can be understood as the consequence of a process of transmission of action potentials from one neuron to another. A chemical called acetylcholine is the neurotransmitter released from the presynaptic neuron. As the postsynaptic cells on the muscle cell membrane receive the acetylcholine‚ the channels for the cations sodium and potassium are opened. These cations produce a net depolarization of the cell membrane and this electrical signal travels along the muscle fibers. Through
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gastrocnemius muscle from Rana pipiens. The gastrocnemius receives signals from the action potentials of the sciatic nerve. The muscle contraction is caused by the binding of a neurotransmitter once the action potential reaches the neuromuscular junction. Stimulation of the muscle and the sciatic nerve allows for recording and measuring of these properties. We observed twitch recruitment of the nerve and muscle length-tension relationship of the skeletal muscle‚ summation of skeletal muscle contractions
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of excitation-contraction coupling in skeletal muscle fibers is that the end plate potential triggers a series of events that results in the contraction of a muscle cell. End plate potential is caused by the events that occur at the neuromuscular junction. 3. Describe the three phases of a skeletal muscle twitch. The first phase is the latent period- this is the period of time that elapses between the generations of an action potential in a muscle cell. The second phase is the contraction phase-
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The Tired Swimmer Case Two BIO: 201-104 November 11‚ 2010 Part I: Meet Annie 1. What vital signs or symptoms does Annie exhibit? a. Blurred vision and eye strain b. Hands ache and feel weak c. Gasping for air d. Weakness & Constant fatigue 2. Can you see any common features in Annie’s signs and symptoms? With blurred vision and eyestrain we must look at the optic nerve within the brain. From there‚ what could be causing the difficulty breathing and weakness
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A motor unit consists of a motor neuron and all of the muscle fibers it innervates. Motor neurons direct muscles when and when not to contract. A motor neuron and a muscle cell intersect at what is called the neuromuscular junction. Specifically‚ the neuromuscular junction is where the axon terminal of the neuron meets a specialized region of the muscle cell’s plasma membrane. This specialized region is called the motor end-plate. An action potential (depolarization) in a motor neuron triggers
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motor units‚ such as motor neurons‚ peripheral nerves‚ motor endplates‚ and muscle fibers. There are two different sites where repeated contractions may cause muscle fatigue. One is the transmission mechanism‚ which is basically the neuromuscular junction‚ muscle membrane‚ and endoplasmic reticulum. The other one is the contractile mechanism‚ which is the muscle filament. A muscle fiber’s mechanical response declines with fatigue. Peripheral muscle fatigue is caused by changes in the internal conditions
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Tissue Flap Surgery at Dr. Mangelson’s Office. Hayley and I had a good experience at Dr. Mangelson’s office. The staff was extremely friendly and welcoming. While we waited for the doctor to prepare for his surgery‚ one of the hygienists‚ Karen‚ let us into her operatory to observe her scaling a patient’s teeth. She showed us a couple of instruments she loves and gave us some tips on working in private practice. She told us about how she and some other hygienists get together in a “study group”
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