Bauer Chapter 9

3. Considering your answers to Questions 1 and 2, why did activity in Annie’s motor nerves produce a skeletal muscle response that fatigued during repetitive stimulation?

It compares three specific muscles in the human body that vary in muscle tissue type in terms of:

Muscles are made up of small fibres that contract making the whole muscle contract. There are three types of muscle fibre; Type 1, Type 2a and Type 2b. All individuals have a combination of all fibre types and their combination of fibre types is genetically determined. Different parts of the body have different combinations of fibre types.

Martini, F. H., Nath, J. L., and Bartholomew, E. F. “Muscle Tissue.” Anatomy & Physiology. 9th

2. What happens to the active force as the muscle length is increased from 50mm to 100mm?

Review Sheet Results 1. Describe how increasing the stimulus frequency affected the force developed by the isolated whole skeletal muscle in this activity. How well did the results compare with your prediction? Your answer: When the stimulus frequency was at the lowest the force was at its lowest level out of all of the experiments. As the stimulus frequency was increased to 130, s/s the force increased slightly but fused tetanus developed at the higher frequency. When the stimulus frequency was increased to the amounts of 146-150 s/s, the force reached a plateau and maximal tetanic tension occurred, where no further increases in force occur from additional stimulus frequency. 2. Indicate what type of force was developed by the isolated skeletal muscle in this activity at the following stimulus frequencies: at 50 stimuli/sec, at 140 stimuli/sec, and above 146 stimuli/sec. Your answer: At 50- Unfused

 1)Flexion happens when a decrease in the angle between two body segments happens like in the shoulder, elbow, hips and knee joints. An

types of muscle tissues : skeletal, cardiac, smooth. Each of these different tissues has the ability

The contraction of the extent which the The direction which the bone of the joint move depends on the contraction of the muscle.

Post-lab Quiz Results You scored 50% by answering 2 out of 4 questions correctly. 1. Which of the following is not one of the ways that the body can increase the force produced by a skeletal muscle? Your answer: b. application of high-frequency stimulation by a motor neuron Correct answer: d. application of higher voltages to the whole muscle 2. When a muscle receives a stimulus frequency that causes non-overlapping twitches to follow each other closely in time such that the peak tension of each twitch rises in a stepwise fashion up to a plateau value, the result is known as You correctly answered: c. treppe. 3. In this experiment the isolated skeletal muscle was repetitively stimulated such that individual twitches overlapped with each other and resulted in a stronger muscle contraction than a standalone twitch. This phenomenon is known as You correctly answered: c. wave summation. 4. Wave summation is achieved by Your answer: c. summating action potentials so that their depolarizing magnitude is greater. Correct answer: a. increasing the rate of stimulus delivery (frequency)

8. What stretch resulted in the highest contraction force? What happens to the muscle at the highest stretch levels?

Muscular endurance is very important for people playing sports and who have to sustain an activity for long periods of time. Muscular endurance is determined by how well your slow twitch muscle fibers are developed. In case your wondering what slow twitch muscle fibers are, I will explain. There are generally two types of muscle fibers in your body, slow twitch and fast twitch. Slow twitch muscle fibers cannot exert as much force as fast twitch, but can sustain an effort over a much greater period of time. Fast twitch muscle fibers can exert a great amount of force but for a very limited amount of time. Therefore, slow twitch equals endurance, while fast twitch equals strength.

Muscle hypertrophy refers to muscular enlargement resulting from resistance training, On the cellular level muscle hypertrophy is increased by the expansion of cross-sectional area of the existing muscle fibers. (Goldburg, 1973) The adaptation of muscle in the world of strength and conditioning can give an athlete the potential to become bigger, faster, and stronger. Since being big, fast, and strong is an advantage in many sports, this means that much of the time that a strength and conditioning coach has revolves around the goal of getting their athletes to see muscle hypertrophy. On just one level this desire is a driving force behind the large amount of research and competiveness in the industry to produce extremely high level college and professional sport athletes. Exercise physiologists conduct research studies and form experiments so they can test new techniques in exercise so they can better understand and optimize muscular hypertrophy.

Muscle Fibre Tear- When the muscles contract they create micro tears within the muscle and require protein in order to mend the muscles. These tears are repaired into stronger and denser fibres. For example if an individual went on the treadmill for 10 minutes, the hamstrings,

4. __ are muscles that act like voluntary muscles but actually they cannot be moved at will.