Skeletal Muscle Physiology Physioex Exercise 2

1) Make a graph of resting heart rates from Activity 1. Provide a physiological explanation for fluctuations in resting heart rate over time. Discuss a couple of extrinsic factors that influence the autonomic nervous regulation of resting heart rate.

1. Strength is operationally defined as the maximal force that can be exerted in a single effort. Using this definition, strength should be assessed using one repetition maximum (1 RM), though we often estimate strength using tests that may involve multiple repetitions.

Exercise 7: Respiratory System Mechanics: Activity 2: Comparative Spirometry Lab Report Pre-lab Quiz Results You scored 100% by answering 5 out of 5 questions correctly. 1. A normal resting tidal volume is expected to be around You correctly answered: d. 500 ml. 2. Which respiratory process is impaired the most by emphysema? You correctly answered: c. expiration 3. During an asthma attack You correctly answered: b. inspiration and expiration are impaired. 4. During moderate aerobic exercise, which respiratory variable increases the most? You correctly answered: a. tidal volume 5. Inhaler medications for an asthma patient are designed to You correctly answered: b. dilate the patient's bronchioles.

Answer all ten (10) multiple choice questions in the Multiple Choice Answer Grid provided at the end of section 1. All questions are of equal

Individual muscles are made up of individual muscle fibers and these fibers can be further organized into a motor unit grouped within each muscle. A motor unit is simply a bundle of grouped muscle fibers. When you want to move the brain instantaneously sends a signal or impulse through the spinal cord that reaches the motor unit. Muscle fibers are cells like the basic building block of the muscle. There are a few different types of muscle fibers, each are designed for a specific type of muscle activity. Some muscle fibers are good for endurance exercises, other work best for the short bursts. Each muscle fiber is a single cell. Each cell consists of a structure.

2. Why did increasing the voltage from 3 volts to 4 volts increase the force

Description of subjects and methods: This particular study pertaining to the effect of pre-exercise creatine ingestion on muscle performance in healthy aging males was a double blind, cross-over design with repeated measures in which participants of the study ingested creatine, and a placebo, depending on their randomized assignment to a group separated by seven days, and three hours prior to performing chest press and leg press repetitions until muscle fatigue occurred. After ingesting either the creatine or placebo, the participants were instructed to refrain from caffeine, alcohol, food, drinks, and physical activity but water was permitted to the participant's amount of choosing. Seven days were spread between testing to guarantee that adequate muscle recovery between sessions was

1. Discuss the relationship between distribution of muscle fiber type and performance. How might exercise training modify or change a person’s fiber-type distribution?

The nervous system is made up of three vital parts; the brain, spinal cord and nerves. This system controls everything we do from breathing, to running to making our heartbeat fast or slow. The nervous system is very complicated although it can be broken down into smaller components.

The musculoskeletal involves the muscles and skeletal system which consist of bones supporting the bodyweight. The muscles and bones help in movement and maintaining body position through the physiological process of contraction and relaxation, muscles pulling on the bones. The skeletal systems also consist of cartilages and ligaments important for bone connection and stability with connective tissue. The muscles get attached to the bone by the connective tissue enhancing contraction and relaxation in movement. The muscles contain long muscle fibers responsible for the contraction and relaxation. The fibers contain bundles some of which allow slow movement described as slow twitch and fast twitch which ensure fast movement. The process of movement involves coordination between the musculoskeletal system and nervous system. In the process of muscle contraction to enhance movement the following takes place. (Arthur Guyton, 2006)

1.a) Contractile protein molecules that are seen in skeletal muscle fibres are actin (thin filaments) and myosin (thick filaments). Together, they produce the force of muscle contractions by forming cross bridges, and moving via a power stroke. The regulatory proteins that are seen within a skeletal muscle are troponin and tropomyosin. These proteins play a role in starting or stopping muscle contractions. When a muscle fibre is relaxed, there are no contractions because actin is unable to bind with the cross bridge. This is because tropomyosin covers the myosin binding sites on the actin proteins. In addition, troponin is not bound to calcium when a muscle fibre is relaxed, thus keeping the tropomyosin in its blocking position. When calcium enters the muscle fibres, it binds with troponin. This binding causes the tropomyosin to move away

The muscles produce more energy as skeletal movements increase when you do this test as they would for any type of exercise, and the circulatory system's activity during exercise enhances the supply of fluids, oxygen and nutrients your muscles need for energy production. The circulatory system plays a strong part in helping your body to balance and maintain healthy chemical strengths during exercise. Your circulatory system's veins work harder circulating waste-rich blood back to your heart during exercise and pumps faster so your heart contracts and pushes the blood into the pulmonary artery; and your lungs absorb carbon dioxide from the pulmonary artery and expel the toxic gas from your body each time you exhale. The Capillary beds in your

Neuromuscular junctions play a key role in skeletal muscle contractions, and they consist of axon terminals, synaptic clefts, and junctional folds. The contraction begins with the arrival of a nerve impulse at an axon terminal which causes acetylcholine (ACh) to be released into the synaptic cleft. ACh then diffuses across the synaptic cleft and binds with receptors on the sarcolemma of skeletal muscles. This binding creates electrical events that allow an action potential through muscle fiber which causes a muscle contraction. However, normal communication between a muscle and nerve can be interrupted due to the neurological disorder, myasthenia gravis. In Latin and Greek, Myasthenia gravis means “grave muscle weakness,” (fact sheet). As stated

The Pacinian corpuscle and free nerve ending will likely not have a membrane protein that recognizes other molecules because their stimulus modality are not chemical unlike the olfactory receptors.

1. Why does the force begin to decrease with time? Note that a decrease in force indicates muscle fatigue.