CHAPTER 3: THE MUSCULAR SYSTEM Three Types of Muscle * Muscle tissue is a collection of cells that shorten during contraction which create tension that results in movement * Tendons are touch bands of connective tissue that join muscle with bones Skeletal muscles * Muscles that are attached to bone (by tendons and other tissue) * Comprise 30 to 40% of human body weight * Humans have conscious control (conscious muscle) over these muscles (the brain can tell them what to do)
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Kathleen thomason October 2‚ 2012 Skeletal Muscle physiology exercise Electrical Stimulation name each phase of a typical muscle twitch and on the following line. Describe what is happening in each phase. a) latent- is a short period between the time of stimulation and the beginning of contraction b). Contraction – at this stage the muscle reaches its peak in contraction. Relaxation -Muscle is shortened‚ returns to zero and back initial length.
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sites and myosin filaments which are a thick‚ contractile protein filament‚ with Myosin Heads. These filaments slide in and out between each other to form a muscle contractions‚ this is why it is known as the sliding filament theory. Firstly I am going to explain how the filaments slide. In a relaxed muscle the cross bridges are detached from the actin filaments. When you muscle contracts they attach themselves and provide a contractile force. The thick filaments are made up of myosin molecules
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- When Calcium binds to troponin‚ it changes shape‚ which moves tropomyosin away. This uncovers the actin binding site‚ which allows myosin to bind to actin and begin contraction. * Tropomyosin - Covers the myosin binding sites on actin. * G-actin 11. Myosin molecules make contact with actin via what structure? Cross-bridges - The chemical bond myosin molecule forms with the actin molecule 12. What is the contractile unit of skeletal muscle? Myofibrils - Makes up striated muscle
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A&P Exam #3 Ch 9&10 1) Know the four (4) functional characteristics of all muscle tissues -Excitability or Responsiveness- The ability to receive and respond to a stimulus that is any change in the environment whether inside or outside the body. In the case of muscle ‚the stimulus is usually a chemical for example - a neurotransmitter released by a nerve cell‚ or a local change in ph. The response is generation of of an electrical impulse that passes along the sarcolemma of the
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Question 1 1 out of 1 points A thick filament consists of Answer Selected Answer: D. myosin. Question 2 1 out of 1 points Which of the following structures is most like an exoskeleton? Answer Selected Answer: E. a suit of armor Question 3 1 out of 1 points Which of the following structures constitutes part of the axial skeleton? Answer Selected Answer: C. skull Question 4 1 out of 1 points Which of the following attaches the forelimbs to the axial skeleton in
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a. number of muscle fibers. b. size of muscle fibers. c. number of striations. d. number of nuclei within the muscle fibers. e. number of muscle cells. 5. Actin myofilaments a. resemble bundles of minute golf clubs. b. contain both myosin and tropomyosin. c. are held in place by the M line. d. contain strands of fibrous actin. e. are the thickest proteins in muscle. 6. When an action potential reaches the presynaptic terminal‚ a. calcium ions diffuse into the presynaptic
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The Sliding Filament Theory In 1954‚ scientists published two groundbreaking papers describing the molecular basis of muscle contraction. These papers described the position of myosin and actin filaments at various stages of contraction in muscle fibers and proposed how this interaction produced contractile force. Using high-resolution microscopy‚ A. F. Huxley and R. Niedergerke (1954) and H. E. Huxley and J. Hanson (1954) observed changes in the sarcomeres as muscle tissue shortened. They observed
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depolarization of the cell membrane and this electrical signal travels along the muscle fibers. Through the movement of calcium ions‚ the muscle action potential is taken into actual muscle contraction with the interaction of two types of proteins‚ actin and myosin. Different steps of activities are involved in muscle contraction. The sequence of contraction process is originated in the central nervous system. It can be either a voluntary activity from the brain or a reflex activity from the spinal cord
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stroke_______________________. 2. The myosin head contains binding sites for what two molecules? a. ATP b. Actin 3. Three molecules make up the thin filament. a. Which molecule has a binding site for myosin heads? _Actin____________________________ b. Which molecule covers this binding site? _Tropomyosin________________________________________________ c. Which molecule has a binding site for calcium ions? _Troponin_____________________________________ 4. What molecule must bind to the myosin head in order for
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