...INTRODUCTION: The skeletal muscle is an important organ in the human body that allows for movement and support of the skeleton, helping the body execute various tasks from precise control movements (writing a letter or picking up a chalk) to more abrupt, powerful movements (lifting weights or running). The skeletal muscle is one of the main types of muscle in the body (the other two being cardiac and smooth muscles) that allows movement by contraction of the muscles. When a motor unit, a single nerve that innervates all the muscle fibers, activates these muscles fiber, it causes a muscle contraction. These muscle contraction occurs when motor neurons from the spinal cord leaves and activates multiple muscle fibers, the number of muscle fibers depend on the type of muscle. According to the Hennemen size principle, muscles that react rapidly and exert fine control have smaller motor units than those with larger, weight-involving muscles, whose movements are less precise, will require larger motor units. The means of movement and force generation is based on the skeletal muscles contraction. Contractile units of the skeletal muscles include thick myosin and thin actin myofillaments or fillaments. Sarcomere is the smallest contractile unit of a muscle fiber. The repetition of the sarcomere structure make up myofibrils and hundreds to thousands of these myofibrils make up a single muscle fiber (Sherwood 258). Contraction is initiated by an increased in the intracellular calcium...
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...Lab Dr. Xu 2 March 2016 Frog Skeletal Muscle Lab Introduction A biologist by the name Jan Swammerdam performed the first experiments on muscle physiology between 1661 and 1665. Swammerdam demonstrated that an isolated frog muscle can contract if the sciatic nerve is irritated with a metal object. Almost a century later, a physician by the name Luigi Galvani demonstrated that frog muscle responds to electrical currents. In the late 1840s, either Carlo Matteucci or Carl Ludwig attributed to the invention of the kymograph, which is illustrated as a rotating drum powered by a clockwork motor. The invention of the kymograph changed experimental physiology by allowing muscle contractions, and other actions, to be recorded and analyzed for the first time ever. Muscle cells, or muscle fibers, are defined as the basic unit of a muscle. Therefore, complete muscles are constructed from bundles of muscle fibers, but there are no gap junctions between adjacent cells so each fiber performs independently. Myofibrils establish an ordered structure for single muscle fibers. Every myofibril is comprised of actin and myosin. Actin and myosin are contractile proteins that can slide past each other when Ca2+ and ATP are present. A motor unit is described as a single motor neuron and all of its innervating muscle fibers. Like nerve tissue, muscle fibers produce an all-or-none response to a stimulus, generating a twitch. A single motor neuron supplies numerous muscle fibers to make up a motor...
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...Virtual Lab: Muscle Stimulation Post-Lab Quiz and Lab Report Table I: Threshold Stimulus (V) |Load |Lower Forelimb Muscle |Upper Forelimb Muscle |Calf Muscle |Thigh Muscle | |0g |2.5 |3.0 |5.0 |6.0 | |5g |3.0 |4.0 |5.5 |6.5 | |10g |4.0 |5.0 |6.0 |7.0 | |20g |7.0 |7.0 |7.0 |8.0 | |40g |8.0 |8.0 |8.0 |9.0 | |80g |9.0 |9.0 |9.0 |10.0 | All green highlighted values sklhuld be 0 or none. The muscles have stopped responding because they are fatigued. (-12) Post-laboratory Questions: 1. Smooth muscle: C a. Is voluntary b. Is found in the heart c. Is found in lining the intestines d. All of the above 2. Skeletal muscle: B a. Is involuntary b. Is made up of muscle fibers c. Is attached to bone via ligaments d. All of the above ...
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...Quarterly Journal of Experimental Physiology (1986) 71, 467-473 Printed in Great Britain FREE INTRACELLULAR MAGNESIUM CONCENTRATION IN FERRET VENTRICULAR MUSCLE MEASURED WITH ION SELECTIVE MICRO-ELECTRODES L. A. BLATTER AND JOHN A. S. McGUIGAN Department of Physiology, University of Berne, Buehlplatz 5, 3012 Berne, Switzerland (RECEIVED FOR PUBLICATION 2 AUGUST 1985) SUMMARY The free Mg concentration ([Mg]i) was measured in ferret ventricular muscle using singlebarrelled Mg-sensitive micro-electrodes. The electrodes were calibrated in solutions containing the [K]i and [Na]i measured in this tissue. In thirteen measurements from seven experiments conforming to strict criteria for calibration and penetration the estimated mean [Mg]i was 04 mmol/l. This is to be regarded as an upper limit since it was estimated by linear extrapolation of the calibration curve. INTRODUCTION Ionized Mg plays an essential role in the regulation of a large number of cellular functions. It is a co-factor in many enzymatic reactions, influences tension development in muscle and modulates amongst others the ionic transport systems in mitochondria (see reviews by Gunther, 1977; Shine, 1979; and Ackerman & Nicholls, 1983). Despite its importance in cellular mechanisms, estimations of the free Mg ([Mg]i) by various methods range from 0- 1 mmol/l to 6 mmol/l (reviews: Flatman, 1984; Gupta, Gupta & Moore, 1984) mainly because of the lack of a simple direct method for its measurement. Direct measurement of...
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...Frog Skeletal Muscle Exercise 1: Twitch Recruitment Using the Horizontal Compression buttons and the scroll bar, display the data you wish to include in your report. 1. As you increase voltage to the muscle describe how it responds to the increased stimulus. A n s w e r A n s w e r Study Questions 2. What was the smallest voltage required to produce a contraction (the threshold voltage)? What proportion of the fibers in the muscle do you think were contracting to produce this small response? A n s w e r A n s w e r 3. What was the smallest voltage required to produce the maximum (largest) contraction? What proportion of the fibers in the muscle do you think were contracting to produce this maximal response? A n s w e r A n s w e r 4. What do you conclude happened to the number of fibers contracting as the voltage was raised from threshold to that required to produce a maximal contraction? A n s w e r A n s w e r 5. In light of the all or none law of muscle contraction, how can you explain the graded response? A n s w e r A n s w e r Exercise 2: Effects of Stretch 6. Describe how the isolated muscle behaved as it was stretched progressively. A n s w e r A n s w e r Study Questions 7. What effect does stretching the muscle have on contraction strength? Is this effect linear? A n s w e r A n s w e r 8. What stretch resulted in the highest contraction...
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...Portfolio Task: Module 3 (546 Words) “Give a detailed description of the theory that explains how a muscle fibre shortens” Sliding-Filament Theory proposes that a muscle shortens or lengthens because the thick and thin myofilaments sliding past each other without filament lengths being affected. Thus, muscle, fibre, and myofibrils change lengths, but not myofilaments. Processes of muscle contraction: First Stage: The first stage is when the impulse gets to the unit. The impulse travels along the axon and enters the muslcle through the neuromuscular junction. This causes full two to regulate and calcium channels in the axon membrane to the open. Calcium ions come from extra cellular fluid and move into the axon terminal causing synaptic vessels to fuse with pre synaptic membranes. This causes the release of acetylcholine (a substance that works as a transmitter) within the synaptic cleft. As acetylcholine is released it defuses across the gap and attaches itself to the receptors along the sarcolemma and spreads along the muscle fiber. Second stage: The second stage is for the impulse spreads along the sarcolemma. The action potential spreads quickly along the sarcolemma once it has been generated. This action continues to move deep inside the muscle fiber down to the T tubules and the action potential triggers the release of calcium ions from the sacroplasmic reticulum. Third Stage: During the thrd stage calcium is released from the sacroplasmic reticulum and actin...
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...anatomy/physiology of muscle contraction. Anatomy of Skeletal Muscle: A single skeletal muscle, such as the triceps muscle, is attached at its • Origin to a large area of bone; in this case, the humerus. • At its other end, the insertion, it tapers into a glistening white tendon which, in this case, it’s attached to the ulna, one of the bones of the lower arm. As the triceps contracts, the insertion are pulled toward the origin and the arm is straightened or extended at the elbow. Thus the triceps is an extensor. Because skeletal muscle exerts force only when it contracts, a second muscle a flexor is needed to flex or bend the joint. The biceps muscle is the flexor of the lower arm. Together, the biceps and triceps make up an antagonistic pair of muscles. Similar pairs, working antagonistically across other joints, provide for almost all the movement of the skeleton. The Muscle Fiber Skeletal muscle is made up of thousands of cylindrical muscle fibers often running all the way from origin to insertion. The fibers are bound together by connective tissue through which run blood vessels and nerves. Each muscle fibers contains: • An array of myofibrils that are stacked lengthwise and run the entire length of the fiber; • Mitochondria; • An extensive smooth endoplasmic reticulum (SER) • Many nuclei (thus each skeletal muscle fiber is a syncytium). The multiple nuclei arise from the fact that each muscle fiber develops from the...
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...BBE 517 - ERGONOMICS FOR CONSTRUCTION MAMAGEMENT CLASS ASSIGNMENT THE HUMANCAPABILITY AND LIMITATIONS IN LIFTING MATERIALS AT ACONSTRUCTION SITE 17TH NOVEMBER 2014 HUMAN LIFTING CAPABILITY AND LIMITATION ON CONSTRUCTION SITES 1.0 Introduction Ergonomics is the science and art of fitting the job to the workers. There are numerous activities that take place on site that enable realization of the structure being constructed. Generally construction involves the utilization of materials in undertaking the works. This will involve labour of the workers to put in place the materials as per the design are it mixing, lifting and placing them in place, installation, delivery and storage of the materials. Material handling can be by machines/equipment or directly by the workers themselves. Handling and storing materials involves many different activities such as hoisting, manually carrying bags or material and stacking supplies. Employees can be injured by improperly lifting materials (manually and by machine), falling objects and improperly stacked supplies. This paper concentrates on the human ability in the movement and placement of materials and other facilities as work progresses on site. An examination of activities on an active site have been undertaken to inform this paper on the practicability and applicability of researched theories relating to human lifting capability on site. The following sites have been examined and findings discussed later in this...
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...| Chapter 8 Muscular System | |The Muscles: Each muscle is an organ, comprised of skeletal __muscle__ tissue, several ___connective____ tissue coverings, __nervous_ tissue to cause it | |to contract, and __blood___ to nourish it. | | Connective Tissue coverings: | |The muscle has several dense connective coverings. | |Layers of dense connective tissue, called __fascia___, surround and separate each muscle. | |This connective tissue extends beyond the ends of the muscle and gives rise to cord like | |__tendons___ that are fused to the periosteum of bones. | |Sometimes muscles are connected to each other by broad sheets of connective tissue called | |___aponeuroses___ ...
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...disorder that causes a hypermetabolic state after administration of volatile anesthetics. When a patient is under anesthesia, the muscles are usually relaxed, but when a patient is experiencing Malignant Hyperthermia crisis, certain IV anesthesia causes the opposite effect. Most inhaled anesthetics other than nitrous oxide, cause or trigger Malignant Hyperthermia. More specifically, the anesthetic agents: Halothane, Chloroform, and Succinylcholine. The genic condition of Malignant Hyperthermia only becomes apparent when a patient is exposed to certain anesthetics such as halothane, which causes muscle rigidity. During the relaxed phase of muscle contraction, adenosine triphosphate and phosphate (ADP and Pi) are bound to the myosin S1 fragment, which is in a strained vertical position. Depolarization to the sarcoplasmic reticulum occurs followed by the depolarization of the triad region which initiates the release of calcium into the cytosol. This calcium then binds to troponin. A conformational change in the actin-tropomyosin interaction is induced by the troponin-calcium complex, which allows myosin to bind to actin. The binding allows the S1 to move to the unstrained position, causing muscle contraction. During this process, ADP and Pi are released. The muscle contraction results from the shortening of every sarcomere in every muscle fiber of the motor units that is recruited. ATP, if available, then binds to the S1. The ATP is then broken down to ADP and Pi...
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...1. Muscle spindles - Provide sensory information about changes in muscle length and tension of muscle fibres - They primarily respond to any stretch of a muscle and, through reflex response, initiate a stronger muscle action to reduce the stretch - Two sensory afferent fibres and one motor efferent fibre services the spindle 2. Golgi Tendon Organs - Golgi tendon organ connects up to 25 extrafusual fibres near the tendon’s junction to the muscle - Golgi tendon organs discharge impulses under two conditions: - 1: in response to tension created in the muscle when it shortens - 2: in response to tension when muscle is stretched passively - When stimulated the Golgi receptors conduct their signals rapidly into the spinal cord to elicit reflex inhibition of the muscles they supply -...
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...human body. Attached to the bones of the skeletal system are about 700 named muscles that make up roughly half of a person’s body weight. Each of these muscles is a discrete organ constructed of skeletal muscle tissue, blood vessels, tendons, and nerves. Muscle tissue is also found inside of the heart, digestive organs, and blood vessels. In these organs, muscles serve to move substances throughout the body.... Muscular System Anatomy Muscle Types There are three types of muscle tissue: Visceral, cardiac, and skeletal. 1. Visceral Muscle. Visceral muscle is found inside of organs like the stomach, intestines, and blood vessels. The weakest of all muscle tissues, visceral muscle makes organs contract to move substances through the organ. Because visceral muscle is controlled by the unconscious part of the brain, it is known as involuntary muscle—it cannot be directly controlled by the conscious mind. The term “smooth muscle” is often used to describe visceral muscle because it has a very smooth, uniform appearance when viewed under a microscope. This smooth appearance starkly contrasts with the banded appearance of cardiac and skeletal muscles. 2. Cardiac Muscle. Found only in the heart, cardiac muscle is responsible for pumping blood throughout the body. Cardiac muscle tissue cannot be controlled consciously, so it is an involuntary muscle. While hormones and signals from the brain adjust the rate of contraction, cardiac muscle stimulates itself to contract. The natural...
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...Describe the following tissue types: Epithelial - Epithelial tissue covers the entire surface of the body. It is made up of cells nearly pressed and extended in one or more layers. This tissue is specific to structure the covering or coating of all inward and outer body surfaces. Epithelial tissue that happens on surfaces on the inside of the body is known as endothelium. Epithelial cells are packed firmly together, with practically no intercellular spaces and just a little measure of intercellular substance. Epithelial tissue is generally divided from the underlying tissue by a meagre sheet of connective tissue; cellar layer. The basement membrane gives structural backing to the epithelium furthermore ties it to neighbouring structures. Epithelial tissue can be divided into two groups depending on the number of layers of which it is creates. Epithelial tissue which is stand out cell thick is known as basic epithelium. On the off chance that it is two or more cells thick, for example, the skin, it is known as stratified epithelium. There are also nerve supplies to the epithelia but they are supplied with oxygen and nutrients from deeper tissues by diffusion. There are three types of epithelial tissue, which include cuboidal, columnar and squamous Simple cuboidal epithelia are a type of epithelium that refers to a single layer of cube-like cells. These cuboidal cells have large, spherical and central nuclei. The cells of this sort of tissue can withstand more trauma than basic...
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...diseases much faster than they have been able to in the past. This could potentially help cure those who are diagnosed. My second reason is that biomedical technology can increase treatment options. Since mammograms and MRIs help detect diseases sooner there are many different ways to treat these diseases some of which may not be as severe. For example instead of doing radiation for cancer right away you could undergo surgery to try to remove the cancer first. My third reason is that new medical practices can be discovered by using biomedical technology. Stem cells, mammograms, MRIs, and genetic engineering are all biomedical technologies. The discovery of stem cells have made an advancement in the medical world because they can turn into muscle cells, skin cells, and many other cells. Mammograms have made it...
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...is a rare, multisystemic progressive, debilitating, and often fatal neuromuscular disorder. Pompe Disease is linked to a deficiency of the lysosomal enzyme, acid alpha-glucosidase (GAA), which is responsible for the breakdown of glycogen (a stored form of sugar that the body uses for energy) inside of the cells. Without GAA present there is an intralysomal accumulation of glycogen in the muscle cells which leads to a loss of muscle function (Pompe Community, 2014). According to the National Institute of Neurological Disorders and Stroke, Pompe Disease affects all muscle cells in the body but skeletal muscle and cardiac muscle are most seriously affected (NINDS, 2013, February 20). According to the Pompe Community, when there is a continuous accumulation of glycogen it causes lysosomes to swell and eventually rupture, which causes the tissue damage (Pompe Community, 2014). Signs and Symptoms According to the Pompe Community, Pompe Disease can set in at any age and progresses differently in every case. Infants who are affected by Pompe Disease often appear “floppy” and have extreme muscle weakness. They may develop milestones such as sitting, rolling over, and talking...
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