...Muscular System The muscular system is made up muscles, joints, tendons, bones, ligaments and connective tissue that help to support the body’s internal organs. They work together to perform a variety of functions. These include; stability, posture, motion, heat, circulation and digestion within the body. Essentially the muscular system provides power for movement of all body parts. It is the muscles within our body which provide us with movement via contractions and without this vital system life would completely stop. Stability and posture Our skeletal muscles attach to our bones through tendons where bones act as levers. This causes our muscles to contract, relax, effectively it controls the bone. Muscles also provide strength for stability and posture by allowing the bones to align properly. If muscles are too tight or loose then this causes the bones to become misaligned which creates poor posture. Skeletal muscles can be stretched or strengthened to support the bone correctly, allowing maximal stability. Finally, skeletal muscles are also important for providing the body with balance and coordination which is also important because they aid fluid body movement for physical skill performance which is key when taking part in sport. Good balance and coordination also improves posture and prevents injury because you will have good postural responses to a stimulus e.g putting your hands in front of your face to protect yourself. http://www.childdevelopment.com.au/home/90 ...
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...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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...Muscle Contruction 2014 Assist. Prof. Dr. Yekbun Adıgüzel Istanbul Kemerburgaz University School of Medicine MED 121 Cell Tissue and Organ Systems I Biophysics Lecture Percentage Contributions of/in Muscles • Muscle composes 40 percent of body weight in adults, and 50 percent, in children • Muscle contains – 75 percent water – 20 percent protein – 5 percent organic and inorganic compounds • 40 percent of body is skeletal muscle • 10 percent of body is smooth and cardiac muscle CLASSIFICATION OF MUSCLES LOCATION http://biochem.umn.edu/muscle_lectures%5CLec13_Barnett2.pdf NEURAL CONTROL Voluntary ANATOMY OUTPUT TYPICAL ACTIVITY Normally relaxed Skeletal Attached to the skeleton High Cardiac Involuntary Heart High Rhythmically active Normally contracted Smooth Involuntary Viscera Low Modified from: http://www.physioweb.org/IMAGES/sk_musc_macro.jpg, http://www.physioweb.org/IMAGES/neur_musc_junc.jpg Spaces between the myofibrils are filled with intracellular fluid called From:http://users.rcn.com/jkimball.ma. sarcoplasm, containing large quantities of potassium, magnesium, ultranet/BiologyPages/S/sarcomere.png and phosphate, plus multiple protein enzymes. Also there are tremendous numbers of mitochondria… n Myofibril is composed of about 1500 adjacent thick (myosin) filaments and 3000 thin (actin) filaments, which are large polymerized protein molecules that are responsible for the actual muscle contraction...
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...contrast and explain the response of a single muscle fiber and a whole muscle to electrical stimulation - define the threshold stimulus and the all-or-none phenomenon. 2. Define a motor unit and describe how motor units are important in controlling the force and rate of muscle contraction. 3. Explain what is meant by recruitment of motor units. 4. Explain what is meant by muscle tone, and how it relates to posture and maintaining balance. 5. Explain the staircase effect. 6. Define tetanic contraction, and distinguish it from a twitch. 7. Distinguish between isotonic and isometric contractions, and give examples. 8. Describe the two ways in which smooth muscle is organized, and describe their functions. 9. Describe how the mechanism of smooth muscle contraction differs from that of skeletal muscle. 10. List four factors that control smooth muscle contractions. 11. Summarize in a table the similarities and differences between skeletal, smooth, and cardiac muscle. 12. Explain the ways in which different groups of skeletal muscles(agonists, etc.) interact to produce smooth, coordinated movements. ...
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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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...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 unit....
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...Cell Theory Cell Theory is a way to describe the biology of living things. Cell theory says that the cell is the basic unit of life. Cells by themselves are alive, but they can also be part of a larger living thing. The smallest living organisms (like bacteria but not viruses) and the biggest ones (like humans and whales) are all made of cells. Very small organisms like bacteria and amoebas are only made of one cell each, so they are called unicellular organisms ("uni" means "one"). Larger organisms are made of many cells, and they are called multicellular organisms. Definition: The Cell Theory is one of the basic principles of Biology. Credit for the formulation of this theory is given to German scientists Theodor Schwann, Matthias Schleiden, and Rudolph Virchow. The Cell Theory states: * All living organisms are composed of cells. They may be unicellular or multicellular. * The cell is the basic unit of life. * Cells arise from pre-existing cells. The modern version of the Cell Theory includes the ideas that: * Energy flow occurs within cells. * Heredity information (DNA) is passed on from cell to cell. * All cells have the same basic chemical composition. Animal Tissues 1. Epithelial: In Greek, ἐπί (epi) means "on" or "upon", and θηλή (thēlē) means "nipple". Epithelial layers are avascular, so they must receive nourishment via diffusion of substances from the underlying connective tissue, through the basement membrane. Epithelia...
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...Tissues in the body In biology, tissue is a cellular organizational level intervening between cells and a complete organ. A tissue is an ensemble of similar cells from the same origin that together carry out a specific function. Organs are then formed by the functional grouping together of multiple tissues. Epithelial Tissue Epithelial tissue covers the whole surface of the body. It is made up of cells closely packed and ranged in one or more layers. This tissue is specialized to form the covering or lining of all internal and external body surfaces. Epithelial cells are used for protection, absorption and secretion. Cell shapes found in epithelial tissue are squamous, cuboidal, columnar and transitional. Epithelial tissue is highly specialised for selective secretion and absorption of ions and molecules. Squamous: Squamous cells make up most of the cells in the outer layer of the skin. They have the appearance of thin, flat plates. Squamous cells form the lining of cavities such as the mouth, blood vessels, heart and lungs and make up the outer layer of the skin. Cuboidal: By lining the surface of various ducts of various glands and organs, simple cuboidal cells are able to provide a layer of protection from abrasion, foreign particles, invading bacteria and excessive water loss to the underlying tissue. In the kidney tubulus, the cells aid in the absorption and transport of filtered substances. Simple cuboidal consists of a single layer of cells with the same height...
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...014CRNA Interview Preparation Q: Tell me about a time when you had to manage a difficult clinical situation. Q: Tell me about a time when you were working with someone who wasn't pulling their weight, and they had a different value system than yours. How did you deal with this person? Q: Tell me about a time when you failed. What happened, and how did you recover? Q: Tell me about a time when you had an ethical dilemma at work. What did you do? Q: Tell me about a time when you felt it was you against everyone else. You thought you were right and that everyone else was wrong. What did you do? Q: Why do you want to be a CRNA?** Q: What would make you a successful CRNA?** Q: How do you handle stress? Q: What kind of patients do you take care of? Your favorite and why?** Q: Tell us about your work experience.** Q: How do you describe success? Q: Do you foresee any barriers to your education? (finances, time commitments) Q: What does a CRNA do? How do you think your role as a CVICU nurse relates to the role and responsibilities of a CRNA?** Q: Where do you want to be in 5 years?**. Q: Why our program? Q: What questions do you have for us?** A: What do you look for in potential students? How does your program facilitate student research? I am very interested in teaching and education, how does your program prepare me to be an educator? What do you see as your school's strong points? On avg. how many intubations, art lines...
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...to produce a contraction was .85. The proportion of fibres in the muscle that were contracting was only 10-20% of total fibres available. The nervous systems controls the amount of muscle fibres that contract. In this case only a small depolarization is causes and this was evident in the graph produced 4) The all or none law states that strength of muscle force will be the same at any stimuli strength if the stimuli strength is above the threshold of the muscle in question. The muscle will either respond fully or not respond at all, hence the name all or none. Once the minimum force threshold is met the muscle will respond, however below the minimum threshold no response will be visible. The muscle contraction is all based on the ability of channels to open. The more the channels open the stronger the depolarization event occurs. Responses to stimuli were graded on the strength of the contractions and the ability to create force. These forces were able to be compared to other forces throughout the experiments. EFFECTS OF STRETCH ON CONTRATION FORCE 1. The effect of stretching the muscle increases the contraction strength to a certain point until the muscle is over stretched. This was where our results stopped. This is known as the optimal length. However if we kept stretching the muscle over time it would of plateaued before decreasing. The muscle stretches to achieve an optimal length. If a muscle has not reached its optimal length less tension can be developed for...
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...Assignment 1 – (50 marks) Discuss the importance of body fluids and which one is considered to be the body’s internal environment. (4 marks) * Body fluids carry chemical communicators which organize actions amid cells, carry nutrients to cells, and carry waste products away from cells. They are the primary transport system between cells. The internal environment of the body is extracellular fluid, which refers to all of the fluids outside of our cells in our bodies – such as blood plasma, interstitial fluid, lymph and transcellular fluid. These fluids make up approximately 1/4 of body weight. Describe the three major types of lipids found in the body. (6 marks) * The three major types of lipids found in the body are triglycerides, phospholipids, and sterols (cholesterol). Triglycerides are fatty acids. Its functions include energy storage and the cushioning and insulating of the body and nerves. All nerves are wrapped in a myelin sheath; or lipid layer. Phospholipids are similar to triglycerides, but contain a phosphate group. It is a lipid bilayer – membranes in eukaryotic cells and the plasma membrane of cells. Sterols are made from lipids, but have no fatty acids in their structure. Cholesterol makes up sex hormones and carries lip-proteins. Describe briefly what is occurring at each step in the figure. (3 marks) * Name and briefly describe the cell shapes, arrangements, and functions of cell layers found in epithelial tissues. (3 marks) * In...
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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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...arteries in the body. Recently, some are being used as migraine preventers and powerful painkillers. In the body's tissues, the concentration of calcium ions outside of cells is thousands of times higher than the concentration inside of cells. Embedded in the membrane of some cells are calcium channels. When these cells receive a certain signal, the channels open, letting calcium rush into the cell. The resulting increase in intracellular calcium has different effects in different types of cells. Calcium channel blockers prevent or reduce the opening of these channels and thereby reduce these effects CCBs used as medications primarily have three effects: • By acting on smooth muscle they reduce contraction of the arteries and cause an increase in arterial diameter, known as vasodilation. • By acting on cardiac muscles (myocardium), they reduce the force of contraction of the heart • By slowing down the conduction of electrical activity within the heart, they slow down the heart beat. These effects cause an overall decrease in blood pressure, since it depends on the force of contraction and resistance of the arteries. However, these drugs are associated with several side-effects and prolonged use of them can lead to complications. Therefore CCB’s are usually are not used alone but are part of a combination of drugs used for the treatment. Side effects of these drugs may include but are not limited to:...
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...Skeletal muscle is one of the three major muscle types (besides cardiac and smooth muscle). They are a form of striated muscle tissue that is controlled by the somatic nervous system. Muscle fibers make up the individual components and are formed from the fusion of myoblast (the cells). Myofibers are multinucleated cells made up from the thin filaments called actin and thick filaments myosin myofibrils (long protein bundles) which are repeated as sarcomere, which act as the machinery for muscle contraction and gives it the striated appearance. Cardiac Muscle Smooth Muscle Skeletal Muscle The eukaryotic cell is composed of a numerous membrane bound organelles which work together to make a cell function based on the proteins expressed. These cellular components make the endomembrane system. Some of its major components are the Golgi apparatus which functions by modifying proteins and lipids. The cytoplasm is the fluid portion containing the organelles and the cytosol containing the cytoskeleton of the cell. The nuclei contain the genetic material, and functions by controlling gene expression and replicating and transcribing DNA. The endoplasmic reticulum is made up of the rough ER and the smooth ER and has several functions such as facilitates protein folding, protein transport, insertion of proteins, secretion of proteins, and calcium sequestration in the smooth ER. Calcium is the main regulation and signaling molecule in muscles. The...
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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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