...1-Why do skeletal muscles enter in a contracted state called “rigor mortis” a few hours after death and last for up to 72 hours? Skeletal muscle enter a contracted state called rigor mortis because the skeletal muscles are only able to partly contract. The muscles are not able to relax, so the joints are fixed in place. Rigor mortis can be used to help estimate the time of an individual’s death. The onset of rigor mortis may range from ten minutes to several hours. Maximum stiffness is reached around 12-24 hours after death. 2-You are watching a football game and suddenly, a player falls to the ground without any other player touching or tackling him? Explain what happens and why? A football player falls to the ground without any other player touching or tackling him because he had a muscle cramp. Muscle cramps can happen without muscle injury. They are involuntarily and forcibly contracted muscle that does not relax. Muscle cramps can be due to poor blood cicculation in the legs, overexertion of the calf muscles while exercising, insufficient stretching before exercising, muscle fatigue, dehydration, or magnesium and potassium deficiency. 3-Every year in March, the LA Marathon gathers a big crowd and lots of participants. In the middle of the run, you notice that some players fall to the ground, although they Had a good start and seemed to be the favorites. Why did this happen and what is the explanation of this occurrence? Although they had...
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...Frog Skeletal Muscle S ta rted 2:10 p m Au g 4, 2014 Exercise 1: T witch Recruitment Using the Ho rizo ntal Co mpressio n butto ns and the scro ll bar, display the data yo u wish to include in yo ur repo rt. 1. As yo u increase vo ltage to the muscle describe ho w it respo nds to the increased stimulus. Answer St udy Quest ions 2. What was the smallest vo ltage required to pro duce a co ntractio n (the thresho ld vo ltage)? What pro po rtio n o f the fibers in the muscle do yo u think were co ntracting to pro duce this small respo nse? Answer 3. What was the smallest vo ltage required to pro duce the maximum (largest) co ntractio n? What pro po rtio n o f the fibers in the muscle do yo u think were co ntracting to pro duce this maximal respo nse? Answer 4. What do yo u co nclude happened to the number o f fibers co ntracting as the vo ltage was raised fro m thresho ld to that required to pro duce a maximal co ntractio n? Answer 5. In light o f the all o r no ne law o f muscle co ntractio n, ho w can yo u explain the graded respo nse? Answer Exercise 2: Effects of Stretch Using the Ho rizo ntal Co mpressio n butto ns and the scro ll bar, display the data yo u wish to include in yo ur repo rt. 6. Describe ho w the iso lated muscle behaved as it was stretched pro gressively. Answer St udy Quest ions 7. What effect do es stretching the muscle have o n co ntractio n strength? Is this effect linear? Answer 8. What stretch resulted in...
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...Glossary acetylcholinesterase: It is an enzyme that carries out the process of acetylcholine (a neurotransmitter) break-down at the region between two nerve cells (synaptic cleft) so that the impulse gets transmitted from one neuron to another. achalasia cardia: It is also called as cardiospasm and in this case the neuromuscular failure of oesophageal relaxation especially at the lower end with progressive dilatation of the part of the oesophagus above. actin-myosin crossbridging: It is responsible for the force generation and contraction of skeletal muscle. There are certain myosin-binding sites present on actin which undergoes bonding with myosin forming cross-bridges.it is an important step in skeletal muscle contraction. adenine: It is...
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...differentiating skeletal muscle cells Abstract Vitamin D deficiency can cause fat infiltration and this will lead to muscle 'quality' reduction. The probable mechanism of origin of these adipose cells is that abnormal trans-differentiation of myogenic precursor cells into adipocytes lead to the fat form within the intermuscular space. Myogenic precursor cells keep the potential to trans-differentiate towards the adipogenic lineage and VitD has potent effects on both adipogenesis and myogenesis. Therefore, the experiment is designed to investigate the effect of a broad range of concentrations of VitD3 active form (1,25(OH)2D3) on the capacity of the murine C2C12 muscle cell line to trans-differentiate towards the adipogenic lineages. C2C12 cells were cultured in adipogenic media and with increasing 1,25(OH)2D3 concentration (0, 10-13, 10-11, 10-9, 10-7 or 10-5M) for up to 6 days, the expression of muscle and fat gene markers were measured. The results showed that physiological concentration (10-13 and 10-11M) induces adipogenesis and myogenesis, while supraphysiological concentration (10-5M) inhibit both. (150) Introduction Nowadays, Vit D deficiency is considered as worldwide problem and influencing upwards of one billion people. Vit D deficiency can cause myopathy and atrophy of skeletal muscle (Holick 2006). Due to fat infiltration, there will be a concomitant reduction in muscle 'quality' (Ryall et al., 2008). The deficiency of Vit D is associated with skeletal muscle and Vit...
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...Youth Smoking Minerva Sanchez COH 435 National University May 26, 2015 Abstract Smoking is a health behavior that presents a burden of a preventable disease around the globe. Smoking and tobacco use, unhealthy diet, sedentary lifestyle contributes to over one million deaths annually in the U.S only. Although smoking prevalence in the U.S has dropped by half since the publication in 1964 on first Surgeon General’s Report on Smoking and Health, there is still increasing number premature deaths estimated at over 400,000 annually; the prevalence among the use of tobacco products in the younger populations is on the rise. Report by World Health Organization on the worldwide spread of tobacco use and smoking, it has warned on billion lives being lost by the end of the century. Identified as a significant source on premature mortality or death and preventable morbidity such as diseases and illness; cigarette smoking is one of the preventable behaviors that through the use of the media and public health legislation can effectively be eliminated. Introduction Health behavior can be termed as an activity undertaken with the essence of prevention or the detection of disease or towards improving the health and the well-being. The notion attached to the interest on the respective behaviors impact on everyone health and the well-being is attached on diverse assumptions. The assumptions are; a large proportion of the mortality...
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...Skeletal Muscle Hypertrophy , Chronic disease, disuse and aging are all causes of muscle atrophy. This fact directly impacts an individual’s ability to maintain an independent life-style. In contrast, stretching and work overload of skeletal muscle induces hypertrophy of skeletal muscle and myotubes in vivo and in vitro, respectively. Compensatory growth in response to an imposed load is an important and well-known biological adaptation of skeletal muscle. However, little is known about the systemic changes in hypertrophying muscle at the molecular level. Anabolic steroids, technically known as anabolic-androgenic steroids (AAS), are drugs that have similar effects to testosterone in the body. They increase protein within cells, especially in skeletal muscles. Anabolic steroids also have androgenic and virilizing properties, including the development and maintenance of masculine characteristics such as the growth of the vocal cords, testicles (primary sexual characteristics), and body hair (secondary sexual characteristics). Of the many 100’s of steroids which were never produced, it is from them that the supplement industry has selected our current roster of OTC anabolics. At this point you might be asking “How are these supplement companies able to legally manufacture and sell these products, since they are no different than any other CIII steroid?” Remember, it wasn’t until 1990 that steroids were officially declared to be controlled substances and illegal to possess without...
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... or any swelling, like round bulge over the joint. When the client opened his mouth maximally, vertical motion observed, with length of space about 5 cm between the upper and lower incisors. When the client partially opened his mouth and had lower jaw to protrude, moving side-to-side about 1.5 cm, and observed lower jaw protruding without any deviation. When the client clenched his teeth, observed left and right side equal in size, firmness, and strength. The client was able to fully resist the opposing force when resistance applied to moving jaw forward and laterally as well as to opening his mouth. Cervical spine: Observed client’s spine straight and head erect. Spinous process, sternomastoid, trapezius, and paravertebral muscles firm without muscle spasm or tenderness on palpitation. No asymmetry observed. The client able to perform without any pain with movement, including touching chin to chest, flexion about 45 dares, lifting the chin toward the ceiling, hyperextension about 55degrees, touching ach...
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...Broussard Exercise 2: Skeletal Muscle Physiology: Activity 2: The Effect of Stimulus Voltage on Skeletal Muscle Contraction Lab Report Pre-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. 1. Skeletal muscle fibers are innervated (stimulated) by You correctly answered: c. motor neurons. 2. A single action potential propagating down a motor axon results in You correctly answered: d. a single action potential and a single contractile event in the muscle fibers it innervates. 3. In resting skeletal muscle, calcium is stored in You correctly answered: c. the sarcoplasmic reticulum. 4. During the latent period for an isometric contraction You correctly answered: c. the cellular events involved in excitation-contraction coupling occur. 11/10/14 page 1 Experiment Results Predict Question: Predict Question: As the stimulus voltage is increased from 1.0 volt up to 10 volts, what will happen to the amount of active force generated with each stimulus? Your answer : c. The active force will first increase and then plateau at some maximal value as the stimulus voltage increases. Stop & Think Questions: What do you see in the active force display when the stimulus voltage is set to 0.0, and why does this observation make sense? You did not answer this question. Correct answer: a. 0.00 g; there was no activation of skeletal muscle fibers by this stimulus. What is the lowest stimulus voltage that induces active force in the skeletal muscle? You did not answer...
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...Introduction: Motor neurons and muscle fibers are the building blocks of motor units and where they intersect is called the neuromuscular junciton. The region where the flattened end of a motor neuron transmits neural impulses to a muscle is the motor end-plate. The end plate potentials depolarizes skeletal muscle fibers caused by neurotransmitters binding to the postsynaptic membrane in the neuromuscular junction. The process of contraction of the muscle cell is called excitation-contraction coupling. In this experiment, when we used a single electrical stimulus, it resulted in a muscle twitch with three phases: latent period, contraction phase, and the relaxation phase. Activity 1: Figure 1: Identifying the latent period ]The Latent Period of time that elapses between the generation of an action potential in a muscle cell and the start of muscle contraction. The length of the latent period was 2.78msec. When we increased the stimulus voltage from 3v to 9v and then to 10v, the latent period remained the same at 2.78msec. Thus, the latent period does not change with different stimulus. Activity 2: Figure 2: Identifying the Threshold Voltage The threshold is the minimal stimulus needed to cause a depolarization of the muscle plasma membrane. It is the point at which sodium ions start to move into the cell for membrane depolarization. When we stimulated the voltage of 0, the active force showed a straight line such as depicted in figure 2. We kept on increasing the...
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...nerve cells in the brain and the spinal cord. Motor neurons reach from the brain to the spinal cord and from the spinal cord to the muscles throughout the body. The progressive degeneration of the motor neurons in ALS eventually leads to their death. When the motor neurons die, the ability of the brain to initiate and control muscle movement is lost. With voluntary muscle action progressively affected, patients in the later stages of the disease may become totally paralyzed. A-myo-trophic comes from the Greek language. "A" means no or negative. "Myo" refers to muscle, and "Trophic" means nourishment–"No muscle nourishment." When a muscle has no nourishment, it "atrophies" or wastes away. "Lateral" identifies the areas in a person's spinal cord where portions of the nerve cells that signal and control the muscles are located. As this area degenerates it leads to scarring or hardening ("sclerosis") in the region. As motor neurons degenerate, they can no longer send impulses to the muscle fibers that normally result in muscle movement. Early symptoms of ALS often include increasing muscle weakness, especially involving the arms and legs, speech, swallowing or breathing. When muscles no longer receive the messages from the motor neurons that they require to function, the muscles begin to atrophy (become smaller). Limbs begin to look "thinner" as muscle tissue atrophies. ALS is commonly referred to as Lou Gehrig’s disease. Lou Gehrig was the one of the greatest baseball players...
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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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...BIOL 2010 LEARNING OBJECTIVES 1. 1.1. 1.2. 1.3. 1.4. 1.5. 1.6. 1.7. 2. 2.1. 2.2. 2.3. 2.4. 2.5. 2.6. 2.7. 2.8. 2.9. 2.10. 2.11. 2.12. 2.13. 2.14. 2.15. 2.16. 2.17. 2.18. 2.19. 2.20. 2.21. Describe the physical organization of the human body and explain how interaction between body components is critical for the maintenance of homeostasis. Define the terms anatomy and physiology in reference to the human body. (LECT & LAB) Describe each of the following levels of organization of the human body: chemical, cellular, tissue, system, organism. (LECT & LAB) Identify the principal systems of the body. (LECT & LAB) Describe the standard anatomical position of the human body. (LECT & LAB) Compare common anatomical terms used to describe the various regions of the human body. (LECT & LAB) List by name and location the principal body cavities. (LECT & LAB) Define homeostasis and explain the effects of the lack of homeostasis on the body's function. (LECT & LAB) Describe the chemical level of organization of the human body. Describe the interrelationship of matter, elements, and atoms. (LECT) Identify by name and symbol the principal elements of the human body. (LECT) Diagram and label the structure of a typical atom. (LECT) Describe the function of electrons located in incomplete outer energy levels. (LECT) Define the terms isotope and radioisotope and give their functions. (LECT) Describe the three types of chemical bonding (ionic...
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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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...domestic pig is the main reservoir host for T. spiralis. This species is significantly higher in prevalence in people living in certain parts of Europe, Asia, and Southeast Asia than in the United States. It is now considered endemic in Japan and China. A large outbreak of trichinellosis occurred in Lebanon in 1997, infecting over 200 people.5 Trichinella spiralis infection in humans has been reported from Korea for the first time.6 In contrast, trichinella infections in wildlife within the United States are now thought to be largely due to the T5 strain, tentatively designated T. murrelli.7 Life Cycle Infection is initiated by ingesting raw or undercooked meats harboring the Nurse cell-larva complex (Fig. 21.1). Larvae are released from muscle tissue by digestive enzymes in the stomach, and then locate to the upper two-thirds of the small intestine. The outermost cuticular layer (epicuticle)...
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...Biol. 2250 Question 10. A contracting skeletal muscle fiber decreases in length as thick and thin protein filaments within sarcomeres interact to cause sarcomeres to shorten. Tension is exerted on the portions of the skeleton where the muscle is attached to cause movement in the body. The first physiologic event of skeletal muscle contraction is muscle fiber excitation by a motor neuron. A nerve signal is propagated down a motor axon and triggers the entry of Ca+ into the synaptic knob. Ca+ binds to proteins in synaptic vesicle membrane. Calcium binding triggers synaptic vesicles to merge with the synaptic knob plasma membrane and ACh is exocytose dint the synaptic cleft. ACh diffuses across the fluid filled synaptic cleft in the motor end plate to bind with ACh receptors. The second physiologic event of muscle contraction is excitation-contraction coupling an event that involves the sarcolemma, T-tubules, and sarcoplasmic reticulum. Binding of ACh to ACh receptors in the motor end plate triggers the opening of these chemically gated ion channels. Na+ rapidly diffuses into and K+ slowly diffuses out of the muscle fiber. The result is a reversal in the electrical charge difference across the membrane of a muscle fiber at the motor end plate, which is called an end plate potential. An action potential is propagated along the sarcolemma and T-tubules. First voltage gated Na+ channels open and Na+ moves in to cause depolarization. Second voltage gated K+ channels open and...
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