The three different types of muscle tissue that exist in a human body are cardiac, smooth, and skeletal. Cardiac muscle is an involuntary muscle that is only present in the heart. It has responsibilities such as pumping blood throughout an entire body’s circulatory system. Smooth muscle is also an involuntary muscle. It is found in the trachea, intestines, and bladder; therefore, it has responsibilities such as slowly contracting and relaxing pressure on its surrounding organs. Lastly, skeletal muscle is a voluntary muscle tissue that assists in movement. It is located where bones and tendons are connected. Most organs in a human body are surrounded by skeletal muscle.
A skeletal muscle is composed of many muscle fibers that allow it to contract when exposed to a stimulus. If enough skeletal muscle fibers are present and able to sense the stimulus, this will cause muscle contraction of the entire muscle. However, if not all the muscle fibers are able to sense the stimulus, a small muscle twitch will occur with a weak stimulus. A muscle twitch is when a muscle has the ability to relax and contract quickly, it occurs when there is a single, quick electrical stimulus that still causes a short contraction. The strength of the muscle contraction correlates to the amount of individual muscle fibers responding to the stimulus.
There are many factors that can affect the threshold stimulation of a muscle. The purpose of this lab was to determine if the workload amount applied on various frog muscles had a corresponding relationship to an increasing stimulation. The muscles workload shows how much a particular muscle can bear, while the threshold stimulation shows weakest electrical stimulation that causes the muscle to twitch. The point...
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... affected the data table. Not going in 0.5 intervals for every muscle at every workload would conclude to inaccurate data if not all electrical stimuluses’ were tested.
In conclusion, this lab was performed to see if various electrical stimulations and workload weights had an effect on different types frog muscles. This lab is crucial to real world applications because muscles are present in every living organism – and mainly beneficial to humans. There are many different types of muscles containing a range of functions that are crucial to movement in the human body that we use from day to day. Doing this lab informed people that the greater number of muscle fibers a muscle contains that responses to a stimulus will lead to a greater strength of contraction. This lab showed which muscles are the most important to movement and why muscle twitch/contractions occur.
In the beginning phases of muscle contraction, a “cocked” motor neuron in the spinal cord is activated to form a neuromuscular junction with each muscle fiber when it begins branching out to each cell. An action potential is passed down the nerve, releasing calcium, which simultaneously stimulates the release of acetylcholine onto the sarcolemma. As long as calcium and ATP are present, the contraction will continue. Acetylcholine then initiates the resting potential’s change under the motor end plate, stimulates the action potential, and passes along both directions on the surface of the muscle fiber. Sodium ions rush into the cell through the open channels to depolarize the sarcolemma. The depolarization spreads. The potassium channels open while the sodium channels close off, which repolarizes the entire cell. The action potential is dispersed throughout the cell through the transverse tubule, causing the sarcoplasmic reticulum to release
The data collected during this experiment has shown that a relationship likely exists between the rate of muscle fatigue and the time spent performing vigorous exercise prior to the set of repetitive movements. This is likely due to a build-up of lactic acid and lactate as a result of anaerobic respiration occurring to provide energy for the muscle cell’s movement. As the pH of the cell would have been lowered, the enzymes necessary in the reactions would likely not be working in their optimum pH range, slowing the respiration reactions and providing an explanation to why the average number of repetitions decreased as the prior amount of exercise increased.
The data was recorded for ten minutes. The last segment in the data collection was to analyze the effects of direct electrical stimulation. The hook electrode was disconnected and two electrode needles were inserted about five mm from each end of the gastrocnemius muscle. Starting at the maximum voltage from the first experiment, voltage was slowly increased until a twitch appeared. Then voltage was set to ten times the maximum voltage from the first experiment.
The subject was then asked to perform the same steps as last week in addition to getting their blood lactate taken before activity begins and again at every increase in incline. These processes were performed the following week as well, but the test subject was given a concoction that contained 250 mg of caffeine. This study was a double blind study in which the instructors, nor the subjects knew when the test subject was given caffeine. By having a double blind study all biases for how the data should turn out were eliminated. In addition, the professors, the test subject, and the research group were unable to skew the data because they were unaware of when the subject got the
Every day we use our skeletal muscle to do simple task and without skeletal muscles, we will not be able to do anything. Szent-Gyorgyi (2011) muscle tissue contraction in rabbit’s muscles and discovered that ATP is a source for muscle contraction and not ADP. He proposed a mechanism to cellular respiration and was later used by Sir Hans Krebs to investigate the steps to glucose catabolism to make ATP. In this paper, I will be discussing the structure of muscle fibers and skeletal muscles, muscle contraction, biomechanics, and how glucose and fat are metabolized in the skeletal muscles.
This report will explore the structure and function of skeletal muscle within the human body. There are three muscle classifications: smooth (looks smooth), cardiac (looks striated) and skeletal (looks striated). Smooth muscle is found within blood vessels, the gut and the intestines; it assists the movement of substances by contracting and relaxing, this is an involuntary effort. The heart is composed of cardiac muscle, which contracts rhythmically nonstop for the entire duration of a person’s life and again is an involuntary movement of the body. The main focus of this report is on skeletal muscle and the movement produced which is inflicted by conscious thought unless there is a potentially harmful stimulus and then reaction is due to reflex, as the body naturally wants to protect itself. Skeletal muscle is found attached to bones and when they contract and relax they produce movement, there is a specific process that the muscle fibers go through to allow this to occur.
As we have learned through our reading, most all bodies skeletal muscles are made up of primarily three types of skeletal muscle fibers, but their proportion differs depending on what action the muscles is doing. For example, type I fibers such as muscles of the neck, back, and leg have a higher proportion. According to Quinn (2014), type I muscles are slower and more effective, they tend fire a lot slower than fast twitch fibers and they fatigue at a much slower rate. Hence, slower twitch fibers are pronounced at helping athletes run marathons and bicycle for hours. Shoulder and arm muscles are not always active but are intermittent in their use; these muscles tend to have a larger amount of tension for uses in throwing and lifting. These muscles have a combination of both type I and type II B fibers. These fast twitch fibers use anaerobic metabolism to create energy and are the "classic" fast twitch muscle fibers that excel at producing quick, powerful bursts of speed. These muscles are used in events such as 100m sprint, basketball, soccer and football. Since this muscle fiber fires at such a high rate of contraction it will fatigue much faster and will not last long before needing to rest.
Skeletal, smooth, and cardiac muscles play a vital role in the everyday processes that allow the human body to function. Without these muscles, everyday tasks and functions could not be conducted. Injury to these muscles could cause serious problems, however, these muscles have the ability to regenerate, repair, and fix multiple problems all by themselves. Repair and regeneration of a muscle are two similar, yet different things. Repair restores muscle continuity so that it can continue to function in the same way as before injury, but does not completely restore the pre-injury structure like regeneration (Huijbregts, 2001). Muscle repair and regeneration take place after an injury, after surgery, after atrophy, and even after working out.
Cardiac muscle is a type of involuntary muscle found only in the walls of the heart, specifically the myocardium. Cardiac muscles contract automatically to tighten the walls of the heart in a rhythmic fashion. The heart beats nonstop about 100,000 times each day. Smooth muscle is a type of involuntary muscle found within the walls of blood vessels such as in small arteries and veins. Smooth muscle is also found in the urinary bladder, uterus, male and female reproductive tracts, gastrointestinal tract, and the respiratory tract. Skeletal muscles are voluntarily controlled and are attached to bones by tendons. Skeletal muscles also vary considerably in size and shape. They range from extremely tiny strands such as in the muscle of the middle ear as large like in the muscles of the thigh. The three individual muscle types also serve five main functions. The five basic functions are movement, organ protection, pumping blood, aiding digestion, and ensuring blood flow.
During testing, most patients are found to need correction in all 14 balance tests, depending on the ailment the patient complains of and how well they react to the muscle correction will tell whether or not further treatment is needed. The physical aspect of the therapy, despite the name and basic principles, is not the only aspect required for optimal results. One must also report lifestyle and diet changes ranging from daily stress levels to pat...
Sarcopenia is considered to be the degenerative loss of skeletal muscle mass and it’s functioning due to aging (Waters, Baumgartner & Garry 2000). It is linked to muscle atrophy which is shortening of the muscle. It can be mostly noticed in fast twitch fibres which usually fatigue easily and provide a larger amount of force in comparison to slow twitch fibres. Sarcopenia is usually ...
Muscle activity, including generating force and moving limbs through lengthening and shortening, is an important influence on beneficial tissue stress. Muscles adapt quickly to periods of lower or higher stress and demonstrate obvious visual and functional changes. At a tissue level, the Physical Stress Theory (PST) states that muscle adaptations are consistent with other high and low strain tissue adaptation models. Low stress/activity associated with immobilization results in decreases in contractile protein, fiber diameter, peak tension and power. Evidence supports the idea that tissues within the musculoskeletal system atrophy and become less tolerant of physical stress if stress on the tissue diminishes below a baseline level.3 In addition,
When observing both cell types under a microscope several differences are obvious. Firstly, skeletal muscles are larger than smooth muscle cells (one muscle cell can be up to 100µm in length). They are also multinucleated whilst smooth muscle cells are uninucleate (Alberts et al, 2002: 961). Additionally, skeletal muscle cells appear to be striated, whereas smooth muscle cells do not show this banding pattern; but are instead smooth and tapered. The absence of this patterning in smooth muscle cells suggests that they consist of a less organised collection of contractile fibres (Silverthorn, 2007: 397). This banding pattern in skeletal muscles is known as the sarcomere.
use it or would the effect be lower? Another suggestion is to include a statement discussing test method variation and the impact (or lack of impact) on the test results. Finally, a larger sample size can help determine if borderline data is significant. While cost is almost always a consideration in research, the text discusses changes in muscle metabolism as not detectable. Additional data from more test subjects could produce results with statistical significance.
The contraction of a muscle is a complex process, requiring several molecules including ATP and Cl-, and certain regulatory mechanisms [1]. Myosin is motor protein that converts chemical bond energy from ATP into mechanical energy of motion [1]. Muscle contraction is also regulated by the amount of action potentials that the muscle receives [2]. A greater number of actions potentials are required to elicit more muscles fibers to contract thus increasing the contraction strength [2]. Studied indicate that the larger motor units, which were recruited at higher threshold forces, tended to have shorter contraction times than the smaller units [3]. The aims of the experiment were to reinforce the concept that many chemicals are required for skeletal muscle contraction to occur by using the rabbit muscle (Lepus curpaeums) [2]. In addition, the experiment was an opportunity to measure the strength of contraction and to observe the number of motor units that need to be recruited to maintain a constant force as the muscles begin to fatigue [2]. Hypothetically, the rabbit muscle fiber should contract most with ATP and salt solution; and the amount of motor units involved would increase with a decreasing level of force applied until fatigue stage is reached.