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Kiran Dhaliwal Anatomy Lab 1. Skeletal muscle is just another form of striated muscle tissue. The muscle fibers are cylindrical, long, and multinucleated cells. The muscle fibers consist of actin and myosin myofibrils. The human body consists of three major muscles, one of them being skeletal muscle. They are movable and they also support the skeleton. This muscle links two bones across the bones connecting joint. When skeletal muscles contract or shorten the bone it is linked to moves. These muscles are consciously controlled by us. This muscle is made to relax or contract by voluntary control. Skeletal muscle has a very smooth texture. This muscle is strong and stretchable for support and to allow us to be moveable. On the other hand ligaments are fibrous tissues. The function of these tissues is to prevent contact of the bones or the cartilage. In other words the tissues prevent bones and the cartilage from rubbing against each other which can be very painful. They are short bands of very tough but flexible connective tissue. They help to certify alignment of the bones and are composed of collagen fibers. They prevent abnormal movements of the bones aside from preventing contact. Ligaments are hard and strong, extensible but very difficult to break. Ligaments are white with a woven texture. Skeletal muscle and ligaments have similar purposes which include preventing abnormal movement, keeping joints in place, and movement in general. 2. Hypertrophy refers to excessive growth. More generally it is the abnormal enlargement of a part or organ in the body. The abnormal enlargement occurs from the increase in muscle cells. An example would be cardiac Hypertrophy which is the thickening of the heart muscle and typically occurs in the bottom chambers of the heart, known as the ventricles either being the right or left. Cardiac Hypertrophy occurs from increased stress on the heart. Atrophy is the decrease in size or wasting away from the body, part or organ. More specifically failure of growth. The cause of atrophy is nerve damage or defective nutrition. An example of Atrophy includes pathological atrophy which occurs in muscles due to motor nerve diseases, or muscle tissue diseases. 3. Isotonic exercise is when opposing muscles contract and the movement is controlled. The tension is constant while the muscle lengths are changing. An example of an isotonic exercise would be lifting free weights. The isotonic muscle contraction is what helps strengthen or tone muscles and improve joint mobility in the body. Isometric exercise is a muscle building exercise. This type of exercise includes muscular contractions against resistance but without any movement. In other words the muscles contract leaving the length of the muscles the same and unchanged. Isometric exercise is used to strengthen many different muscles in the body by pushing two parts of the Kiran Dhaliwal body against each other (two hands) or against an object. This way the muscles become strongly stressed and are only stretched slightly, and this produces strength in the muscles which helps maintain toned muscles. An example of isometric exercise would be the plank which can be used to improve strength of the abdominal muscle. In order to perform the plank start lying flat on the floor, raise body off of ground using toes and forearms, keeping the back flat, and the abdominal muscles firm. 4. In order to prevent injury to the back muscle from lifting a heavy load a worker should follow the following steps: Test the load before lifting to determine how heavy the load is, make sure the weight is balanced and won’t become unbalanced when lifting, grip the object tightly before lifting, and use a ladder when you’re lifting something from over your head or if below then do not arch your back but instead do the work with your arms and legs. The best way to lift a heavy load is by using slow and smooth movements, keep your body facing the load while lifting or keep load close to your body, lifting with your legs can be done if you are able to straddle the load (bend your knees not your back, keep your back straight not bent), and try to carry the load between your shoulder and waist space which puts less strain on your back. 5. Professional baseball pitchers have one arm which is more muscular than the other mainly because that one arm is used more often to pitch the ball. The constant use of this arm helps strengthen muscles in the arm leading it to appear more muscular than the other. In order to pitch the ball, the player steps backwards with the opposite leg of whichever hand is used to pitch, then the hip is slightly rotated so that he/she is towards the catcher, then the arm is extended and the ball is thrown with great force and strength. While the player turns to face the catcher rotation occurs since the hips are rotated to the forward position. Flexion also occurs since the two muscles are being brought closer together (brachioradialis the elbow flexor, and biceps). At the ball release flexion occurs when the elbow is flexed ready for the ball to be thrown, extension also occurs when the arm is extended to release the ball. Rotation in the deltoids and arm occurs when the arm begins rotating forward to generate speed. Plantar flexion occurs when the leg is moved from the back to get into the forward position and dorsiflexion also occurs at this time. Abduction is also occurring when the pitcher has his/her arm rotated in a full circle.
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