Tonic Muscles

These muscles are under control of will. These muscles are controlled by the central nervous system. i.e. Coraco brachialis muscle. This is found in the upper part of the arm and flexes the shoulder joint.

The body has many amazing systems within it. The muscular system is on of the systems that is the most intriguing. Type I, Type IIa, and Type IIb comprise the muscular fiber types within the human body. Type I or Slow-twitch fibers contain mitochondria. These mitochondria use the oxygen that is taken in to create adenosine triphosphate (ATP). ATP fuels muscle contraction. Type I fiber is considered to be aerobic due to the use of oxygen. The slow-twitch muscle fibers are also known as red fibers. This alias is due to the dark red appearance cause by the amount of myoglobin within the fiber. Slow-twitch fibers are the first within the body to be activated due to having a lower activation threshold. They create their own energy source which allows these fibers to sustain force for a longer period of time. The negative aspect is they are unable to create a large amount of force. If the fibers are unable to generate the amount of force that is needed then the fast-twitch fibers will be activated.

Chapter 13 talks about the muscular system and the way that it is works together with the skeletal system and other systems in our body. It also explains the ways our muscles contract and move and what processes are going on in within our muscles when we work each one of them. The chapter also talks about disorders that can happen within our muscles and the way they affect our life. What I found most surprising in the chapter was reading the box that talked about botox ad wrinkles. It was shocking to read that the toxin used for botox is one of the most lethal substances and yet people are voluntarily putting it in their body. Another thing that surprised me to know was that the same substance had also been approved to treat migraine headaches.

The mouse should be next to the keyboard so that when you use the mouse your shoulder and upper arm is as near the relaxed vertical position as possible. i.e. do not keep your arm in a stretch position.

The popliteus muscle is a minor flexor of the knee. It penetrates the joint capsule to find its origin on the lateral condyle of the femur, and passes obliquely to insert on the medio-proximal tibia. Its main function is to help stabilize the knee, but is also able to rotate the femur on the tibia to unlock the knee.

Isometric contractions appear when there is no change in the length of the contracting muscle. This occurs when carrying an item in front of you. As the weight of the item is pulling your arms down, but your muscles are contracting to hold the items at the same level. Isokinetic contractions are really similar to isotonic, in that the muscle changes length during the contraction. Where they are different is that Isokinetic contractions produce movements of a constant speed. What you need to measure this is something called a isokinetic dynamometer. Concentric contractions are those which cause the muscle to shorten. An example is bending the elbow from straight to fully extended, causing a concentric contraction of the Bicep muscle. Eccentric

Due to a more sedentary than out primal ancestors, our muscles can get out of alignment by doing (literally) nothing. Without jobs the way they are, our muscles are likely to experience a pattern overload. This is when the same muscle groups get activated, with the same workload, over and over again. The problem is that these repeated movements offset our natural movements and cause problems for our bodies. You may find it becoming increasingly more difficult to pick something up from the floor or to simply get out of your chair. These repeated movements set off a chain reaction of events that can negatively alter your mobility and posture.

The second type of movement in the muscles are antagonist. Antagonist muscles compete with a specific movement. This controls a motion, slows it down, and returns a limb to its original position. Antagonism is not an essential property; it is a role that a muscle plays depending on the motion. If a motion is reversed, agonist and antagonist muscles switch roles. Because a flexor muscle is always a flexor, in flexion it is the agonist, and in extension it is the antagonist. On the other hand, an extensor muscle is the agonist in extension and the antagonist in flexion. Using the example above of the triceps brachii during a push-up, the elbow flexor muscles are the antagonists during both the up phase and down phase of the movement. The last

Muscles origin are always connected to the immovable bone, on the other side, the intersection is connected to the movable bone. Movement of the body occurs when muscles contract across joints and their attachments move toward the origin. Movements that are called Angular can increase or decrease the angle between the bones. Flexion can decrease the angle of the joint and can make the articulating bone come closer, an example could be nodding you head. An extension is the opposite and can make the angle larger.

DHP (dihydropyridine) receptors in t-tubule are all potential targets in muscle fiber. An action potential would not be able to be fired if there is curare blocking the ACh-receptor channels since the receptors for ACh will be blocked, thus there would be no change in the chemicals and the muscle fiber will not experience anything. If the calcium-binding sites in troponin-C is blocked by curare, then calcium signals will not be sent and will not trigger the myosin heads for a power stroke and the process for contraction of the muscle fiber to not occur since there is not initiation. Finally, DHP channels in t-tubule is the middle channel between motor endplate ACh receptors and DHP receptors in t-tubule. The ACh from motor end plate will cause an action potential and thus when it is blocked with curare, there will be no release of calcium from the sarcoplasmic reticulum since the t-tubule is blocked, there will be no conformation change of DHP to initiate the opening of RyR channels. If the concentrations of all the chemicals involved--calcium, sodium, and potassium--are known initially, then the resulting concentrations will indicate which was bounded by curare. For example, if potassium levels are greater than that of sodium, then an action potential was

The elbow is one of the more complex joints in the body given its ability to withstand the many external forces that it encounters. One of the most common complaints today amongst the office working population is lateral epicondylitis which due to prolonged periods of sitting at their desks in front of computers.

One particular section of the articulatory system that I found fascinating deals with the tongue muscles. The hypoglossal nerve innervates most of the tongue muscles with the exception of the palatoglossal muscle. The tongue appears to be one structure, but as it turns out, it contains up to eight muscles. The eight muscles are then subdivided into two groups: intrinsic and extrinsic.

ction of the muscle is caused by the excitement of muscle spindles whenthe muscle is stretched. This is known as the stretch (myotatic) reflex. The monosynapticpathway causes only a slight delay between the muscle stretching reflex and the reflexcontraction. There are no interneurons. The spindles and sensory afferent nerves, from thespindles, synapse directly with motor neurons. The pathway that is created constitutes shortestpossible reflex

(Shrivastava & Bhopate, 2012). The most common overuse injury associated with computer use is Carpel Tunnel syndrome (Ali & Sathiyasekaran, 2006). The musculo-skeletal problems are significantly related to the number of working hours. Computer vision syndrome and musculoskeletal problems are increasing among software professionals globally. To reduce vision and musculo-skeletal morbidities, interventions should focus on redesigning and improving workstation ergonomics (Shrivastava & Bhopate, 2012).

Moreover, staying in just one position for a long period ( sitting in a chair with a bright computer screen right in front of you) can make you more susceptible to neck, back, and shoulder pain. All these can even affect your performance and inadvertently limit the progress of the company.