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One of the most amazing things about the human body is the incredible range of movement and mobility it has. This day to day activity is accomplished by our muscles through the extraordinary and facinating ability of converting chemical energy, energy stored in nutrients, into mechanical energy, energy of movement. Muscles are often viewd as the "machines" of the body. They help move food from one organ to another, and carry out our physical movement. There are three diffrent kinds of muscles in our body: cardiac, smooth, skeletal.
Cardiac
Cardiac muscles are involuntary and found only in the heart. They are controlled by the lower section of the brain called the medulla oblungata, which controlls involuntary action throughout your body. Think about how horrible it would be to have to consciously tell your heart to beat, with the consequence of forgetting being death. What about when you went to sleep!?! But luckily enough, the medulla oblungata does all that for us.
Your heart cells come in long strips, each containing a single nucleus, one of the key factors in determining which of the three classes any particular muscle is. Located at the walls of the heart, its main function is to propel blood into circulation. Contraction of the cardiac tissue is caused by an impuse sent from the medulla oblungata to the SA nerve located at the right atrium.
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Smooth
Your smooth muscles, like your cardiovascular muscles, are involuntary. They make up your internal organs, such as your stomach, throat, small intestine, and all the others, except your heart.Unlike cardiovascular muscles, smooth muscles are generally spherical, as most other human cells are, and each contains one nucleus.
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Skeletal
The skeletal muscles are the only voluntary muscles of your body, and make up what we call the muscular system. They are all the muscles that move you bones and show external movement.Back to the top.
Unlike either of the other two classes, skeletal muscles contain multiple nuclei because of its large size, being in strips up to a couple of feet long.
The muscles we have in our body are divided into three classes of muscles: cardiac, smooth, and skeletal. Usually, when we think of muscular system we often only remember the skeletal muscles because they make up what is recognized as the muscular system. The muscular system, composed of over 600 muscles, come in a variety of shapes and forms. Diffrences between each muscle are recognized by location, function, structure, and the way they are contracted.
Muscle-Bone interactions - Lever System
A lever is a rigid bar on which a given load is moved with supporting help from a fulcrum. A fulcrum is a fixedpoint on which lever can move in diffrent ways or angles. The whole muscular system interacts in this kind of way with the skeletal system. Given a load the muscles pull the bone up or in any direction againsrt the load. Your joints usualy seem to be the fulcrum on which you move the lever or bone. For example, try lifting a book with your hand and puting your elbow on the table. You can move the book in any direction with the help of the joints in your elbow, and the book is lifted in any direction due to the muscles contractions.
Skeletal muscles can be broken down into groups based upon the type of movement they portray. The movement of the muscle is based upon the type of joint upon which the muscle works. Skeletal muscles can't expand, or make themselves longer, but they can contract, or make themselves shorter, so they generally work in pairs. One contracts, and in doing so stretches the other, and reverses its effects on the joint. For example, when you contract your major arm muscle, which is called the bicep, in return the lower arm muscle, called the tricep, extends. So as you contract one muscle the other one extends. These effects can be broken down into groups of their own: flexors, extensors, adductors, and abductors. Flexors and extensors become plantarflexors and dorsiflexors, respectively, when located within either the wrist or ankle joints.
Flexors
Flexors bend at the joint, decreasing the interior angle of the joint. The bracius humorous, or bicep, is a flexor of the elbow joint, bringing the fist towards the shoulder. If a flexor appears in either the wrist or ankle joints, it becomes a plantarflexor.
Extendors
Opposites of flexors, extensors unbend at the joint, increasing the interior angle. The humorous, or tricep, is an extensor of the elbow joint, taking the fist farther away from the shoulder. If an extensor is found in the wrist or ankle joints, it becomes a dorsiflexor.
Abductors
Abductors take away from the body, like lifting the arm to the side. Abd- means to take away, like abduct and abdicate. Spreading out your fingers uses abductors, because you are taking away your fingers from an imaginary line running down your arm.
Adductors
Adductors, the opposites of abductors, move toward the body. Add- means to increase or include. By lowing an arm raised to the side, or moving your fingers together while keeping them straight, your muscles are adducting.Back to the top.
Tendons and Ligaments
As fascinating as they are, muscles alone can't do the job. At every joint, tendons and ligaments also help out. Muscles wouldn't be very useful alone because they don't directly connect to the bone, so even if they contract, they wouldn't be moving anything. Instead, muscles are connected to tendons, when themselves are connected to the bones. When the muscles contract, they pull on the tendons, which in turn pull on the muscles, and that causes movement.
But without ligaments, that movement wouldn't be too useful because it would not be directed movement. Without ligaments, instead of bones bending or rotating about each other when muscles contract, they would slide by each other. Ligaments are what hold the bones together. They connect at the ends of muscles and keep them from slipping and sliding, and force them to bend.
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Major Skeletal Muscles
The muscual body is divide into ten diffren areas where muscles can be found: facial, neck, shoulder, arm, forearm, thorax, abdomen, hip, pelvis/thigh, leg.
Facial
In the facial are one finds all the muscles wich move the face. Orbicularis oculi are the two muscles that move the eye are. Frontalis and Temporalis are the two muscles which move the forehead and sides of your head. Zygomaticus ands Masseter are the two muscle that work in conjunction to move tyoou jaw and upper lip area. Orbicularis oris is the muscle which moves your lips.
Neck
The neck area is almost entirely moved by the sternohyoid and Sternocleidomastoid. These muscles allowthe neck to move your head left and right. They work with the platysma muscle to control how far you can move your head left and right. What allows your head to move up and down is the trapezius. The trapezius is so large that it extend down to the shoulder and thorax area. The trapezius is a good example of how some muscles are named by their shape. the trapezius looks just like a trapezoid.
Shoulder
A group of muscles all work together to move the whole shoulder area. This group takes into account the trapezius, deltoid, infraspinatus, teres major, and the rhomboid major. The rhomboid major is called so because its shaped like the geometric shape of a rhombus. Along with the help of the ball and socket joint in your shouder, these gruop of muscles allow your arm to throw a softball, pick things over your head, and give your arms a good strech early in the morning.
Arm
Most known amongst teenage weight lifters is the arm area. The famous bicep brachii is the muscle that allows you to bring your forearm close to your body and form a huge ball of muscle wich catches a lot of attention amongst weight lifters. The tricep brachii and brachialis are the two other muscles located in the arm region. These muscles allow a person to do push-ups!
Forearm
A majority of the muscle in the forearm help control a part of the arm. Amongst these is the Berachiodialis major, palmaris longus, and Flexor carpi radialis. The name of the flexor carpi radialis is a good example of how muscles are named by their function and location. This muscle is named carpi because of the bones that it helps move, the carples. Also, the name of radialis is made by the bone that its attached to, the radius.Back to the top.
Thorax
The thorax is the set of muscles which carrying your head, arms, stomach, and any other upper body areas. These muscles are the trapezius and latissimus dorsi. Usually, the majority of the muscles of the thorax can be damaged easly is one dose not streach before excersice, or lifts a heave load.
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Abdomen
The abdominal area consists of the muscles that allows you to bend down and move your waist from side to side. The interanl oblique and external oblique are the muscles that move your body from left to right. The Transversus abdominus and Rectus abdominus, along with the trapezius an latissimus dorsi allow you to bend down and grab objects.
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Hip
Only two muscles make up the hip area. These are the gluteus medius and gluteus maximus. Probably the laziest muscles in the whole system the gluteus set of muscles are used only to sit down on.
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Pelvis/Thigh
An overlaping of muscles is what makes this area so firm. The pelvis area is usualy refered to as the upper part of the leg. Muscles like the pectineus and illiopsoas , which help support the upper leg area are known as pelvic muscles. Thigh muscles are very rich in capillaries and support the whole body. The upper thigh muscles are abductor longus, Gracilis, Sartorius, and Tensor fasciae latea. The lower thigh muscles are rectus femoris, vastus lateralis and medialis. Located in the back of your leg are the hamstrings. These muscles help you run, jump, and walk!
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Leg
Helping the thigh region support the body is the Leg region. These muscles like the Gastrocnemius, soleus, porenius longus, and Tibialis anterior absorb the impact when one walks and runs. they also give beter cordination for moving. the thigh region trust the body forward while the leg region coordinates where it should be thrusted and where it should stand.
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