Why Do Muscles Contract?

Smooth muscle contraction occurs when calcium is present in the smooth muscle cell and binds onto calmodulin to activate myosin light chain kinase (Wilson et al., 2002). Phosphorylation of myosin light chains result in myosin ATPase activity thus cross-bridge cycling occurs causing the muscle to contract (Horowitz et al., 1996). There are two known models of excitation and contraction in smooth muscle, electromechanical coupling (EMC) and pharmomechanical coupling

As a result of the contractions in the Muscle- Skeletal Longitudinal Section cells and the Muscle- Skeletal Cross Section cells, it allows your muscle to be able to contract in response to nerve stimuli. This means that the movements of most of these muscles are not involuntary, you can control them. Therefore, once the stimulation stops, the muscles relax.

The Purpose of this exercise is to understand how muscle twitch, contract and react to different activities.

types of muscle tissues : skeletal, cardiac, smooth. Each of these different tissues has the ability

Muscle contraction starts with an electrical "go" signal from your brain. It stimulates the SR to open its calcium gates, flooding the myofilaments with calcium. The rise in calcium concentration causes the myofilaments to alter form and abbreviate. The coincidental shortening of myofilaments give rise to contraction.

Muscles use electricity to contract. Cells engender a voltage difference by altering the concentration of ions (Sodium and Potassium) called electrolytes. Theses electrolytes are additionally referred to as salts. Without the ions there is no cellular potential difference. The electrical signal activates what are called cross bridges by sanctioning Calcium to contact the thin filament of the sarcomere, this is where the ATP comes in. Cross bridges are minuscule golf club like proteins that are on the cessation of the thick filaments of the sarcomere. ATP is bound to the ATPase domain of the cross bridge. When ATP is hydrolyzed (makes ADP and Phosphate) it changes conformation (which designates shape) and affixes to the actin portion of the

There are several steps that are needed to complete muscle contraction. First a neuron action potential arrives at the end of the motor neuron. Acetylcholine (ACh) is later released from the axon to receptors, which is located on the sarcolemma. The sarcolemma is stimulated and a muscle impulse travels over the surface of the muscle fiber and deep into the fiber through the transverse tubules and reaches the sarcoplasmic reticulum

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Most of the stories in this tale have someone being turned into an animal, talking animals, or some type of importance placed on animals. This shows that the societies these tales were written in had strong beliefs towards animals; along with this idea comes the heavy implications of god in each tale. Each tale has some mention of god or at the very least a phrase very similar to “by god” or something involving “god”. Furthering this idea of divine or spiritual influences comes in the forms of demons, which are widely available throughout the story. Lastly, the tales in this story seem to all suggest a male dominated lifestyle, with most stories having the man as the most important. All this in mind suggest that the stories reflect a society

The muscles produce more energy as skeletal movements increase when you do this test as they would for any type of exercise, and the circulatory system's activity during exercise enhances the supply of fluids, oxygen and nutrients your muscles need for energy production. The circulatory system plays a strong part in helping your body to balance and maintain healthy chemical strengths during exercise. Your circulatory system's veins work harder circulating waste-rich blood back to your heart during exercise and pumps faster so your heart contracts and pushes the blood into the pulmonary artery; and your lungs absorb carbon dioxide from the pulmonary artery and expel the toxic gas from your body each time you exhale. The Capillary beds in your

Muscles contract when the central nervous system gets a signal to contract from the brain. In order to know how muscles contract you have to know what elements create a muscle. The skeletal muscles are made up of many bundles of muscle fibers, which are long strands of multinucleate cells. The fiber is formed by the fusion of many cells. The muscle fiber’s main components are the myofibrils. The myofibrils contain sarcomeres, which is the main element responsible for the contraction and relaxation of the muscle. The contraction and relaxation actually are from the sarcomere shortening and lengthening. The sarcomere is made of thick filaments made of myosin and thin filaments composed of actin. These filaments never change in length; in fact, they slide past each other, which then allows the sarcomere to shorten the muscle to contract. In actual contraction, there is an interaction between myosin heads and the actin filament. In this interaction, a group of proteins aid in the process. Those proteins are, troponin and tropomyosin and the proteins actin and myosin that have been mentioned early that are contractile proteins (Johnson 2013).

As muscles can only pull they must work together to as antagonistic pairs, this is where one muscle contracts and shorten (Concentric) while the other relaxes and lengthens (eccentric) in other to allow the movement to occur, this is known as an isotonic contraction. The voltotary muscles are also capable of an isometric contraction this is where the muscle/s are contacting but no movement is occurring for example in a ski sit or Rugby scum. Muscles are also able to undergo an Isokinetic contraction where by the muscles contract and shorten at a constant speed.

Isometric muscle is a contraction without no movement to the joint. This occurs regularly in gymnastics and yoga. When a isometric contraction takes place the muscle doesn’t lengthen or get shorter. This sort of muscle contraction is used to strengthen muscles with out causing stress on joints.

Contractility is an ability to shorten a muscle with force and acuteness when stimulated. Contractions are responsible for all body movement this helps to keep the body alive. When the muscle contracts they design different strengths of movement. There are four different types of contractions. The isotonic contraction is when force is generated by the changing the length of muscle. A concentric contraction is when a movement causes the muscle to shorten by generating force. An eccentric contraction is when the muscle causes itself to elongate in return to a greater opposing force. An isometric contraction is when the muscle generates force without changing the length of your muscle. All of these allow a human to move their eyes, participate

A muscle contraction has 4 stages, muscle activation, muscle contraction, recharging and relaxation. For a muscle contraction to occur there must be a Neural stimulus, which is a hormone also known as adrenaline, that is released by the endocrine gland. There has to be calcium in the cells, which is a chemical element found in many foods, and there must be ATP there for energy.