human health

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HUMAN HEALTH

Outline the steps in contraction of a sarcomere (sliding filament theory

The shortening and elongation of the muscle fiber is referred to as muscle contraction . It is also known as twitch or muscle twitch . In general sense this contraction is processed by the CNS or central nervous system and it is composed of spinal cord and the brain According to the sliding filament theory contraction of a sarcomere takes place during the contraction of muscles . During this process the

I-band tends to shorten whereas there applies no change in the A-bands It has been found that the tropomyosin protein induces the muscle cell actin molecules by covering up the sites of the myosin binding . Here the tropomyosin becomes instrumental in the contraction of the muscle cell by uncovering the actin binding site . At this point protein tropomyosin yields troponin molecules that in turn bonds with Calcium ions thus actin is forced into binding of cross bridge . At this point sarcoplasmic reticulum controls the calcium contraction that is sited within the muscle cells . It should be noted in this case that the sarcoplasmic reticulum is basically an endoplasmic reticulum in a modified form After this stage the sarcomere pumps the calcium ions out of the cell and thereby puts an end to the process of Muscle contraction according to the sliding filament theory of contraction of a sarcomere

Explain why muscle contraction depends heavily on both good nutrition and good respiration

Good respiration is essential for the breaking down of the nutrition components into protein components . Protein on the other hand is instrumental in contraction of muscles . Therefore it is obvious that there is a good relation between sarcomere and good nutrition along with good respiration

There are quite a few actions of the protein in this context and one of the most important of these is the extension of I-band into A-band that is induced by Actin filaments . Moreover the Myosin filaments are found to be intermingled with A-band by the means of an overlapped formation and protein if found to be the main cause . Protein also forms a titin that combines with the filament of the sarcomere 's Z-line with the M-band . Here the combination with protein is responsible of forming thicker filaments . Incidentally , it could be mentioned that biggest protein is supposed to be the Titin . It is also believed to be helpful for a numerous protein binding process and acts as a rular of the sarcomere and is also instrumental in formation of combination and assembly in the context of sarcomere . It is also found that the stability of the sarcomere M-band and the Z-line are instrumented by the intervention of proteins . Furthermore , protein alpha-Actinin through Z-line and Z-disc acts as a cross link with Titin and Actin filament

Describe the structure of a single neuron

The structure of a single neuron is basically made up of three major parts . The first part is called soma this is the main body of the neuron . The second part is referred to as dendrites . Dendrites are small arms of the neuron that are used for reception of signals . There are hundreds of dendrites present in a neuron . They are also called arms The third part is composed of a longer arm that is basically used for sending the signals and is called axon . In one such axon there may be presence of numerous branches that are used for transferring signals into terminals that may sum up to be more than thousand

Reference

Roberts , O M (2005 Outline of Biology : The Methods and Practices with Illustrations National Book Trust

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