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Explain the sliding filament model of muscular contraction

The presence of calcium ions causes tropnonin to detach from tropomyosin-this exposes the mysoin head binding sites. Myosin head groups attach to the surrounding actin filaments forming a cross bridge. The h...
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Answered by Karishma D. • Biology tutor
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Describe how the cardiac cycle is coordinated with reference to the sinoatrial node (SAN), the atrioventricular node (AVN), and Purkinje tissue.

The SAN is the pacemaker, situated at the top of the right atrium. The SAN initiates a wave of excitation at regular intervals. The wave of excitation quickly travels over the walls of both atria. As it pass...
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Answered by Karishma D. • Biology tutor
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Define homeostasis and explain it in the context of blood glucose concentration.

Homeostasis is the maintenance of an constant internal environment around a strict set of parameters . Homeostasis is important to maintain optimal conditions for biochemical reactions within the body, espec...
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Answered by Jake S. • Biology tutor
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How should I revise?

First of all it is important to have clear and useful notes to revise from. Keep your school notes organised and you can write your own notes while looking back over these online sessions. I personally found...
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Answered by Sarah B. • Biology tutor
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What is negative feedback and what is positive feedback? Give an example for each of where it is important in regulation?

Negative feedback : occurs where the feedback causes the corrective measures to be "switched off", and in doing so returns the system to its original level. Example: Temperature regulation in mamma...
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Answered by Sarah B. • Biology tutor
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