Learning fascinating stuff.
- Each time there is an action potential, the concentration gradient of ions is disturbed, ie; the sodium ions diffuse in and potassium diffuses out (which is not really good if you want to maintain the ‘normal’ concentration gradients of these ions across the membrane and the normal resting potential). Hence, after each action potential, the sodium potassium pump works to pump out the sodium ions and pump in potassium ions to reset their concentration gradients using ATP which actually produces heat just like any other machine! And this heat can be measured, which can tell us information about the extent of ‘activity’ in a nerve. The more frequent the impulse, the more heat produced.
- Unlike most muscles, the resting membrane potential of cardiac muscles is around -65 mv instead of -90 mv, due to which the heart muscles show self-induced discharge (ie; it is myogenic). The process of why this happens is there in the book, but like most things in physiology it’s way too long to explain.
- Local anesthesia works by acting on voltage gated sodium ion gates, making it difficult for them to open during action potential (effectively increasing the threshold voltage). Hence, with the right dose of anesthesia, this threshold voltage can be raised to high that no impulse is enough to cause action potential and so there is no conduction of nerve impulse. And the patient feels no pain ; )
- Each molecule of actin (the muscle fibril protein) has an ADP (adenosine di-phosphate) molecule attached. The heads of myosin are actually attracted to ADP it seems, which forms the basis for muscle contraction. Had not learnt this detail in A levels lol.
- In fact, as I went through the book, the author admits that scientist still do not much about the different steps involved in muscle contraction and how it works (even after all these years of research). Hence, so much of what we study are actually just hypotheses! But we still take them so seriously lol. Science is weird.
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