So the spoon looking thing in my diagram IS the neurone itself - the receptor here defects pressure, so when pressure is applied, it literally stretches open the sodium ion channels, causing Na+ influx, inducing the action potential. Then the rest is how a normal neurone to work - Na+ ions diffuse along the cytoplasm towards the next node of Ranvier, causing that point to reach the threshold potential, which then opens up the voltage-gated sodium ion channels, causing ion influx, generating AP etc.... This continues as saltatory conduction in myelinated neurones, which is how AP is propagated. Hope this makes sense! You can check my other videos on the topic for more info :)

@ thank you for your help, great videos too🙂

Yes that is correct :)

@@BioRach tysm for your reply!! I really appreciate it

Also I’m confused what does the dct do to the dilute filtrate that enters the dct from ascending limb

Good question! :) it could be either - if a new AP is generated, then that "first" sodium channel may not be voltage-gated. An example would be those found in the pacinian corpuscle, which the pressure applied literally stretch open the channels. If we're looking along a neurone where an AP is propagated (passed along), then they may be voltage-gated, meaning they open when they reach the threshold potential. Though in this case, they won't be considered as the "first" channels... In my video, I just referred to the "first" channel as the first one looked at in this particular section of the neurone, and it's not necessarily the first of the whole neurone (aka, the first one from the synapse). Hope this makes sense!

Sadly no... 😥

In the primary immune response, both processes are needed. Cell mediated response is how a macrophage turns into APC which activates T helper cells to trigger the subsequent immune response (such as the humoral response). Without this step, the humoral response of triggering B lymphocytes' antibody production would not occur, because it would mean no APC was made to activate T helper cells. Whereas for the secondary response, since memory cells are already made from the primary response, the immune system can therefore bypass the cell mediated response and go straight to humoral response of making specific antibodies. This is because the memory cells have the receptors to recognise the foreign antigens directly, without needing macrophages to alert them. Hope this makes sense! :)