Impact of hormones or other things on feelings.

I understand the model (thoughts cause feelings that drive behaviour), but I wanted to ask about those feelings or reactions that seem ingrained in us as human beings. For example, a mother’s love for her child – it is just her thoughts about that child that makes her feel love or is it something more? Also the idea of our mood being affected by the seasons – is feeling ‘low’ in the winter just a case of our thoughts or is there something else involved? I guess both of those examples might have some sort of biological/hormonal element going on – just wondering how you deal with that sort of thing when you’re self-coaching or coaching others. Maybe’s it’s not helpful to focus on those things, but just the things we can control, i.e. our thoughts?