Well see neurotransmitters are pretty cool. They tell the body what to do. Your brain sends signals throughout your body using these. They're kinda like little cellphone towers, that call up your organs and tell it the plans for the night.
But why would a psychologist need to study that stuff?
Well psychologists study human behavior in short. They look at what makes people mad, why. What are signs. They study the not-so-physical parts of the human mind. The reason they need to know about the nervous system and neurons, and transmitters and such is because, this is how our body reacts to things around us. This is how the brain responds to things.
Like on the first day of school, you get that weird feeling in your stomach like "butterflies". You know you're nervous. Psychologists need to be able to recognize what causes this, and in order to understand it fully, they're going to need to know what the brain is telling your stomach to do on the first day of school, in response to how you feel about it.
It's kinda a little complicated to explain. But suffice to say, they need to know how the mind, and the body relate. The brain is the medium, like the translator. It takes things we see and hear, runs it through a system that compares it to things we've previously seen, heard, and experienced, and then we react to it. We may be scared, happy, depressed, anxious, or angry, or whatever. But if you don't experience it.... how would you ever know what you were. You're brain goes, ok she's angry, and tells your heart to speed up, and in turn increases blood pressure (which sometimes happens before we experience the emotion behind it). Judgment will be a little impaired, cause your brain will then be overcomplicating stuff.
See, psychologists have to be able to explain how a person displays a condition, behavior, emotion, and other psychological things. So they need to take a big interest in the brain and how it functions.
Hope this helps kiddo. Let me know if I can help you in the future.
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