I found the section about adrenaline fascinating. Something exciting happens outside of our body and our body reacts. First, the sympathetic nervous system ramps up and the parasympathetic system shuts down. Then, the sympathetic nervous system activates the adrenal glands and the fight or flight response is under way. These glands send armies of hormones into the bloodstream. One of these hormones, adrenaline, causes a terrific transformation in the body functions. Energy production in muscles skyrockets as fats are broken into fatty acids and glycogen into glucose. The heart muscle contracts, blood vessels constrict, and the bronchioles open up, all which help pump more oxygenated blood to the larger muscles in the body. In addition, the pupils open up and any sense of appetite disappears. This is amazing because our bodies are ready to run or fight for our lives.
I experienced this reaction when someone scares me. Blood seems to rush to my heart and I can feel it pounding away. Everything instantly comes into focus and all weariness is gone. My entire body becomes alert and I could easily run a mile if I had to.
One thing that I am curious about is the way that increased sympathetic nervous system activation affects a person. Does this mean the same as being stressed out all of the time? Could it contribute to high blood pressure and other problems? Is there a disease that causes people to have no adrenaline?
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