Practice question · Multiple choice
A large meal makes you sleepy and a fright kills your appetite instantly. Why do digestion and alertness trade against each other so directly?
Hints
- Ask what a body escaping a predator needs, organ by organ, and what it can defer.
- One signal reconfigures many organs at once. That is the design, not a side effect.
Show the answer
B. Because the two branches bundle incompatible whole-body states
Why
The branches sell whole postures, not organ-by-organ settings: rest-and-digest commits blood to the gut, fight-or-flight yanks it to muscle. You cannot buy half of each, which is why a heavy lunch and a sharpened mind are in genuine competition.
Practise Peripheral Nervous System
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