Source: # Autonomic nervous system: two branches – the nervous system *From the book – Chapter 3: Human Brain and Nervous System* ## Autonomic nervous system: two branches #### Sympathetic nervous system (fight-or-flight) - Activates during stress or danger. - Increases heart rate. - Dilates pupils. - Redirects blood to muscles. - Prepares body for action. #### Parasympathetic nervous system (rest-and-digest) - Activates during rest. - Slows heart rate. - Promotes digestion. - Supports healing and recovery. - Conserves energy. The two branches work as a balance, not a light switch. The hypothalamus sits on the border of neural and hormonal control and aims the pituitary at the rest of the endocrine system — including the HPA stress axis and cortisol. Clinic note. Anxiety often feels like a sympathetic system that will not stand down. Depression and exhaustion often feel like a system that will not stand up. [Read the full chapter – Chapter 3: Human Brain and Nervous System](https://psychologyforeveryone.com/chapter/3/) ## Stories from real life - [The Alarm That Would Not Switch Off](https://psychologyforeveryone.com/story/the-alarm-that-would-not-switch-off-9/) – Priya was seventeen and preparing for her board exams in Jaipur. Whenever she opened her Physics paper, her heart hammered, her palms turned cold and wet,… - [After the Bike Fall](https://psychologyforeveryone.com/story/after-the-bike-fall-10/) – Arjun, twenty-two, rode his motorbike to a call centre in Hyderabad. One rainy night he skidded and hit his head. He had no helmet on. He… - [Learning to Paint at Seventy](https://psychologyforeveryone.com/story/learning-to-paint-at-seventy-11/) – Haridas, seventy-one, retired from the railways in Kolkata and found the days strangely empty. He began forgetting where he had put his glasses and worried that… - [Midnight Scrolling and the Growing Brain](https://psychologyforeveryone.com/story/midnight-scrolling-and-the-growing-brain-12/) – Fifteen-year-old Chloe lived in Manchester and was known at school for her sharp wit. Lately she had been dozing in class and saying things she regretted.… ## Shloks - [Katha Upanishad 1.3.3–4](https://psychologyforeveryone.com/shloka/katha-upanishad-1-3-3-4-14/) – Know the self as the rider, the body as the chariot, the intellect as the driver, and the mind as the reins. More on this topic: [The brain, hormones and body chemistry behind your moods](https://psychologyforeveryone.com/topic/brain-and-body/) ## More questions - [Parasympathetic nervous system (rest-and-digest) – the nervous system](https://psychologyforeveryone.com/answers/parasympathetic-nervous-system-rest-and-digest-the-nervous-system/) - [Understanding brain plasticity – the brain and nervous system](https://psychologyforeveryone.com/answers/understanding-brain-plasticity-the-brain-and-nervous-system/) - [Understanding messengers – the brain and nervous system](https://psychologyforeveryone.com/answers/understanding-messengers-the-brain-and-nervous-system/) - [Understanding taking care of your brain – the brain and nervous system](https://psychologyforeveryone.com/answers/understanding-taking-care-of-your-brain-the-brain-and-nervous-system/) - [Which brain region is mainly responsible for planning, decision-making and self-control?](https://psychologyforeveryone.com/answers/which-brain-region-is-mainly-responsible-for-planning-decision-making-and-self-c/) - [What is true: the limbic system is primarily involved in…?](https://psychologyforeveryone.com/answers/what-is-true-the-limbic-system-is-primarily-involved-in/) - [The "fight-or-flight" response is controlled by which part of the nervous system?](https://psychologyforeveryone.com/answers/the-fight-or-flight-response-is-controlled-by-which-part-of-the-nervous-system/) - [What is true: the occipital lobe is primarily responsible for…?](https://psychologyforeveryone.com/answers/what-is-true-the-occipital-lobe-is-primarily-responsible-for/) - [What is true: the brainstem controls…?](https://psychologyforeveryone.com/answers/what-is-true-the-brainstem-controls/) - [What does Katha Upanishad 1.3.3–4 mean for the mind? (Chapter 3)](https://psychologyforeveryone.com/answers/meaning-katha-upanishad-1-3-3-4/) [myadvisorfriend@gmail.com](mailto:myadvisorfriend@gmail.com) · [Contact](https://psychologyforeveryone.com/contact/) · [About](https://psychologyforeveryone.com/about/) · [Privacy](https://psychologyforeveryone.com/privacy/) · [Disclaimer](https://psychologyforeveryone.com/disclaimer/) --- *Psychology for Everyone – A Mental Well Being Series* by Satish Zope · free to read · Contact: [myadvisorfriend@gmail.com](mailto:myadvisorfriend@gmail.com) · [About](https://psychologyforeveryone.com/about/) · [Privacy](https://psychologyforeveryone.com/privacy/) · [Disclaimer](https://psychologyforeveryone.com/disclaimer/)