What part of the nervous system is responsible for slowing down breathing and pulse?

• A. Sympathetic
• B. Central
• C. Peripheral
• D. Parasympathetic

Answer: (D)

Parasympathetic division of the autonomic nervous system. This branch promotes rest and digestion, dialing back activities that use energy. It slows the heart by releasing acetylcholine onto muscarinic receptors in the sinoatrial node, reducing the rate of natural pacemaker firing and lowering the pulse. It also influences the lungs, where acetylcholine causes some bronchoconstriction and a calmer, slower breathing pattern. In contrast, the sympathetic division speeds up heart rate and respiration for a “fight or flight” response, so the parasympathetic system is the one that slows these functions.