Which part of the autonomic nervous system conserves energy as it slows the heart rate?

The parasympathetic part of the autonomic nervous system is primarily responsible for conserving energy and promoting a state of rest and digest within the body. This system counteracts the effects of the sympathetic nervous system, which is responsible for the 'fight-or-flight' response. When the parasympathetic nervous system is activated, it induces a decrease in heart rate by releasing the neurotransmitter acetylcholine, which acts on the heart's pacemaker cells to slow down their activity.

In addition to lowering heart rate, the parasympathetic system facilitates digestion, promotes glandular activity, and encourages various functions that enhance energy conservation. This is essential for maintaining homeostasis within the body and allowing it to recover and repair after stress or activity.