NEET BIOLOGY

Detailed explanation-1: -Like many facial expressions, the smile can be produced either deliberately by voluntary movement of the Zygomaticus major muscles or spontaneously in response to social or emotional stimuli.

Detailed explanation-2: -Risorius, which is located on each side of your mouth and aids in smiling. Zygomaticus major and minor, which allow you to smile.

Detailed explanation-3: -A Duchenne smile is a natural smile of enjoyment, made by contracting the zygomatic major muscle (the muscle that runs along your cheekbone) and the orbicularis oculi muscle (the muscle that lines the top of your lip). It’s often involuntary and experienced during times of genuine happiness or enjoyment.

Detailed explanation-4: -Pseudobulbar affect (PBA) is a condition that’s characterized by episodes of sudden uncontrollable and inappropriate laughing or crying. Pseudobulbar affect typically occurs in people with certain neurological conditions or injuries, which might affect the way the brain controls emotion.