Neurons are cells that transmit electrical signals through the nervous system. Motor neurons control muscle activity and movement by carrying impulses from the brain and spinal cord. Sensory neurons ...

Swans do not have teeth. Instead, their strong bills have comb-like, serrated edges called lamellae (singularly, lamella), which act like teeth to grip and tear aquatic plants and small prey. Lamellae ...

Hemifacial spasm is a rare disorder, commonly causing eye and mouth twitching on one side of the face. Common causes include compression of the facial nerve by a blood vessel. Botox injections and ...