Mueller's muscle is under what type of control?

Mueller's muscle, also known as the superior tarsal muscle, is primarily under sympathetic control. This muscle plays a role in elevating the upper eyelid and maintaining eyelid position. The sympathetic nervous system is responsible for the innervation of Mueller's muscle, allowing for the elevation of the eyelid in response to stimuli such as stress or excitement.

Understanding the role of sympathetic activation in eyelid maintenance is crucial, especially in the context of conditions such as Horner's syndrome, where sympathetic innervation is disrupted, leading to ptosis (drooping of the eyelid) due to Müller’s muscle dysfunction. This illustrates the direct relationship between sympathetic nerve activity and the functional state of Mueller's muscle. Other forms of control, such as voluntary or parasympathetic, do not apply here, as Mueller's muscle does not respond to voluntary control in the same way skeletal muscles do, nor is it influenced by parasympathetic signals.