What if the lacrimal gland is too developed? Sometimes I laugh and cry.

Anthropologists have found that among many primates, human beings are the only members who can cry and shed tears. Tears are a simple behavior that people are born with. No one can learn. It is as instinctive as heart beating and kidney excretion, as spontaneous as sighing and sneezing. So, why do people cry? What effect does tears have on human body? What's the point? This seemingly simple question has long puzzled researchers. Charles Darwin, the founder of the theory of evolution, believes that tears are a "relic" of some kind of evolution, which has nothing to do with the competition for survival in the process of evolution. Darwin's analysis: When crying, the microvessels around the eyes will be congested, while the small muscles will contract to protect the eyes, thus making the lacrimal gland secrete tears. Darwin believed that tears themselves are meaningless "by-products" for the human body. Besides crying, there are roughly three reasons for crying. First of all, excessive tear secretion is often related to the stimulation of cornea, iris, ciliary body and other tissues by the lesion; Tears caused by smoke and chemical stimulation also belong to this category. The second is that the normal secretion of tears can not be discharged into the nasal cavity smoothly due to the obstruction of lacrimal duct system, resulting in reflux overflow, which can be confirmed by lacrimal duct irrigation in clinic. Thirdly, because the lower eyelid is everted, the lacrimal punctum can't cling to the lacrimal caruncle, so that the capillary shunt of tears is destroyed, and tears can't enter the nasal cavity from the lacrimal canaliculus, thus overflowing. This kind of tears mainly occurs in the elderly with decreased tension of orbicularis oculi muscle and facial paralysis patients with closed eyelids.