Tears

[1] Tears are made up of water, electrolytes, proteins, lipids, and mucins that form layers on the surface of eyes.

From the punctum, tears will enter the lacrimal sac,[2] then on to the nasolacrimal duct, and finally into the nasal cavity.

[14] Humans and some primates have a much smaller nictitating membrane; this may be because they do not capture prey or root vegetation with their teeth, so that there is no evolutionary advantage of the third eyelid.

In nearly all human cultures, crying is associated with tears trickling down the cheeks and accompanied by characteristic sobbing sounds.

In most Western cultures, it is more socially acceptable for women and children to cry than men, reflecting masculine sex-role stereotypes.

[19][20][21] There is evidence for an interpersonal function of crying as tears express a need for help and foster willingness to help in an observer.

[18] Some modern psychotherapy movements such as Re-evaluation Counseling encourage crying as beneficial to health and mental well-being.

that this would cause salivation while crying due to the inverse improper connection of the lacrimal nucleus to the salivary glands, but this would be less noticeable.

[citation needed] Familial dysautonomia is a genetic condition that can be associated with a lack of overflow tears (Alacrima) during emotional crying.

[citation needed] Pseudobulbar affect (PBA) is a condition involving episodic uncontrollable laughter or crying.

PBA mostly occurs in people with neurological injuries affecting how the brain controls emotions.

[31] Patients with PBA do not experience typical depression symptoms like sleep disturbances or appetite loss.