When a person cries tear fluid is secreted by a lacrimal gland seen bulging the conjunctiva (muscous membrane covering the eyeball and lining the eyelids). This tear passes through numerous ducts into the conjunctive sac, aided by ocular muscle contraction. From there it reaches the lacrimal sac and through the lacrimal duct it is drained into the nasal cavity. (Lacrimal duct is an anatomical drainage canal which connects the corner of the eye to the lower surface of the nasal cavity.) When there is a sudden discharge of tear, as while crying, the fluid is pooled resulting in congestion.
Another interesting fact is that Nature has provided a flap valve at the terminal part of the canal to prevent tear fluid from being pushed back by air, while sneezing or blowing.
Another interesting fact is that Nature has provided a flap valve at the terminal part of the canal to prevent tear fluid from being pushed back by air, while sneezing or blowing.
