Lacrimal gland

The lacrimal glands are paired exocrine glands, one for each eye, found in most terrestrial vertebrates and some marine mammals, that secrete the aqueous layer of the tear film.

In humans, they are situated in the upper lateral region of each orbit, in the lacrimal fossa of the orbit formed by the frontal bone.

Inflammation of the lacrimal glands is called dacryoadenitis.

The lacrimal gland produces tears which are secreted by the lacrimal ducts, and flow over the ocular surface, and then into canals that connect to the lacrimal sac.

From that sac, the tears drain through the lacrimal duct into the nose.

Anatomists divide the gland into two sections, a palpebral lobe, or portion, and an orbital lobe or portion.

The smaller palpebral lobe lies close to the eye, along the inner surface of the eyelid; if the upper eyelid is everted, the palpebral portion can be seen.

The orbital lobe of the gland, contains fine interlobular ducts that connect the orbital lobe and the palpebral lobe.

They unite to form three to five main secretory ducts, joining five to seven ducts in the palpebral portion before the secreted fluid may enter on the surface of the eye.

Tears secreted collect in the fornix conjunctiva of the upper lid, and pass over the eye surface to the lacrimal puncta, small holes found at the inner corner of the eyelids.

These pass the tears through the lacrimal canaliculi on to the lacrimal sac, in turn to the nasolacrimal duct, which dumps them out into the nose.Lacrimal glands are also present in other mammals, such as horses.