Histology of lacrimal gland with difference between parotid and lacrimal gland

Lacrimal gland

It is situated external to the eye located in the superolateral aspect of the orbit .

It is an exocrine gland compound tubuloalveolar glands. It is divided into many lobule by connective tissue . each lobule contain many acini .  Each acinus contain large lumen and  a grape-like mass of lacrimal gland cells with their apices pointed to a central lumen. Each acinus is composed of column-shaped cells of the serous type, resembling the parotid acinar cells. These cells show lightly stained secretory granules, and a basal lamina separates them from the surrounding connective tissue. well-developed myoepithelial cells surround the secretory portions of the lacrimal gland.

Ducts: approximately 12 ducts drain from the lacrimal gland in the reflection of conjunctiva . It contains intralobular and interlobular duct but no striated duct.  Parotid gland has striated duct.

Drainage of tear:

Conjunctival sac

Lacrimal puncta

Lacrimal canaliculus

Lacrimal sac

Nasolacrimal duct

Inferior meatus of the nasal cavity

Secretion : it producing a lysozyme rich serous fluid with an alkaline pH. It contain an enzyme that hydrolyzes the cell walls of certain species of bacteria, facilitating their destruction.

It protect corneal epithelium and contain antibacterial and UV protective agents .

 Blood supply

The lacrimal artery derived from the ophthalmic artery supplies the lacrimal gland. Venous blood returns via the superior ophthalmic vein.

Lymphatic drainage

The glands drain into the superficial parotid lymph nodes

Nerve supply

The lacrimal nerve, derived from the ophthalmic nerve, supplies the sensory component of the lacrimal gland.

The greater petrosal nerve, derived from the facial nerve, supplies the parasympathetic autonomic component of the lacrimal gland.

The sympathetic postganglionic fibers originate from the superior cervical ganglion.

Clinical anatomy : Inflammation of the lacrimal glands is called dacryoadenitis

Retromammary space

•      Retromammary space is a loose areolar tissue  that separates the breast from the

     pectoralis major muscle.

•      The retromammary space is often the site of breast implantation due to its location away from key nerves and structures that support the breast.

•      Clinical importance: Cancer cells spread through retromammary space.