Black widow spider spinnerets

Spiders have what is called spinneret glands which are usually located on the bottom of the abdomen. These glands produce the silk spiders use when they construct webs. Silk production in the spider occurs within these specialized glands that are capable of the synthesis of large fibrous proteins and the processing of those proteins into a form of insoluble fiber. The major ampullate gland of Latrodectus hesperus (black widow) is similar in morphology to those found in the Araneid spiders. The tail of this gland is highly protein synthetic, giving rise to a core, fibrous protein product. In addition to a storage function, the ampulla region also synthesizes and exports an electron dense material that appears to form a 'coat' surrounding the silk generated within the tail. The duct of the gland consists of at least two distinct cell types: one type contains 'honeycomb' vesicles of unknown function, while the other possesses elaborate apical microvilli that may be involved in the reabsorption of water and subsequent dehydration of the silk. As the silk product transits through these various stages of assembly, it can been seen to undergo a condensation or concentration, possibly reflecting the influence of both the shear forces induced by movement into the duct and the dehydration that is thought to occur there.
spider dissection

spider dissection
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