This section details how the spider silk MA gland regulates material synthesis and assembly at the tissue, cellular, and molecular scales. At the tissular scale, the MA gland, located in the spider's abdomen, is organized in three regions: the tail for spidroin secretion, the ampulla for storage and coatings, and the duct for solid material formation 186 (Fig. ). The tail is a long, widening tubular epithelium on the anterior side of the organ (zone A). It synthesizes spidroin in secretory vesicles for its release in the lumen 187 . The ampulla stores the liquid silk dope at high concentrations , enabling rapid, on demand, spinning . The ampulla is itself segmented in two regions, zone B and C, secreting each different coatings layers 187 . These middle and outer layers wrap the core silk dope produced in the tail, creating a concentric meso-structure. The third part of the organ, the duct, can be seen as an extruder and is specialized in converting the silk dope from liquid phase to solid fibers. To do so, it regulates the ChemµEnv in the lumen, which guides spidroins' proper protein folding . Pulling the hanging thread at the posterior side, exiting the spigot, initiates the process. Pulling the fiber manually, namely forced silking, also induces spinning. Tensile forces propagate via intermolecular interactions, from the spigot to the ampulla, initiating the flow . A ratchet and pump mechanism is hypothesized to restart spinning if the fiber breaks within the gland . The solidification of silk solution into fiber occurs as it flows from the ampulla and through the duct. The tapering funnel and duct induce shear forces 190 and align the molecules 191 , improving the resulting material properties . The funnel's thicker cuticle connects the flexible duct to the ampulla 194 , and is hypothesized to prevent the dope from excessive shearing when the spider moves around . The thick cuticle also helps to oppose the induced forces from the flow and may mechanically protect the underlying tissue during spinning. The duct regulates ChemµEnvs, establishing gradients of salts, pH and water content along its length 195 . As it flows through these conditions, the dope self-assembles in a hierarchical material . To complete the conversion to solid fiber and reduce water losses, terminal tubules on the posterior side pump remaining water 196 and the spigot's lips retain the aqueous phase inside . This example shows how a multi-sectional organ can perform coordinated functions for material production.