BIO325H5 Lecture Notes - Lecture 2: Exoskeleton, Truss Bridge, Mechanical Advantage
Document Summary
Within the underside of its head this beetle has a differently* shaped tentorial apodeme[red]: two elongated triangular beams, linked by a transverse bridge, align longitudinally atop the gular plate (green). When the adductor mandibular muscles (not shown) contract and squeeze the massive mandibles together on the prey, the tentorium with its bridge opposes stresses arising at the mandible bases. Such a triangle must hold in one fixed shape. If you try the same thing with a four-member assemblage the angles between the parts can continue to change. Trusses are made up of triangles: cantilevers are structures that are not simply supported. Myopophyllumand the pitchers of pitcher plants from a boreal spruce bog. The space between the ribs is criss-crossed by a network or trellis of muscular [and tendon] tissue which runs at roughly 45 to the ribs. The trunk and rib cage of most vertebrates can be modelled as a sort of simply supported beam.
