page_title: Campaniform sensilla
section_title: Structure
hierarchical_section_title: Campaniform sensilla / Structure
context_page_description: Campaniform sensilla are a class of mechanoreceptors found in insects, which respond to stress and strain within the animal's cuticle. Campaniform sensilla function as proprioceptors that detect mechanical load as resistance to muscle contraction, similar to mammalian Golgi tendon organs. Sensory feedback from campaniform sensilla is integrated in the control of posture and locomotion.
context_section_description: Each campaniform sensillum consists of a flexible dome, which is embedded in a socket within the cuticle and innervated by the dendrites of a single bipolar sensory neuron (see schematic cross-section). Campaniform sensilla are often oval-shaped with long axes of about 5-10 µm (see SEM).
  Campaniform sensilla are distributed across the body surface of many insects. Sensilla with similar orientations are often grouped together in regions where stress is likely to be high, including on the legs, antennae, and wings. For example, stick insects have groups of campaniform sensilla on the trochanter, a group on the proximal femur, a group on the proximal tibia, and a small number of sensilla on the distal end of each tarsomere (see leg schematic). In Diptera like blow flies, the highest density of campaniform sensilla is found at the base of the modified hind-wings, or halteres, which function as gyroscopic sensors of self-motion during flight.
caption: Distribution of groups of campaniform sensilla on a stick insect leg (anterior view). The inset shows a top view of the two groups on the dorsal trochanter (G3 and G4). The sensilla of these groups have mutually perpendicular orientations. Each sensillum is preferentially excited by compression along its short axis (arrows). The proximal group (G3) is oriented perpendicularly to the long axis of the trochanter and excited when the trochanter-femur is bent upward. The more distal group (G4) is oriented in parallel to the long axis of the trochanter and excited when the trochanter-femur is bent downward.