Fig 1.
The knee-jerk- and withdrawal reflexes.
(a) The knee-jerk reflex illustrated in a secondary school textbook (reproduced and translated with permission from [35]). (b) The withdrawal reflex as illustrated in a national digital resource for teaching material (reproduced under the Creative Common license). (c) The knee-jerk reflex with a neural network similar to figure 10–1 A in [37]. The reflex is elicited by tapping the tendon of the Quadriceps (extensor) muscle with a reflex hammer just below the knee cap. This pulls on the tendon and stretches the extensor muscle as well as the muscle spindle which is a sensory organ within the quadriceps muscle. This activates the sensory neuron which sends nerve signals into spinal cord. In the spinal cord the sensory neuron splits into two terminal branches. One branch conveys the nerve signal through an excitatory synapse to the extensor motor neuron which passes the signal on to the extensor muscle making it contract. The other branch conveys the nerve signal to the inhibitory interneuron which passes the signal on through an inhibitory synapse to the flexor motor neuron which becomes inhibited. This makes the flexor muscle relax while the extensor muscle contracts, and the result is an extension of the lower leg. In the illustration, each extensor and flexor motor neuron represent a population of many cells.
Table 1.
Demographic information about the experts attending the study.
Table 2.
Initial list of statements considered important knowledge about the nervous system (premade statements).
Table 3.
Transformation of a statement through the first round with the Delphi-technique.
Table 4.
Ranking of revision categories by priority.
Table 5.
The categorization of statements into overriding themes.
Fig 2.
The quantitative progression towards consensus during the Delphi-process.
Average percentage of experts agreeing, disagreeing and being neutral to the statements during four rounds with the Delphi-method. In the first round, the experts responded freely, and the agreements were interpreted from their answers. In the second, third and fourth round, the experts responded to a three-point Likert-scale with the alternatives agree, disagree and neutral.
Table 6.
Transformation of a statement throughout the Delphi process.
Table 7.
Ranking of revision categories by priority throughout the Delphi process.
Table 8.
Knowledge themes and principles considered important for understanding the nervous system in the context of secondary biology and science education.