Knee-jerk reflex All reflex actions occur via a reflex arc. The diagram below illustrates a simple monosynaptic reflex arc. Label the components of the knee-jerk reflex arc in the diagram. Dorsal root ganglion Motor neuron Muscle spindle Patellar tendon Quadriceps muscle Sensory neuron Stimulus Ventral horn
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- The sensory neuron stimulus in the knee-jerk reflex is initiated when the patellar tendon is tapped. This tapping stretches the quadriceps muscle, which contains the muscle spindle. The muscle spindle is sensitive to changes in length of the muscle, so when the Show more…
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Let's construct a diagram of the knee jerk reflex starting with the sensory pathway. Fill in the blanks using the terms in the table below (see Fig. 43.28 and 44.1). Boldfaced terms should go into the (). When a hammer hits the patellar __________, the __________ (__________) stretches slightly, which opens __________- gated __________ in the __________ __________ which is part of the __________ nervous system. __________ rush into the __________ cell, triggering a(n) __________ __________ in the __________. If the hammer tap (__________) is strong enough, the __________ __________ reaches __________ and causes a(n) __________ __________. This __________ __________ is __________ along the __________ towards the __________. Note: Terms can be used more than once. Axon Spinal chord Action potential Propagated Receptor potential Threshold Muscle spindle Sensor Stimulus Tendon Sodium ions Mechanically Sensory neuron Peripheral Ion channel Membrane potential
Adi S.
In the stretch reflex (knee jerk reflex), the muscle stretches and the muscle spindle is excited. The sensory neuron sends an afferent signal to the spinal cord.
Madhur L.
What is the term for a reflex that does not include a CNS component? a. long reflex b. visceral reflex c. somatic reflex d. short reflex
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