A reflex that causes reciprocal activation of the antagonist muscle is the a. crossed-extensor, b. flexor, c. tendon, d. muscle stretch.

Verified step by step guidance

1. Identify the type of reflexes mentioned in the options: crossed-extensor, flexor, tendon, and muscle stretch.
2. Understand that reciprocal activation involves the activation of an antagonist muscle when the agonist muscle is contracted.
3. Recall that the tendon reflex, also known as the Golgi tendon reflex, involves the activation of the antagonist muscle to prevent damage from excessive tension.
4. Consider the function of each reflex: the crossed-extensor reflex involves opposite limb extension, the flexor reflex involves withdrawal from a stimulus, the tendon reflex involves tension regulation, and the muscle stretch reflex involves muscle length regulation.
5. Conclude that the tendon reflex is the one that causes reciprocal activation of the antagonist muscle.

Key Concepts

Reciprocal Inhibition

Reciprocal inhibition is a physiological process where the activation of one muscle (the agonist) leads to the simultaneous relaxation of its antagonist muscle. This mechanism is crucial for coordinated movement, allowing for smooth transitions between muscle contractions and relaxations. For example, when the biceps contract to flex the elbow, the triceps must relax to allow this movement.

Reflex Arcs

Reflex arcs are neural pathways that mediate reflex actions, involving sensory neurons, interneurons, and motor neurons. They enable quick responses to stimuli without the need for conscious thought, ensuring rapid reactions to potentially harmful situations. In the context of the question, reflex arcs are responsible for the reciprocal activation of muscles during reflex actions.

Types of Reflexes

There are several types of reflexes, including flexor, crossed-extensor, tendon, and muscle stretch reflexes. Each type serves a specific function; for instance, the flexor reflex helps withdraw a limb from a painful stimulus, while the crossed-extensor reflex stabilizes the body by activating opposite limb muscles. Understanding these reflex types is essential for identifying the correct answer to the question.