Reflex Arcs quiz #1 Flashcards
Reflex Arcs quiz #1
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What initiates the stretch reflex, and what is its primary function?
The stretch reflex is initiated by muscle spindles in response to unexpected stretching of a muscle. Its primary function is to cause the muscle to contract, preventing muscle strain and potential injury. Describe the role of reciprocal inhibition during the stretch reflex.
Reciprocal inhibition is a polysynaptic process that occurs during the stretch reflex, causing the antagonistic muscle to relax. This ensures smooth movement by preventing both muscles from contracting simultaneously. What is the tendon reflex, and which sensory receptor initiates it?
The tendon reflex is a polysynaptic reflex initiated by Golgi tendon organs in response to excessive tension in a tendon. It causes the muscle to relax, preventing tendon injury. Explain the concept of reciprocal activation in the tendon reflex.
Reciprocal activation occurs during the tendon reflex, where the antagonistic muscle contracts as the primary muscle relaxes. This helps maintain balance and prevents overextension. How does the flexor (withdrawal) reflex function, and what is its purpose?
The flexor reflex is an ipsilateral, rapid contraction of flexor muscles in response to a painful stimulus, causing withdrawal of the affected body part to protect it from harm. What is the crossed extensor reflex, and when does it occur?
The crossed extensor reflex is a contralateral reflex that occurs simultaneously with the flexor reflex in weight-bearing limbs. It causes extension of the opposite limb to maintain balance during withdrawal. Differentiate between monosynaptic and polysynaptic reflexes with examples from the reflex arcs discussed.
A monosynaptic reflex involves a direct connection between a sensory and a motor neuron, as seen in the stretch reflex. Polysynaptic reflexes involve one or more interneurons, such as reciprocal inhibition, the tendon reflex, reciprocal activation, the flexor reflex, and the crossed extensor reflex. Why is reciprocal inhibition important during the knee jerk (patellar) reflex?
Reciprocal inhibition ensures that the antagonistic muscle (hamstring) relaxes while the quadriceps contract, allowing for a smooth and effective knee extension during the reflex. What would happen if reciprocal inhibition did not occur during a stretch reflex?
If reciprocal inhibition did not occur, both the agonist and antagonist muscles could contract simultaneously, inhibiting the reflex and potentially causing inefficient or restricted movement. How do Golgi tendon organs contribute to muscle safety during intense contractions?
Golgi tendon organs detect excessive tension in tendons and trigger the tendon reflex, causing the muscle to relax and preventing tendon damage or rupture. In the context of stepping on a sharp object, explain the sequence of reflexes that help maintain posture and prevent injury.
When stepping on a sharp object, the flexor reflex causes rapid withdrawal of the affected limb, while the crossed extensor reflex extends the opposite limb to support body weight and maintain balance.
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