CVS Practice Test

What mechanism induces the oculocardiac reflex?

1. Pressure on the globe of the eye

2. Traction on extraocular muscles

3. Both pressure on the eye and traction on extraocular muscles

4. Rapid eye movement

The correct answer is: Both pressure on the eye and traction on extraocular muscles

The oculocardiac reflex is a physiological response that occurs when specific stimuli affect the eye region, leading to a decrease in heart rate (bradycardia). The correct mechanism that induces this reflex involves stimulation of the eye through both pressure on the globe of the eye and traction on the extraocular muscles. When pressure is applied to the eyeball, it activates the afferent pathway via the ciliary ganglion, which is associated with the trigeminal nerve. This stimulation sends signals to the central nervous system that, in turn, trigger a response through the efferent vagus nerve, resulting in a decrease in heart rate. Additionally, traction on the extraocular muscles can cause a similar response by impacting the nerves involved in the oculocardiac reflex. Therefore, both stimuli—pressure and traction—contribute to activating this reflex, making the combined option the most accurate representation of the mechanisms involved. This understanding highlights the complex interplay between ocular and cardiac systems in neurophysiology.