Reflex action is controlled by

Step 1: Analyze the question The question asks which part of the nervous system controls reflex action. Reflexes are rapid, automatic, involuntary responses to a stimulus.

Step 2: Explain the concept

• Spinal reflexes (such as the knee-jerk or withdrawing your hand from a hot object) are coordinated by the spinal cord.
• Cranial (brain) reflexes (such as coughing, sneezing, swallowing, vomiting, and the control of heartbeat and breathing) are coordinated by the medulla oblongata, the lowest part of the brainstem, which joins the spinal cord.

The medulla oblongata is the part of the brain that controls involuntary, automatic actions.

Step 3: Check each option

• A. Cerebellum: controls balance, posture, and coordination of voluntary movement. Not reflexes.
• B. Cerebrum: controls voluntary actions, thinking, memory, and reasoning.
• C. Medulla oblongata: controls involuntary actions such as breathing, heartbeat, and many reflexes. ✔
• D. Olfactory lobe: concerned with the sense of smell.
• E. Pineal body: an endocrine gland that secretes melatonin and regulates sleep rhythms.

Step 4: Answer Among the options given, the medulla oblongata is the correct choice. Note that the spinal cord is the centre for many simple reflexes, but it isn't listed here, so C is the best answer.

Exam tip: Remember the roles with this short list:

• Cerebrum = thinking
• Cerebellum = balance
• Medulla = involuntary actions (reflexes, breathing, heartbeat)

If you see "involuntary" or "automatic" and the spinal cord isn't an option, think medulla oblongata.