Identify the INCORRECT statement about the human ear: MCQ with Answer and Explanation

Explanation:
Thyroxine (T4) and Triiodothyronine (T3) are the main hormones secreted by the thyroid gland. They play a crucial role in regulating the basal metabolic rate (BMR), which is the rate at which the body uses energy at rest. They also influence growth, development, and body temperature. Calcitonin, also from the thyroid, regulates blood calcium.

Explanation:
The cardiac conduction system ensures coordinated heartbeats. The sinoatrial (SA) node generates the electrical impulse, acting as the natural pacemaker. The impulse reaches the atrioventricular (AV) node, which delays it slightly to allow the atria to fully contract and empty into the ventricles. The impulse then travels down the Bundle of His to the Purkinje fibers, which rapidly distribute it throughout the ventricular myocardium, causing ventricular contraction. All statements are correct.

Explanation:
The pineal gland, located in the brain, secretes melatonin, which regulates circadian rhythms and the sleep-wake cycle. Its secretion increases in darkness.