What is the name of the glandlike structure in the brain that regulates sleep patterns?

The pineal gland is the glandlike structure in the brain that plays a crucial role in regulating sleep patterns. It produces the hormone melatonin, which helps to regulate circadian rhythms and the sleep-wake cycle. The secretion of melatonin increases in response to darkness and decreases with light exposure, signaling the body when it is time to sleep. This function is vital for maintaining a regular sleep pattern and overall health.

Other glands mentioned, such as the pituitary and hypothalamus, have important roles in the endocrine system and regulation of various bodily functions, but they do not specifically regulate sleep patterns like the pineal gland does. The thyroid gland primarily regulates metabolism and does not have a direct role in sleep regulation.