The hormone released by the pineal gland of the human brain is concerned with :

Options

A. Anger
B. Body temperature
C. Colouration of skin
D. Sleep

Answer

To solve the question regarding the hormone released by the pineal gland of the human brain, we can follow these steps:

### Step 1: Identify the gland and its location
The pineal gland is an endocrine gland located on the dorsal side of the forebrain.

**Hint:** Remember that the pineal gland is often referred to as the "third eye" due to its location and function.

### Step 2: Determine the hormone secreted by the pineal gland
The main hormone secreted by the pineal gland is melatonin.

**Hint:** Think about the functions of melatonin in relation to sleep and circadian rhythms.

### Step 3: Understand the functions of melatonin
Melatonin is primarily involved in regulating the sleep-wake cycle, also known as the circadian rhythm. It helps signal the body when it is time to sleep and when it is time to wake up.

**Hint:** Consider how changes in light exposure can affect melatonin levels and, consequently, sleep patterns.

### Step 4: Analyze the options given in the question
The options provided in the question include anger, body temperature, coloration of skin, and sleep. Among these, the most relevant function of melatonin is related to sleep.

**Hint:** Focus on the primary role of melatonin in regulating sleep rather than its secondary effects on other functions.

### Step 5: Conclude the answer
Based on the information gathered, the hormone released by the pineal gland is primarily concerned with sleep.

**Final Answer:** The correct answer is option no. 4: sleep.