VERY IMPORTANT TO STUDY

Explain how the body physically responds when experiencing strong emotions (e.g., fear or happiness)

When a person experiences strong emotions, such as fear or happiness, the body shows clear physical responses. For example, during fear, heart rate increases, breathing becomes faster, and muscles tense. In happiness, people may smile, feel relaxed, and experience a release of “feel-good” chemicals like dopamine. These changes are controlled by the autonomic nervous system (ANS), which automatically regulates bodily functions. 

The autonomic nervous system (ANS) has two branches. Describe the role of the sympathetic and parasympathetic nervous systems in emotional arousal. 

The ANS has two main branches: the sympathetic nervous system and the parasympathetic nervous system. The sympathetic system is responsible for the fight-or-flight response, preparing the body for action by increasing heart rate, dilating pupils, and releasing adrenaline. In contrast, the parasympathetic system calms the body after the arousal has passed, returning it to a state of rest by slowing the heart rate and promoting digestion. Together, these systems balance emotional arousal and recovery. 

Identify and explain the function of the amygdala in processing emotions. Give an example of how it might respond to a threatening stimulus. 

The amygdala is a small structure in the limbic system that is crucial for detecting and processing emotions, especially fear and threats. For example, if someone suddenly sees a snake, the amygdala quickly recognises the danger and triggers the fight-or-flight response through activation of the sympathetic nervous system. This helps the body prepare for survival before the person even consciously thinks about the threat. 

Describe the role of the hippocampus in emotion and memory. Provide an example of how it helps link past experiences to current emotions. 

The hippocampus also plays a key role in emotion, but its main function is linking memory and emotion. It helps store emotional experiences and connects current events to past ones. For example, if someone had a frightening experience with a dog as a child, the hippocampus may retrieve that memory when they see a dog again, influencing their emotional response of fear. 

Compare the functions of the amygdala and hippocampus in relation to emotional responses. 

Although both the amygdala and hippocampus are involved in emotional responses, they serve different functions. The amygdala specialises in detecting immediate threats and triggering fast, instinctive reactions, while the hippocampus provides context by linking emotions to past experiences and memories. Together, they ensure emotional responses are both quick and informed by past learning. 

Explain how the hypothalamus regulates sleep, including its role in controlling the release of melatonin. 

The hypothalamus plays a central role in regulating sleep by controlling the body’s circadian rhythms. Within the hypothalamus, the suprachiasmatic nucleus (SCN) acts as the body’s “master clock.” It receives information about light from the retina and uses this to signal the pineal gland when to increase or decrease melatonin production. By doing this, the hypothalamus helps the body distinguish between day and night and regulate the timing of sleep. 

Describe the function of the pineal gland in producing melatonin and explain how this hormone influences sleep. 

The pineal gland is responsible for producing the hormone melatonin. When the SCN detects low levels of light (such as at night), it stimulates the pineal gland to release melatonin into the bloodstream. Melatonin makes a person feel sleepy and prepares the body for rest. In contrast, when it is light, the SCN reduces melatonin production, which promotes wakefulness. 

Outline the process by which light exposure affects melatonin production and sleep regulation. 

Light exposure strongly influences melatonin production. When light enters the eyes, photoreceptors in the retina send signals to the SCN, which suppresses melatonin release from the pineal gland. This explains why people are usually more alert during the day and sleepier at night. Artificial light at night, such as from screens, can disrupt this process by reducing melatonin production and delaying sleep onset. 

Evaluate the importance of melatonin in maintaining circadian rhythms, using examples. 

Melatonin is important in maintaining circadian rhythms, which are the roughly 24-hour cycles of biological processes. For example, melatonin secretion usually peaks at night and is lowest during the day, keeping the sleep-wake cycle in rhythm with the external environment. Without adequate melatonin release at the right times, the circadian rhythm can become misaligned, leading to poor sleep quality and daytime fatigue. 

Discuss how a disruption to melatonin production might affect a person’s sleep-wake cycle (e.g., shift work or jet lag). 

A disruption to melatonin production can significantly affect a person’s sleep-wake cycle. For instance, in shift work, exposure to light at night suppresses melatonin production, making it difficult for workers to sleep during the day. Similarly, in jet lag, melatonin levels may not match the new time zone, causing sleep disturbances and fatigue until the body adjusts. In both cases, the normal circadian rhythm is thrown out of balance, highlighting the crucial role of melatonin in sleep regulation.