Stress

Notes

Stress, regardless of age, provokes a series of changes within the brain and the body, mainly revolving around the HPA (Hypothalamic-Pituitary-Adrenal) axis. The HPA access includes the following structures

1. Hypothalamus: The hypothalamus is a region of the brain responsible for the production of several releasing and inhibiting hormones, which control the release of hormones from the pituitary gland. One of these is corticotropin-releasing hormone (CRH), which initiates the stress response.
2. Pituitary gland: In response to CRH from the hypothalamus, the pituitary gland releases adrenocorticotropic hormone (ACTH). The pituitary is a pea-sized gland located at the base of the brain, and it plays a major role in regulating vital body functions and general wellbeing.
3. Adrenal glands: Upon receiving ACTH, the adrenal glands, located atop the kidneys, release cortisol, the body's main stress hormone. Cortisol prepares the body to respond to stressful situations by altering immune system responses and suppressing the digestive system, the reproductive system, and growth processes. This complex natural alarm system also communicates with regions of the brain that control mood, motivation, and fear.

The HPA access regulates many of the body's processes, including reactions to stress, mood and emotions, energy storage, and immune responses. Although stress can sometimes be beneficial, for instance, as a motivator to overcome challenges, chronic or ongoing stress can have detrimental effects. These effects vary based on the severity of stress (low, moderate, high) and the developmental stage (childhood, adolescence, adulthood).

Hindbrain

1. Medulla Oblongata: The medulla oblongata sits at the base of the brain, directly connected to the spinal cord. It is responsible for managing several physiological functions including heart rate (how quickly or slowly the heart beats), blood pressure, and respiration. When a person is startled or scared, it's the medulla oblongata that triggers the heart to beat faster. The medulla also oversees functions such as swallowing (for example, when a person swallows food), vomiting (like when someone is ill), and sneezing (as a response to an irritant in the nose).
2. Pons: Located above the medulla oblongata and below the midbrain, the pons acts as a message station between various areas of the brain, particularly between the cerebral cortex and the cerebellum. It also helps control functions like sleep (for instance, it aids in transitioning between sleep and wakefulness), respiration (it helps regulate the pace of breathing), and bladder control. It is also involved in auditory processes (like hearing a song), maintaining equilibrium (like keeping balance while walking on a narrow path), taste, eye movement, facial expressions, and posture.
3. Cerebellum: Positioned behind the brainstem, the cerebellum plays a key role in functions related to movement and motor skills. These include coordination, precision (like when painting a delicate picture), and timing (as required when playing a musical instrument). The cerebellum is also crucial in motor learning (like learning to ride a bike). More recent research suggests that the cerebellum may also be involved in certain cognitive processes, such as focusing attention, language abilities (like when learning a new language), understanding music, and processing other sensory temporal information.