Final answer:
The brain stem's respiratory center, specifically within the medulla oblongata, controls the breathing rate by automatically regulating it based on the blood's carbon dioxide levels, oxygen content, and pH levels. Other brain regions like the hypothalamus also influence breathing in response to emotional and environmental factors.
Step-by-step explanation:
The structure that controls our breathing rate, which averages around 14 times per minute, is the brain stem. More specifically, the respiratory center located within the medulla oblongata in the part of the brain stem is responsible for this regulation. This center monitors the level of carbon dioxide and the pH of the blood and sends nerve impulses to the diaphragm via the autonomic nervous system to adjust the rate and depth of breathing accordingly. This adjustment is a response to alterations in blood carbon dioxide, oxygen, and pH levels, aiming to maintain homeostasis.
Unconscious breathing is largely controlled by the medulla and pons, which are part of the brainstem. These respiratory centers automatically regulate the respiratory rate based on the body's needs, which are primarily determined by blood acidity or pH levels. For instance, during exercise, the body produces more carbon dioxide, which leads to an increased respiratory rate to expel the excess carbon dioxide and maintain a stable pH level.
Other regions of the brain, such as the hypothalamus and the limbic system, also influence the regulation of breathing in response to environmental factors like emotions, pain, and temperature changes. For example, stress or a higher body temperature can lead to an increased respiratory rate.