Back to: ZOOLOGY 400 Level
Welcome to class!
Hey there, brilliant learner! It’s time to put on our thinking caps and dive into an exciting new topic—the control of breathing. Breathing might seem like something we do without thinking, but there’s actually a fascinating system in our body that controls how and when we breathe. Let’s explore how this works and why it’s so important for your body’s function!
Control Of Breathing
What is Breathing Control?
Breathing is controlled by a part of your brain called the medulla oblongata, which is located in the brainstem. This part of the brain constantly monitors the levels of oxygen and carbon dioxide in your blood, and it adjusts your breathing rate accordingly to make sure your body gets the right balance of gases. If there’s too much carbon dioxide in the blood, for example, your breathing rate will increase to get rid of it quickly. Similarly, if oxygen levels are low, the brain sends signals to increase the rate and depth of breathing.
The Role of the Medulla Oblongata
The medulla oblongata is your body’s “breathing controller.” It constantly checks the level of carbon dioxide (CO₂) in your blood, because the body is more sensitive to CO₂ levels than to oxygen levels. When CO₂ builds up, it makes the blood more acidic, and this triggers the breathing centres in the medulla to increase the breathing rate, so that more oxygen is brought in and more carbon dioxide is expelled.
Example: After a long run, you might notice that your breathing becomes faster. That’s because your body is trying to get rid of the extra carbon dioxide that’s built up in your muscles and blood during the intense activity.
Chemoreceptors and Their Role
Your body has special sensors called chemoreceptors that monitor the levels of oxygen and carbon dioxide in your blood. These sensors are located in two places:
In the carotid arteries (located in the neck)
In the aorta (the large artery that carries blood from the heart)
These chemoreceptors send signals to the brain to adjust the breathing rate when needed. If oxygen levels drop too low or carbon dioxide levels rise too high, the chemoreceptors send a signal to the breathing centres in the brainstem, which then send messages to the respiratory muscles to adjust the rate and depth of breathing.
Example: If you’re in a high-altitude area where there’s less oxygen, the chemoreceptors in your carotid arteries will detect the lower oxygen levels and trigger faster, deeper breathing to bring in more oxygen.
The Role of the Medullary Respiratory Centres
The medullary respiratory centres in the brainstem are made up of two parts:
The Dorsal Respiratory Group (DRG): This area is responsible for sending signals to the muscles involved in normal, rhythmic breathing.
The Ventral Respiratory Group (VRG): This area helps control forceful breathing, such as when you’re exercising or need to take a deep breath.
Together, these centres coordinate the muscles that make breathing possible, ensuring that you take in the oxygen you need and expel carbon dioxide efficiently.
Example: During sleep, the DRG controls the basic, relaxed rhythm of your breathing. When you’re playing sports, the VRG helps you breathe more deeply and quickly to match the increased demand for oxygen.
Voluntary Control of Breathing
While breathing is mostly controlled automatically by the brainstem, you also have some voluntary control over your breathing. For example, you can hold your breath, take a deep breath, or even control your breathing rate to calm down. This voluntary control happens because the brain can override the automatic signals temporarily.
Example: When you’re swimming, you might hold your breath underwater. That’s a conscious decision, but when you surface, your brain takes over and restores your normal breathing rhythm.
Other Factors Influencing Breathing
While the brainstem controls breathing based on gas levels in the blood, other factors can influence how we breathe:
Emotions: Strong emotions like fear, excitement, or stress can make your breathing faster or more shallow. For instance, you might start breathing more quickly when you’re nervous or anxious.
Exercise: Physical activity increases the demand for oxygen in your muscles, which causes your breathing rate to increase.
Temperature: Hot or cold temperatures can also affect how quickly or slowly you breathe.
Example: When you’re running or playing football, your muscles use more oxygen and produce more carbon dioxide, so your body increases your breathing rate to meet the demand.
Summary
- The medulla oblongata in the brain controls your breathing rate by monitoring the levels of carbon dioxide in the blood.
- Chemoreceptors in the carotid arteries and aorta detect changes in oxygen and carbon dioxide levels and send signals to the brain to adjust breathing.
- The Dorsal Respiratory Group (DRG) controls normal, rhythmic breathing, while the Ventral Respiratory Group (VRG) controls forceful breathing.
- Voluntary control allows you to consciously alter your breathing, like holding your breath or taking a deep breath.
- Breathing can also be influenced by emotions, exercise, and temperature.
Evaluation
- How does the medulla oblongata regulate breathing?
- What is the role of chemoreceptors in the control of breathing?
- How does the DRG differ from the VRG in the brainstem?
- What is the effect of exercise on breathing rate?
- How can emotions influence the way we breathe?
Great work, you’ve just learned about the incredible control system that regulates how you breathe! This system makes sure your body gets the oxygen it needs and gets rid of carbon dioxide in the most efficient way. Keep up the fantastic effort—you’re doing amazing! Keep exploring, keep asking questions, and know that with each lesson, you’re getting closer to mastering your knowledge. I’m so proud of you!