Regulation Of Respiration: Definition, Function And Diagram

Edited By Irshad Anwar | Updated on Jul 02, 2025 06:41 PM IST

What Is Respiration?

Respiration is an essential physiological activity that preserves the optimum level of oxygen and carbon dioxide within the body. This article elaborates on mechanisms and factors for the control of respiration, so it's a very essential material for examinations like NEET preparation.

Neural Control Of Respiration

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Respiration is controlled by respiratory centres located in the brain stem.

Respiratory Centers In The Brain

The medullary respiratory centre includes the dorsal and ventral respiratory groups. Thus, the DRG establishes the fundamental rhythm of breathing, while the VRG does Voluntary breathing.

What Is The Role Of The Medullary Respiratory Center?

The medullary respiratory centre coordinates patterns of breathing in response to information received through sensory input.

Role Of The Pontine Respiratory Group

The pontine respiratory group sharpens the breath rhythm into transitions between inspiration and expiration and vice versa.

Chemical Regulation Of Respiration

The chemoreceptors monitor oscillations in the blood's CO2, O2, and pH levels. Sensory input regarding these variables is subsequently sent to the CPG with commands to either raise or lower the breathing cycle to re-balance the concentration of chemicals back to homeostatic levels within the body.

Chemoreceptor Function

The central chemoreceptors are in the medulla sensitive to changes in CO2. In contrast, peripheral chemoreceptors that lie in the carotid bodies and aortic bodies are sensitive to O2 and pH

The Effects Of Co2, O2, And Ph Level On Respiration

High concentration of CO2 rate of breathing increases;

When the rate of breathing becomes too low with the low concentration of oxygen, then peripheral chemoreceptors start shifting breathing

Respiratory Regulation Mechanisms

The body uses multiple feedback systems to govern breathing efficiently.

Feedback Systems In Respiratory Control

These involve sensors that sense changes, control centres that change the rate and depth of respiration, and the effectors that carry out the ultimate response—respiratory homeostasis.

Hering-Breuer Reflex

This reflex prevents overinflation of the lungs by inhibiting the inspiratory neurons through the activation of stretch receptors in the lungs.

Role Of Proprioceptors When The Body Is Exercising

Proprioceptors in muscles and joints stimulate the respiratory centres to increase the rate of breathing during exercise.

Factors Affecting Respiration

There are some factors which influence the rate of respiration and the depth of respiration.

Physical Factors

The respiration rate will increase to provide a greater amount of oxygen to the muscle due to exertion.

Emotional Factors

Stress and anxiety may affect breathing patterns, in which, usually the rate of respiration will be increased.

Chemical Factors

The blood levels of CO2, O2 and pH directly vary and impact respiration

Diseases Of Respiratory Control

Familiarity with the most common diseases will help you recognize and manage disorders of respiratory control

Most Common Diseases

Sleep apnea and respiratory depression represent two diseases that involve alterations of normal respiratory control

Agent And Effect Of Dis-Ordered Respiration

This can be caused by damage to nerves, imbalance in chemicals, or sometimes even by not providing the correct amount of oxygen to tissues.

Recent Research Progress In Respiratory Control

The continuous research in respiratory control has come up with many breakthroughs. These include the following:

New Insights Into The Control Of Breathing

Not long ago, the discovery of many new molecular pathways and mechanisms of participation in breathing control was made.

The Technological Advancement In The Monitoring Of Respiratory Functions

New inventions in medical technology have widened the scope of managing and monitoring existing respiratory disorders.

Recommended video on Regulation Of Respiration

Frequently Asked Questions (FAQs)

1. What are the major centres involved in the regulation of respiration?

Mainly, it is the medullary respiratory centre and the pontine respiratory group: DRG and VRG.

2. What is the effect of chemoreceptors on respiration?

Chemoreceptors continuously monitor the CO2 and O2 levels and pH and make requisite changes in the respiratory rate to maintain homeostasis.

3. Name the function of the medullary respiratory centre.

The medullary respiratory centre integrates sensory input to modulate respiratory patterns to maintain a stable breathing rhythm.

4. How does physical activity affect respiratory rate?

The rate of respiration would be raised to meet the enhanced oxygen demands of the muscles in the event of muscular exercise.

5. Some common disorders related to the regulation of respiration?

Examples include sleep apnea, respiratory depression, and disorders such as those resulting in nerve damage or chemical imbalance that damages respiratory control.

6. What is the role of nitric oxide in respiratory regulation?

Nitric oxide (NO) plays several roles in respiratory regulation. It acts as a bronchodilator, helping to keep airways open. NO also helps regulate pulmonary blood flow, matching it to ventilated areas of the lung. Additionally, NO produced in the nasal passages may enhance oxygen uptake in the lungs by a small amount.

7. How does the respiratory system respond to changes in blood pH not caused by CO2?

When blood pH changes due to non-respiratory causes (e.g., metabolic acidosis or alkalosis), the respiratory system responds to help compensate. For metabolic acidosis, breathing rate and depth increase to expel more CO2, making the blood less acidic. For metabolic alkalosis, breathing slows down to retain more CO2, making the blood more acidic.

8. What is the role of carbon monoxide in respiratory regulation?

While carbon monoxide (CO) is typically thought of as a poison, small amounts are produced naturally in the body and may play a role in respiratory regulation. CO can influence the activity of respiratory neurons and may modulate the sensitivity of peripheral chemoreceptors. However, its exact physiological role in breathing control is still being researched.

9. How does respiratory regulation change during pregnancy?

During pregnancy, several factors affect respiratory regulation. Increased progesterone levels enhance sensitivity to CO2, leading to an increase in breathing rate and depth. The growing uterus also puts pressure on the diaphragm, altering lung volumes. These changes result in a sensation of breathlessness for many pregnant women, even at rest.

10. How does the respiratory system respond to increased atmospheric pressure, such as in deep-sea diving?

Under increased atmospheric pressure, the partial pressures of gases in the lungs increase. This can lead to higher levels of dissolved gases in the blood, including nitrogen and oxygen. The respiratory system must adapt to prevent oxygen toxicity and to manage the risk of decompression sickness when returning to normal pressure. Breathing rate may decrease due to the denser air and increased work of breathing.

11. What is central sleep apnea and how does it relate to respiratory regulation?

Central sleep apnea is a disorder where the brain temporarily fails to send signals to the breathing muscles, causing pauses in breathing during sleep. It's directly related to respiratory regulation as it involves a malfunction in the central control of breathing, often due to issues with the brainstem's sensitivity to CO2 or problems with the respiratory rhythm generators.

12. How does chronic obstructive pulmonary disease (COPD) affect respiratory regulation?

In COPD, airflow limitation leads to CO2 retention. Over time, the body adapts by becoming less sensitive to high CO2 levels, relying more on low oxygen levels to drive breathing. This shift in respiratory regulation can lead to chronic hypercapnia (high blood CO2) and can complicate the management of acute exacerbations.

13. What is hyperventilation and how does it affect the body?

Hyperventilation is excessive breathing that leads to a decrease in blood CO2 levels. This causes blood pH to become more alkaline, which can lead to symptoms such as dizziness, tingling in the extremities, and even fainting. The body tries to correct this by reducing the drive to breathe, which can paradoxically make a person feel short of breath.

14. What is the concept of respiratory plasticity?

Respiratory plasticity refers to the ability of the respiratory control system to undergo persistent changes in structure or function in response to experiences or environmental changes. This can include adaptations to chronic conditions like living at high altitude, or recovery of function after injury to respiratory control centers.

15. What is the relationship between respiratory regulation and blood pressure control?

Respiratory regulation and blood pressure control are closely interlinked. Changes in breathing can affect blood pressure through alterations in intrathoracic pressure, which influences venous return to the heart. Conversely, baroreceptor reflexes that regulate blood pressure can also influence breathing patterns. This interaction is part of the complex integration of cardiovascular and respiratory systems.

16. How does exercise affect the regulation of respiration?

During exercise, increased muscle activity produces more CO2 and lowers blood pH. This stimulates chemoreceptors, which signal the respiratory centers to increase breathing rate and depth. Additionally, the motor cortex sends signals to the respiratory centers in anticipation of increased oxygen demand, further boosting ventilation.

17. How does altitude affect respiratory regulation?

At high altitudes, the partial pressure of oxygen in the air decreases, leading to less oxygen in the blood. This stimulates peripheral chemoreceptors, causing an increase in breathing rate and depth. Over time, the body acclimatizes by increasing red blood cell production and enhancing the sensitivity of chemoreceptors to low oxygen levels.

18. How do pain and discomfort affect respiratory regulation?

Pain and discomfort can significantly alter breathing patterns. Acute pain often leads to rapid, shallow breathing as part of the body's stress response. Chronic pain, especially in the chest or abdomen, can cause people to unconsciously limit their breathing depth to avoid discomfort, potentially leading to inadequate ventilation.

19. How do emotions affect breathing?

Emotions can significantly influence breathing patterns through connections between the limbic system (which processes emotions) and the respiratory centers. For example, anxiety or fear can lead to rapid, shallow breathing, while relaxation can result in slower, deeper breaths. This emotional-respiratory link is the basis for many relaxation techniques.

20. How does sleep affect respiratory regulation?

During sleep, especially in deep stages, the body's sensitivity to CO2 decreases, and breathing becomes slower and more regular. Rapid Eye Movement (REM) sleep can cause temporary paralysis of respiratory muscles, leading to slight irregularities in breathing. These changes can exacerbate breathing disorders like sleep apnea.

21. How does the brain control breathing?

The brain controls breathing through specialized regions in the brainstem called respiratory centers. These include the medulla oblongata, which sets the basic rhythm of breathing, and the pons, which fine-tunes the pattern. These centers receive input from various sensors and adjust breathing rate and depth accordingly.

22. What is the difference between voluntary and involuntary control of breathing?

Breathing is unique in that it can be both voluntary and involuntary. Involuntary breathing is controlled by the respiratory centers in the brainstem and occurs automatically. Voluntary control, such as holding your breath or intentionally changing your breathing pattern, involves the motor cortex overriding the automatic control temporarily.

23. What is the role of proprioceptors in respiratory regulation?

Proprioceptors in the respiratory muscles and joints of the rib cage provide information about the position and movement of the chest wall. This feedback helps coordinate respiratory muscle activity and contributes to the overall control of breathing patterns, especially during changes in body position or physical activity.

24. What is the role of mechanoreceptors in the respiratory system?

Mechanoreceptors in the airways, lungs, and respiratory muscles provide feedback about lung inflation, airway irritation, and muscle stretch. This information helps fine-tune breathing patterns, triggers protective reflexes like coughing, and contributes to the overall coordination of the respiratory cycle.

25. What is the role of astrocytes in central chemoreception and respiratory regulation?

Recent research has highlighted the important role of astrocytes, a type of glial cell in the brain, in central chemoreception. Astrocytes can detect changes in CO2/pH and communicate this information to neurons in the respiratory centers. This discovery has expanded our understanding of how the brain senses and responds to changes in blood chemistry to regulate breathing.

26. How does the concept of respiratory drive relate to mechanical ventilation?

Respiratory drive refers to the body's urge to breathe. In mechanical ventilation, care must be taken not to over-ventilate patients, as this can suppress their natural respiratory drive. Conversely, under-ventilation can lead to increased respiratory drive and patient discomfort. Understanding and managing respiratory drive is crucial for successful weaning from mechanical ventilation.

27. What is periodic breathing and how does it relate to respiratory regulation?

Periodic breathing is a cyclical pattern of alternating periods of deep and shallow breathing or even brief pauses in breathing. It can occur in healthy individuals at high altitudes or during sleep, but it's also associated with certain medical conditions. It represents a dysregulation of the normal respiratory control mechanisms, often due to increased sensitivity to CO2 changes.

28. How do respiratory regulations differ in newborns compared to adults?

Newborns have immature respiratory control systems. They rely more heavily on peripheral chemoreceptors and have a higher sensitivity to low oxygen levels compared to adults. Their breathing patterns are also more irregular, and they are more prone to periodic breathing. As they develop, their respiratory regulation becomes more similar to that of adults.

29. What is the role of baroreceptors in respiratory regulation?

While baroreceptors primarily regulate blood pressure, they indirectly influence respiration. Changes in blood pressure detected by baroreceptors can lead to adjustments in breathing to help maintain cardiovascular homeostasis. For example, a sudden drop in blood pressure might trigger deeper, more rapid breathing to increase venous return to the heart.

30. What is the role of surfactant in respiratory regulation?

While surfactant doesn't directly regulate respiration, it plays a crucial role in maintaining lung function. Surfactant reduces surface tension in the alveoli, preventing them from collapsing and making it easier to inflate the lungs. This indirectly supports efficient gas exchange and reduces the work of breathing.

31. What is the regulation of respiration?

The regulation of respiration is the process by which the body controls breathing rate and depth to maintain optimal levels of oxygen and carbon dioxide in the blood. This involves complex interactions between the respiratory centers in the brain, chemoreceptors, and various physiological factors.

32. What are chemoreceptors and how do they influence respiration?

Chemoreceptors are specialized sensory cells that detect changes in blood chemistry, particularly CO2 levels, pH, and oxygen concentration. There are two main types: central chemoreceptors in the brain and peripheral chemoreceptors in the carotid and aortic bodies. They send signals to the respiratory centers to adjust breathing rate and depth based on the body's needs.

33. What is the Hering-Breuer reflex?

The Hering-Breuer reflex is a protective mechanism that prevents over-inflation of the lungs. Stretch receptors in the lungs send signals to the brain when the lungs are fully inflated, inhibiting further inhalation and triggering exhalation. This reflex helps maintain a regular breathing rhythm and protects the lungs from damage.

34. What is the role of the autonomic nervous system in respiratory regulation?

The autonomic nervous system plays a crucial role in respiratory regulation. The sympathetic nervous system can increase breathing rate and depth during times of stress or physical activity, while the parasympathetic nervous system can decrease respiratory rate during rest or relaxation.

35. How does the respiratory system respond to increased metabolic acid production?

When the body produces more metabolic acids (e.g., during intense exercise or in certain medical conditions), the respiratory system responds by increasing the rate and depth of breathing. This helps to expel more CO2, which in turn helps to balance blood pH by reducing carbonic acid levels in the blood.

36. How does carbon dioxide affect breathing rate?

Carbon dioxide is the primary stimulus for breathing. As CO2 levels in the blood increase, it forms carbonic acid, lowering blood pH. This change is detected by chemoreceptors, which signal the respiratory centers to increase breathing rate and depth, expelling more CO2 and restoring blood pH balance.

37. Why is oxygen less important than CO2 in regulating normal breathing?

While oxygen is crucial for survival, it plays a smaller role in regulating normal breathing compared to CO2. This is because the body's oxygen levels don't typically fluctuate as much as CO2 levels during regular activities. CO2 changes are more sensitive indicators of the body's metabolic needs and are more directly linked to blood pH regulation.

38. How does the body respond to increased levels of oxygen?

Interestingly, high levels of oxygen (hyperoxia) have less of an effect on breathing than low levels. In some cases, very high oxygen levels can actually slightly decrease ventilation, a phenomenon known as the "hyperoxic ventilatory decline." This is because the drive to breathe is more strongly influenced by CO2 levels and pH than by oxygen levels.

39. What is the relationship between respiratory regulation and acid-base balance?

Respiratory regulation plays a crucial role in maintaining acid-base balance. By controlling the amount of CO2 expelled from the body, the respiratory system can quickly adjust blood pH. Increased breathing rate and depth can reduce blood CO2 levels, making the blood less acidic, while decreased ventilation can have the opposite effect.

40. How do endocrine factors influence respiratory regulation?

Various hormones can affect respiratory regulation. For example, progesterone increases sensitivity to CO2, which is why women often experience increased breathing rates during pregnancy and the luteal phase of the menstrual cycle. Thyroid hormones can also increase metabolic rate and consequently respiratory rate.

41. What is the concept of respiratory reserve and how does it relate to respiratory regulation?

Respiratory reserve refers to the additional breathing capacity available beyond what is used during normal, quiet breathing. It includes both inspiratory and expiratory reserve volumes. This reserve is crucial for respiratory regulation as it allows the system to respond to increased demands, such as during exercise or in response to changes in blood chemistry, by increasing breathing depth and rate without immediately reaching physiological limits.

42. How does the concept of respiratory quotient (RQ) relate to respiratory regulation?

The respiratory quotient (RQ) is the ratio of CO2 produced to O2 consumed. While not directly involved in respiratory regulation, RQ provides information about the type of fuel being metabolized (carbohydrates, fats, or proteins), which can influence overall metabolic rate and consequently, respiratory demands. Understanding RQ can help interpret how the body is responding to different metabolic states.

43. What is the concept of respiratory alkalosis and how does the body compensate for it?

Respiratory alkalosis occurs when excessive breathing leads to a decrease in blood CO2 levels, making the blood more alkaline. The body compensates through several mechanisms: the kidneys excrete more bicarbonate to reduce blood pH, breathing rate is reduced through negative feedback to the respiratory centers, and there may be a shift of the oxygen dissociation curve, affecting oxygen delivery to tissues.

44. How does obesity affect respiratory regulation?

Obesity can significantly impact respiratory regulation. Excess weight on the chest and abdomen can restrict lung expansion, leading to reduced lung volumes. This can result in a rapid, shallow breathing pattern. Additionally, obesity is associated with increased risk of sleep apnea, where normal respiratory regulation during sleep is disrupted.

45. What is the relationship between respiratory regulation and thermoregulation?

Respiratory regulation and thermoregulation are interconnected. Increased body temperature can lead to an increase in breathing rate, which helps dissipate heat through the respiratory tract. Conversely, in very cold conditions, breathing rate may initially increase to support greater metabolic activity for heat production, but prolonged exposure can lead to a decrease in respiratory rate to conserve heat.

46. How does the respiratory system adapt to chronic hypoxia, such as living at high altitudes?

Adaptation to chronic hypoxia involves several changes in respiratory regulation. Initially, there's an increase in breathing rate and depth. Over time, the body increases red blood cell production to improve oxygen-carrying capacity. The sensitivity of peripheral chemoreceptors to low oxygen levels increases, and there may be changes in the brain's respiratory centers to optimize breathing patterns for the low-oxygen environment.

47. How does the respiratory system respond to changes in blood glucose levels?

While not as direct as its response to CO2 or O2, the respiratory system does respond to changes in blood glucose. Hypoglycemia (low blood sugar) can stimulate breathing, likely as part of a general stress response. Hyperglycemia (high blood sugar), particularly in uncontrolled diabetes, can lead to a deep, rapid breathing pattern known as Kussmaul breathing, as the body attempts to compensate for metabolic acidosis.

48. What is the role of neuromodulators in respiratory regulation?

Neuromodulators, such as serotonin, norepinephrine, and acetylcholine, play important roles in fine-tuning respiratory regulation. They can alter the excitability of neurons in the respiratory centers, change the sensitivity of chemoreceptors, and influence the strength of respiratory muscle contractions. This allows for subtle adjustments in breathing patterns in response to various physiological states and environmental conditions.

49. How does the respiratory system interact with the immune system in terms of regulation?

The respiratory and immune systems have complex interactions. Inflammatory mediators released during immune responses can affect breathing by causing bronchoconstriction or altering the sensitivity of airway receptors. Conversely, breathing patterns can influence immune function in the lungs, with deep breathing potentially enhancing the distribution of immune cells and removal of pathogens.

50. How does the respiratory system respond to changes in atmospheric pressure during air travel?

During air travel, the decrease in atmospheric pressure at high altitudes can lead to expansion of gases in body cavities, including the lungs. The respiratory system responds by slightly increasing breathing