Breathing and Exchange of Gases
Breathing and gas exchange are two very important physiological activities in which oxygen enters an organism and carbon dioxide leaves it. Questions regarding this mechanism form a daily feature in any of the entrance examinations like NEET, JEE, and AIIMS. Hence, this chapter is highly important for any student studying biology. It forms an integral part of the biology curriculum that caters to the ground-level knowledge necessary for subsequent study in physiology and health sciences.
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- Introduction to Breathing and Exchange of Gases
- Key Components of Breathing and Exchange of Gases
- Breathing Mechanism
- Respiratory Volumes and Capacities
- Regulation of Respiration
- Respiratory System Diseases
- Transportation Mechanisms for Gases
- Oxygen Dissociation Curve
- More Resources
- Important Topics in Breathing and Exchange of Gases for Different Entrance Exams
- Weightage of Topics in Breathing and Exchange of Gases Across Different Entrance Exams
- Tips, Tricks, and Strategies to Prepare for Breathing and Exchange of Gases
- Types of Questions Asked on Breathing and Exchange of Gases in Different Exams
- Recommended videos on Breathing and Exchange of Gases
Introduction to Breathing and Exchange of Gases
Breathing is an essential biological activity that allows organisms to take in oxygen and give out carbon dioxide. The structures that make up this process are the nostrils, pharynx, larynx, trachea, bronchi, bronchioles, and alveoli. In class 11, these constituent parts are detailed by showing that air reaches different parts of the system and how gas exchanges occur in the alveoli.
Also Read:
- Practice MCQ on "Mechanism of Breathing"
- Body Fluids And Circulation
- Respiration in plants
- Larynx
- Vocal Cord - The Source of Human Voice
Key Components of Breathing and Exchange of Gases
The key components are stated below:
Component | Function |
Nostrils | The entry point for air; filters dust with hair follicles. |
Pharynx | Common passage for air and food; prevents food from entering the larynx. |
Larynx | Known as the soundbox; contains vocal cords and is protected by the epiglottis. |
Trachea | Windpipe that divides into primary bronchi; supported by C-shaped cartilaginous rings. |
Bronchi & Bronchioles | Branching tubes that lead to alveoli; responsible for air distribution. |
Alveoli | Microscopic sacs where gas exchange occurs; surrounded by capillaries. |
NCERT Notes Subject Wise Link:
Breathing Mechanism
Inspiration: This is when air enters; resulting in lowered intrapulmonary pressure due to contraction of the diaphragm and the intercostal muscles elevating the ribs.
Expiration: Alveolar air is expelled when intrapulmonary pressure rises when the muscles relax.
NCERT Solutions Subject-wise link:
Respiratory Volumes and Capacities
Volume/Capacity | Measurement (ml) | Description |
Tidal Volume (TV) | 500 ml | Normal inhalation/exhalation |
Inspiratory Reserve Volume (IRV) | 2500-3000 ml | Extra air inhaled |
Expiratory Reserve Volume (ERV) | 1000-1100 ml | Extra air exhaled |
Residual Volume (RV) | 1100-1200 ml | Air remaining after forced expiration |
Vital Capacity (VC) | TV + IRV + ERV | Maximum air breathed in/out |
Total Lung Capacity (TLC) | VC + RV | Total lung capacity |
NCERT Exemplar Solutions Subject-wise link:
Regulation of Respiration
Respiration is regulated by the medulla oblongata and pons based on the requirements for oxygen.
Aspect | Description |
Primary Control Centers | The medulla oblongata and pons regulate respiration based on oxygen requirements. |
Respiratory Rhythm Center | Located in the medulla, it generates the basic rhythm of breathing. |
Pneumotaxic Center | Found in the upper pons, it modulates the rhythm by reducing the duration of inspiration. |
Chemosensitive Area | Sensitive to levels of carbon dioxide (CO₂) and hydrogen ions (H⁺), signalling changes in expiration rates. |
Receptors | Chemoreceptors in the carotid artery and aorta detect blood levels of CO₂ and H⁺ ions. |
Feedback Mechanism | Elevated CO₂ levels trigger increased respiratory activity to maintain oxygen supply and remove CO₂. |
Voluntary Control | Respiration can be voluntarily controlled through higher brain centres for activities like speaking or breath-holding. |
NCERT Books Link:
Respiratory System Diseases
The different Respiratory System Diseases are:
Disorder | Description |
Asthma | Inflammation of the airways leads to wheezing. |
Emphysema | Damage to alveolar walls causing shortness of breath. |
Occupational Lung Diseases | Long-term exposure leads to fibrosis. |
Transportation Mechanisms for Gases
Oxygen is primarily bound to haemoglobin in red blood cells, while carbon dioxide is transported in solution in plasma or as bicarbonate ions.
Oxygen Dissociation Curve
One molecule of haemoglobin binds with oxygen molecules. The binding of haemoglobin with oxygen relies upon:
The partial strain of oxygen.
The partial strain of carbon dioxide.
H+ ion concentration.
Temperature.
When the shared saturation of haemoglobin is plotted towards the partial oxygen then the curve is known as oxygen dissociation.
In low temperature, excessive partial oxygen, low partial carbon dioxide, much less H+ ion concentration (acidic pH), the curve in the direction of the proper suggests the formation of oxyhemoglobin, while in low partial oxygen, excessive carbon dioxide, primary pH, excessive-temperature the curve shifts in the direction of the left, which suggests the dissociation of oxygen with haemoglobin.
More Resources
For all study materials download the PDF of class 11 on respiration and exchange of gases.
Find the previous year questions (PYQ) on the topic of respiration and exchange of gases for NEET preparation.
Understand the MCQs on breathing and exchange of gases to assess your knowledge.
Refer to the resources and download the free PDF for class 11 breathing and exchange of gases.
Important Topics in Breathing and Exchange of Gases for Different Entrance Exams
Here’s a table highlighting key topics related to the breathing and exchange of gases that are commonly covered in various entrance exams:
Topic | NEET | JEE | AIIMS | State-Level Exams |
High | Medium | High | Medium | |
High | Medium | High | Medium | |
High | Medium | High | Medium | |
Medium | Low | Medium | Low | |
High | Low | High | Medium | |
Medium | Low | Medium | Low |
These topics are crucial for students preparing for NEET, JEE, AIIMS, and state-level exams, as they encompass fundamental concepts in the study of the respiratory system and gas exchange.
Weightage of Topics in Breathing and Exchange of Gases Across Different Entrance Exams
The following table shows the weightage of topics related to breathing and gas exchange across various entrance exams:
Topic | NEET | JEE | AIIMS | State-Level Exams |
Breathing Mechanism | 25% | 20% | 30% | 25% |
Gas Exchange in Alveoli | 30% | 25% | 30% | 20% |
Role of Hemoglobin | 20% | 15% | 20% | 15% |
Respiratory Volumes | 15% | 10% | 10% | 10% |
Regulation of Breathing | 10% | 10% | 10% | 10% |
Tips, Tricks, and Strategies to Prepare for Breathing and Exchange of Gases
Here are some effective tips, tricks, and strategies to help you prepare for the topic of breathing and exchange of gases, along with useful mnemonics:
Tips and Strategies | Description |
Understand Key Concepts | Focus on the mechanisms of breathing, gas exchange, and the role of alveoli. |
Use Mnemonics | - "I Breathe O2, I Exhale CO2": Remember the basic process of respiration. - "A B C": Alveoli for gas exchange, Breathing for inhalation/exhalation, Circulation for transport in blood. |
Practice with Diagrams | Draw diagrams illustrating the respiratory system and gas exchange processes. |
Solve Previous Year Questions | Review past NEET and JEE questions related to breathing and exchange of gases. |
Flashcards for Terminology | Create flashcards for key terms like tidal volume, vital capacity, and diffusion. |
Regular Revision | Schedule regular review sessions to reinforce knowledge and improve retention. |
Types of Questions Asked on Breathing and Exchange of Gases in Different Exams
Here’s a summary of the types of questions you can expect regarding breathing and gas exchange across different exams:
Understanding the processes involved in breathing and the exchange of gases is very essential in trying to understand how bodies work during respiration. This knowledge assists in academic studies and increases awareness of respiratory health and diseases. Students can, therefore, have access to resources such as PDFs on breathing and exchange of gases that offer free downloads for materials used for class 11.
By focusing on these essential elements and processes, the students will be well-equipped to tackle these tests as NEET, JEE, and AIIMS. In parallel, the knowledge bank thus gained will enrich their perception of human physiology concerning respiration and exchange of gases.
Also read:
Recommended videos on Breathing and Exchange of Gases
Breathing and Cellular Respiration
The Lungs and Thoracic Chamber
Overview of the Process of Respiration
Frequently Asked Questions (FAQs)
The oxygen content material of the environment decreases with a boom in altitude. As a result, every breath a person takes upward offers him much less oxygen. The quantity of oxygen withinside the blood reduces as a result. The respiration fee will increase in reaction to a loss of oxygen. The oxygen content material of the blood. At an equal time, the frequency of the heartbeat will increase with a purpose to boom the oxygen delivery to the blood.
The middle of the respiratory rhythm, positioned withinside the vicinity of the medulla of the brain, is frequently chargeable for regulating the respiratory. The pneumatic middle can alternate the feature of the respiration rhythm middle with the aid of sending alerts to lessen the inspiratory fee. The chemosensitive location is close to the respiration middle. It is touchy to carbon dioxide and hydrogen ions. This vicinity sends alerts to alternate the expiratory fee to do away with connections.
Receptors withinside the carotid artery and aorta file the concentrations of carbon dioxide and hydrogen ions withinside the blood. As the carbon dioxide degree rises, the respiration middle sends nerve impulses for the important changes.
Insects have a trachea machine that contains a community of tubes. The change of gases happens via the trachea machine. Spiracles are the small openings at the aspect of the insect’s frame that are chargeable for soaking up oxygen-wealthy air in the frame. The spiracles are related to the trachea. The oxygen is then transported to the trachea through spiracles. The oxygen begins off evolved defusing withinside the frame. Whereas, carbon dioxide takes the opposite path. From the molecule of the frame, it travels to the tracheas and exits from the spiracles.
1. Breathing or pulmonary airflow with the aid of oxygen from the atmospheric air is drawn internal and carbon dioxide-wealthy alveolar air is launched out.
2. Diffusion of each oxygen and carbon dioxide throughout the alveolar membrane.
3. Gases are transported at some stage in the frame cells with the aid of using the blood.
4. Diffusion of oxygen and carbon dioxide among blood and tissues of the frame.
5. The cells make use of oxygen for catabolic reactions, ensuing withinside the launch of carbon dioxide.
The most quantity of air a person breathes in after a pressured expiration is known as critical ability. Vital ability is better for athletes and singers. Vital ability indicates the power of our idea and expiration.
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