Class 11 Biology - CBSE
Breathing and Exchange of Gases
The chapter 'Breathing and Exchange of Gases' in Class 11 Biology explores the physiological mechanisms of respiration in humans. It covers the respiratory organs, the step-by-step process of pulmonary ventilation, the mechanisms of gas exchange in the alveoli and tissues, and the transport of oxygen and carbon dioxide by blood. You will also learn about the regulation of respiration by neural centers and common respiratory disorders like asthma and emphysema. This chapter is vital for CBSE board exams as it tests both conceptual understanding and diagram-based questions, carrying significant weight in the human physiology unit.
Start Learning FreeKey Concepts
Respiratory Organs
Different animals use different organs for respiration depending on their habitats and levels of organization, such as skin in earthworms, tracheae in insects, gills in aquatic animals, and lungs in terrestrial vertebrates.
Mechanism of Breathing
Breathing involves inspiration and expiration, driven by pressure gradients created by the contraction and relaxation of the diaphragm and intercostal muscles.
Exchange of Gases
Gases diffuse across the respiratory membrane from regions of higher partial pressure to lower partial pressure, occurring primarily between alveoli and pulmonary blood capillaries, and between blood and tissues.
Transport of Gases
Oxygen is primarily transported as oxyhemoglobin bound to red blood cells, while carbon dioxide is transported as bicarbonate ions, dissolved in plasma, or bound to hemoglobin as carbaminohemoglobin.
Regulation of Respiration
The respiratory rhythm is primarily regulated by the respiratory rhythm center in the medulla oblongata, with the pneumotaxic center in the pons moderating its functions.
Important Formulas
Board Exam Info
In the CBSE Class 11 Biology examination, this chapter is part of the Human Physiology unit, which typically carries around 12-15 marks in total. Questions from this chapter frequently include diagram labeling (such as the human respiratory system or oxygen dissociation curve), differentiation questions (like IRV vs ERV), and application-based short or long answer questions.
Frequently Asked Questions
What is the difference between breathing and respiration?
Breathing is the physical process of inhaling oxygen and exhaling carbon dioxide, whereas respiration is a biochemical process where cells oxidize glucose to release energy in the form of ATP.
Why does the oxygen-hemoglobin dissociation curve shift to the right during exercise?
During exercise, tissues have higher carbon dioxide, higher temperature, and lower pH (Bohr effect), which reduces hemoglobin's affinity for oxygen and shifts the curve to the right, releasing more oxygen to the active tissues.
What is the role of the diaphragm in breathing?
The diaphragm is a dome-shaped muscular partition that contracts and flattens during inspiration to increase the volume of the thoracic cavity, decreasing pressure and pulling air into the lungs.
Learn Breathing and Exchange of Gases with Your AI Tutor
10 different ways to study this chapter. Free for 3 chapters per day.
Lecture
Key Points
Interactive
Quiz
Flashcards