# CBSE Class 11 Biology NCERT Solutions: Chapter 17, Breathing and Exchange of Gases

Aug 9, 2018 16:51 IST
Breathing and Exchange of Gases: NCERT Solutions

Here we are providing NCERT solutions for CBSE Class 11 Biology chapter – Breathing and Exchange of Gases. All these model solutions have been prepared by the subject experts. These solutions will help you find the right approach to solve the NCERT questions and understand the criteria to write perfect answers in exams to grab high scores.

Some prominent features of Class 11 Biology NCERT Solutions are:

• Each solution is designed to involve the appropriate concepts and terms.
• Solutions have been revised by subject experts to bring error free stuff.
• Each solution is designed as per the guidelines followed in CBSE marking schemes for board exams.

Students may download all the NCERT Solutions for CBSE Class 11 Biology chapter – Breathing and Exchange of Gases, in the form of PDF.

Some of the questions and their solutions from NCERT Solutions for Class 11: Breathing and Exchange of Gases, are as follows:

Q. Define vital capacity. What is its significance?

Ans. Vital capacity: The is the maximum volume of air that a person can exhale out after a maximum inspiration is called Vital Capacity. It is about 3.5 – 4.5 litres in a normal adult person.

Significance of Vital Capacity: It allows the intake of maximum amount of fresh air and to get rid of the foul air in a single stroke of respiration. Hence, it increases the gaseous exchange between the various tissues of the body, thereby increases the amount of energy available to the body.

Q. State the volume of air remaining in the lungs after a normal breathing.

Ans. The volume of air remaining in the lungs after a normal breathing is called Functional Residual Capacity (FRC). It can be measured as the sum of expiratory reserve volume (ERV) and residual volume (RV). The average value of functional residual capacity of the human lungs is about 2500 – 3000 mL.

CBSE Class 11 Biology Syllabus 2018 - 2019

Q. Diffusion of gases occurs in the alveolar region only and not in the other parts of respiratory system. Why?

Ans. Aalveolar region has characters suitable for the efficient exchange of gases. The gaseous exchange between the alveoli and the blood capillaries surrounding the alveoli, takes place by the process of diffusion because of pressure or concentration gradient. The highly-permeable and thin membrane of the alveoli is suitable for the diffusion of gases, while other parts of the respiratory system are not structured to serve this purpose. Hence, diffusion of gases occurs in the alveolar region only and not in the other parts of respiratory system.

Q. How is respiration regulated?

Ans. It is the respiratory rhythm centre present in the medulla region of the brain which regulates the respiration. The functions of the respiratory rhythm centre are moderated by the pneumotaxic centre present in the pons. Chemosensitive area which is situated adjacent to the rhythm centre, is highly sensitive to CO2 and H+ concentration. Increase in the concentration of these compounds can activate this chemosensitive area which in turn gives signal to the rhythm centre to change the rate of expiration for the elimination of these compounds.

The receptors present in the carotid artery and aorta can also detect the levels of carbon dioxide and hydrogen ions in blood. As the level of carbon dioxide increases, these receptors send signals to the rhythm centre to perform the corrective actions.

Get the complete the NCERT solutions for Class 11: Breathing and Exchange of Gases, from the following link:

Class 11 Biology NCERT Chapter: Breathing and Exchange of Gases

Before solving the questions given in the Class 11 Biology NCERT chapter- Breathing and Exchange of Gases, students should thoroughly read this chapter to grasp all the concepts explained in it. This will help you understand the problem discussed in a question and then come with an appropriate answer.

Main topics discussed in Class 11 Biology chapter: Breathing and Exchange of Gases are:

• Respiratory organs
• Human respiratory system
• Mechanism of breathing
• Respiratory volumes and capacities
• Exchange of gases

Transport of oxygen

Transport of carbon dioxide

• Regulation of respiration