Notes On Mechanism of Breathing - CBSE Class 11 Biology
Respiration involves breathing, external respiration, internal transport, internal respiration and cellular respiration.
 
Breathing is a two-step process. The first step is inspiration, and the second step is expiration.
 
External respiration involves diffusion of gases across the alveoli which are the primary sites of exchange of gases.
 
Internal respiration is the diffusion of O2 and CO2 between blood and tissues through haemoglobin.
 
Cellular respiration is the breakdown of organic molecules in the presence of O2 to produce ATP in the cell.
 
The volume of air inspired and expired by the lungs can be estimated by using a procedure called spirometry.
 
The volume of air inspired or expired during each normal breath is called tidal volume.
A healthy man can inspire or expire approximately six thousand to eight thousand millilitres of air per minute.
 
Inspiratory reserve volume is the additional volume of air a person can inspire by maximal inspiration. This averages from two thousand five hundred millilitres to three thousand millilitres.
 
Expiratory reserve volume is the additional volume of air a person can expire by maximal expiration. This averages from one thousand millilitres to one thousand one hundred millilitres.
 
The volume of air that remains in the lungs after maximal expiration is called the residual volume. This averages from one thousand one hundred millilitres to one thousand two hundred millilitres.
 
The total volume of air a person can inspire after normal expiration is his inspiratory capacity. This includes both tidal volume and inspiratory reserve volume.
 
The total volume of air a person can expire after normal inspiration is his expiratory capacity. This includes both tidal volume and expiratory reserve volume.
 
The volume of air that remains in the lungs after normal expiration is called functional residual capacity. This includes both expiratory reserve volume and residual volume.
 
The volume of maximal inspiration after forced expiration or volume of maximal expiration after forced inspiration is known as vital capacity. This includes expiratory reserve volume, tidal volume and inspiratory reserve volume. It is approximately three litres.
 
The total volume of air accommodated in the lungs after maximal inspiration is known as total lung capacity. This includes residual volume, expiratory reserve volume, tidal volume and inspiratory reserve volume. 

Summary

Respiration involves breathing, external respiration, internal transport, internal respiration and cellular respiration.
 
Breathing is a two-step process. The first step is inspiration, and the second step is expiration.
 
External respiration involves diffusion of gases across the alveoli which are the primary sites of exchange of gases.
 
Internal respiration is the diffusion of O2 and CO2 between blood and tissues through haemoglobin.
 
Cellular respiration is the breakdown of organic molecules in the presence of O2 to produce ATP in the cell.
 
The volume of air inspired and expired by the lungs can be estimated by using a procedure called spirometry.
 
The volume of air inspired or expired during each normal breath is called tidal volume.
A healthy man can inspire or expire approximately six thousand to eight thousand millilitres of air per minute.
 
Inspiratory reserve volume is the additional volume of air a person can inspire by maximal inspiration. This averages from two thousand five hundred millilitres to three thousand millilitres.
 
Expiratory reserve volume is the additional volume of air a person can expire by maximal expiration. This averages from one thousand millilitres to one thousand one hundred millilitres.
 
The volume of air that remains in the lungs after maximal expiration is called the residual volume. This averages from one thousand one hundred millilitres to one thousand two hundred millilitres.
 
The total volume of air a person can inspire after normal expiration is his inspiratory capacity. This includes both tidal volume and inspiratory reserve volume.
 
The total volume of air a person can expire after normal inspiration is his expiratory capacity. This includes both tidal volume and expiratory reserve volume.
 
The volume of air that remains in the lungs after normal expiration is called functional residual capacity. This includes both expiratory reserve volume and residual volume.
 
The volume of maximal inspiration after forced expiration or volume of maximal expiration after forced inspiration is known as vital capacity. This includes expiratory reserve volume, tidal volume and inspiratory reserve volume. It is approximately three litres.
 
The total volume of air accommodated in the lungs after maximal inspiration is known as total lung capacity. This includes residual volume, expiratory reserve volume, tidal volume and inspiratory reserve volume. 

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