Breathing & Exchange of Gases PPT Biology Class 11

 Page 1


Breathing and 
Exchange of 
Gases
Page 2


Breathing and 
Exchange of 
Gases
Introduction
Oxygen Utilization
Organisms use oxygen (O ¢) to 
break down glucose, amino 
acids, and fatty acids to obtain 
energy for various activities.
Carbon Dioxide Release
Harmful carbon dioxide (CO ¢) is 
released during these catabolic 
reactions.
Gas Exchange Necessity
Cells require continuous 
oxygen supply and must 
release the CO ¢ they produce.
Breathing Definition
This exchange of atmospheric 
O ¢ with cellular CO ¢ is called 
b r e a t h i n g or r e s p i r a t i o n.
Physical Observation
Breathing can be observed as chest movements.
Page 3


Breathing and 
Exchange of 
Gases
Introduction
Oxygen Utilization
Organisms use oxygen (O ¢) to 
break down glucose, amino 
acids, and fatty acids to obtain 
energy for various activities.
Carbon Dioxide Release
Harmful carbon dioxide (CO ¢) is 
released during these catabolic 
reactions.
Gas Exchange Necessity
Cells require continuous 
oxygen supply and must 
release the CO ¢ they produce.
Breathing Definition
This exchange of atmospheric 
O ¢ with cellular CO ¢ is called 
b r e a t h i n g or r e s p i r a t i o n.
Physical Observation
Breathing can be observed as chest movements.
Respiratory Organs
Lower Invertebrates
Lower invertebrates like 
sponges, coelenterates, 
flatworms, etc. exchange O ¢ 
with CO ¢ by simple diffusion 
over their entire body surface.
Earthworms
Earthworms use their moist 
cuticle for respiration.
Insects
Insects have a network of tubes 
called tracheal tubes to 
transport atmospheric air 
within the body.
Page 4


Breathing and 
Exchange of 
Gases
Introduction
Oxygen Utilization
Organisms use oxygen (O ¢) to 
break down glucose, amino 
acids, and fatty acids to obtain 
energy for various activities.
Carbon Dioxide Release
Harmful carbon dioxide (CO ¢) is 
released during these catabolic 
reactions.
Gas Exchange Necessity
Cells require continuous 
oxygen supply and must 
release the CO ¢ they produce.
Breathing Definition
This exchange of atmospheric 
O ¢ with cellular CO ¢ is called 
b r e a t h i n g or r e s p i r a t i o n.
Physical Observation
Breathing can be observed as chest movements.
Respiratory Organs
Lower Invertebrates
Lower invertebrates like 
sponges, coelenterates, 
flatworms, etc. exchange O ¢ 
with CO ¢ by simple diffusion 
over their entire body surface.
Earthworms
Earthworms use their moist 
cuticle for respiration.
Insects
Insects have a network of tubes 
called tracheal tubes to 
transport atmospheric air 
within the body.
Respiratory Organs in different Organisms
Fishes
Fishes use gills for respiration, 
which are specialized organs 
that extract oxygen from water.
Terrestrial Vertebrates
Amphibians, reptiles, birds, 
and mammals respire through 
lungs, though their structure 
and complexity vary across 
species.
Amphibians
Frogs (amphibians) can also 
respire through their moist skin 
(cutaneous respiration), 
allowing gas exchange directly 
through the skin surface.
Page 5


Breathing and 
Exchange of 
Gases
Introduction
Oxygen Utilization
Organisms use oxygen (O ¢) to 
break down glucose, amino 
acids, and fatty acids to obtain 
energy for various activities.
Carbon Dioxide Release
Harmful carbon dioxide (CO ¢) is 
released during these catabolic 
reactions.
Gas Exchange Necessity
Cells require continuous 
oxygen supply and must 
release the CO ¢ they produce.
Breathing Definition
This exchange of atmospheric 
O ¢ with cellular CO ¢ is called 
b r e a t h i n g or r e s p i r a t i o n.
Physical Observation
Breathing can be observed as chest movements.
Respiratory Organs
Lower Invertebrates
Lower invertebrates like 
sponges, coelenterates, 
flatworms, etc. exchange O ¢ 
with CO ¢ by simple diffusion 
over their entire body surface.
Earthworms
Earthworms use their moist 
cuticle for respiration.
Insects
Insects have a network of tubes 
called tracheal tubes to 
transport atmospheric air 
within the body.
Respiratory Organs in different Organisms
Fishes
Fishes use gills for respiration, 
which are specialized organs 
that extract oxygen from water.
Terrestrial Vertebrates
Amphibians, reptiles, birds, 
and mammals respire through 
lungs, though their structure 
and complexity vary across 
species.
Amphibians
Frogs (amphibians) can also 
respire through their moist skin 
(cutaneous respiration), 
allowing gas exchange directly 
through the skin surface.
Human Respiratory System
External Nostrils
The human respiratory 
system starts with a pair 
of external nostrils 
opening out above the 
upper lips.
Nasal Chamber
It leads to a nasal 
chamber through the 
nasal passage.
Pharynx
The nasal chamber opens 
into the pharynx, a 
portion of which is the 
common passage for 
food and air.
Larynx
The pharynx opens 
through the larynx into 
the trachea. The larynx is 
a cartilaginous box which 
helps in sound production 
and is hence called the 
sound box.