biology class 10 the lungs mechanism of inhalation and exhalation

1. THE LUNGS
MECHANISM OF INHALATION AND
EXHALATION

2. THE LUNGS:
• Respiratory organ
• Two lungs (left lung and right lung)
small because it large because it
has two lobes has three lobes

3. LOCATION
Lungs are located in thoracic cavity.
What is thoracic cavity?
The thoracic cavity, also called the chest cavity, is
a cavity of vertebrates bounded by the rib cage on
the sides and top, and the diaphragm on the
bottom.

4. THORACIC CAVITY:
• There are 12 pairs of ribs
• Muscles between rib bones are called intercostal
muscles
• Thick muscular structure below the lungs is
known as diaphragm.

5. CHARACTERTISTICS OF LUNGS
• Lungs are spongy and elastic.
• Lungs have blood vessels.
• Blood vessels of lungs have a specific name that
is pulmonary arteries and pulmonary veins.

6. FUNCTION OF PLEURAL MEMBRANE:
• Each lung is enclosed by two membranes which
are
1.Outer pleural membrane
2.Inner pleural membrane
Membrane encloses a fluid which provides
lubrication for expansions
and contraction of lungs.

7. INHALATION EXHALATION
The intake of air from
environment into
lungs is known as
inhalation
The impure air is
expelled out from
lungs during
exhalation.

8. INHALATION EXHALATION
Rib muscles contract
and ribs are raised.
Pressure on lungs
reduces. As a result
the lungs expand.
Rib muscles relax and
ribs came in original
position.
Pressure on lungs
increases. As a result
lungs contract.

9. INHALATION EXHALATION
The air rushes into
lungs to equalize the
pressure on both
sides.
The dome-shaped
diaphragm contract
and is lowered.
The air expelled out
of lungs to equalize
the pressure on both
sides.
The diaphragm muscles
relax and it gets
raised dome shape.

11. Humans breathe 16-20 times per minute in
normal circumstances i.e. at rest.
During exercise or other hard physical works the
breathing rate increases up to 30-40 times per
minute.
The rate of breathing is controlled by respiratory
center in brain.