mechanism of respiration

1. Mechanism of Respiration
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3. Mechanism of Respiration

4. Contents of PPT
• 1) Mechanism of Respiration
• 2) 2 Stages of Respiration
• 3) Muscles of Respiration
• 4) Bucket Handle movement of ribs
• 5) Pump Handle movement of Sternum
• 6) Role of Expiratory Muscles
• 7) Role of Accessory Muscles

5. Mechanism of Respiration
• 2 Stages of Respiration –
• i) Inspiration = Intake of Atmosphere air
• ii) Expiration = Giving out of Alveolar air
• RR = 14 to 18 / min .This is brought about by
Muscles of Respiration

6. Muscles of Respiration
• Muscles of inspiration = a) Diaphragm b)
External Intercostal Muscles
• Muscles of Expiration = a) Internal Intercostal
Muscles b) Abdominal muscles
• Accessory muscles of Respiration =
• a) Levator Scapulae
• b) Sternomastoid
• c) Scaleni
• d) Muscles of Nostril ( Ala Nasi)

7. Muscles of Respiration
Intercostal Muscles Diaphragm

8. Accessory muscles of Respiration
Muscles of Nostril ( Ala Nasi) Muscles of Nostril ( Ala Nasi)

9. Accessory muscles of Respiration
Scaleni Sternocleidomastoid

10. Accessory muscles of Respiration-
Levator Scapulae

11. Inspiration & Expiration
• During quiet respiration ,Inspiration is active (
Due to contraction of muscles of Respiration)
• Expiration is Passive ( Due to Relaxation of
Muscles of Respiration )
• In quiet breathing – Expiratory muscles &
Accessory muscles have No role ( They work
only during Exercise –when Ventilation is to be
increased )

12. Diaphragm
• Chief Muscle of Respiration
• Membranous muscle ,which separates
abdomen & thorax
• Originates from Xiphisternum ,Costal
cartilages & Vertebrae .Supplied by
Phrenic Nerves

13. Diaphragm –Action
• Dome shaped muscle .When it contracts
,dome is lowered .Verticle diameter of chest
increases – Volume of chest increases – Intra
Thoracic Pressure falls – Inspiration takes
place ( Air moves from Higher Pressure to
Lower pressure )
• When Diaphragm relaxes ,Expiration occurs
passively

15.  Rib movement.
 1 Pump
handle
movement.(2-
6th)
 2 Bucket
handle
movement.(7-10th)
 Contraction of
external intercostal
muscles.

16. b) External Intercostal Muscles
• Present outer side of ribs ,directed downward
,forward & medially
• Supplied by Intercostal nerves
• When they contract – bring about 2 types of
movements as follows –
• i) Bucket Handle Movement of Ribs
• ii) Pump handle movement of Sternum

17. Bucket Handle movement of ribs
• Normally ribs are oblique .When External
intercostals muscles contract --- Oblique ribs are
elevated – they become horizontal – Transverse
diameter of chest increases – volume of chest
increases --- Intra Thoracic pressure falls –
Inspiration takes place
• When muscle relax – ribs again become oblique &
expiration occurs passively
• This movement is seen in lower ribs –Movement is
like handle of bucket

18. Bucket Handle movement of ribs

19. Pump Handle movement of Sternum
• When oblique ribs become horizontal ,they
push body of Sternum anterior --- AP
Diameter of chest increases – Intra Thoracic
pressure falls – Inspiration takes place
• When ribs become oblique again – Sternum
moves posterior & Expiration occurs
• This movement of body of Sternum on
Manubrium is called Pump Handle Movement

20. Pump Handle movement of Sternum

21. 2) Role of Expiratory Muscles –
• Internal Intercostal muscles ,when contract –
they make ribs Oblique & Forceful Expiration
occurs
• When abdominal muscles contract –Intra
abdominal pressure is raised – Diaphragm
moves up & forceful Expiration occurs

22. 3) Role of Accessory Muscles
• Most of these muscles are attached to Inlet of
chest
• When they contract – Upper ribs & clavicle is
elevated + Nostrils also open widely ---
Ventilation is enhanced
• Note – Expiratory & Accessory muscles work
only during Exercise

23. Suripto, Spd -- SMANSA