ANAT30008 Mechanisms of Breathing_Diaphragm.pdf

Diaphragm; Mechanisms of Breathing Professor Jason Ivanusic Room E724 7th Floor, East Wing, Medical Building Email: [email protected] Phone: 83447254  WARNING This material has been provided to you pursuant to section 49 of the Copy...

Diaphragm; Mechanisms of Breathing Professor Jason Ivanusic Room E724 7th Floor, East Wing, Medical Building Email: [email protected] Phone: 83447254  WARNING This material has been provided to you pursuant to section 49 of the Copyright Act 1968 (the Act) for the purposes of research or study. The contents of the material may be subject to copyright protection under the Act. Further dealings by you with this material may be a copyright infringement. To determine whether such a communication would be an infringement, it is necessary to have regard to the criteria set out in Part 3, Division 3 of the Act.  Diaphragm Curves downward at periphery RIGHT LEFT DOME DOME (higher) (lower) Central tendon Netter, F.H. Interactive Atlas of Human Anatomy. 3rd ed. New Jersey, Icon Learning Systems, 2003, ISBN: 1-929007- 15-9, Plate #180  Xiphoid process Central tendon Attachments of Costal margin diaphragm (inferior six ribs and costal cartilages) Median arcuate ligament Medial arcuate ligament (over psoas major) Lateral arcuate ligament (over Lumbar vertebra via quadratus left crus (L1-2/3) lumborum) Lumbar vertebra via Right crus Netter, F.H. Interactive Atlas of Human Anatomy. 3rd ed. New Jersey, Icon (L1-3/4) Learning Systems, 2003, ISBN: 1-929007-15-9, Plate #181 Structures that pierce Inferior the diaphragm Vena Cava T1 T2 Oesophagus T3 T4 Aorta T5 T6 T7 T8 T9 T10 IVC (T8) T11 T12 Oesophagus (T10) Netter, F.H. Interactive Atlas of Human Anatomy. 3rd ed. New Jersey, Icon Learning Systems, 2003, ISBN: 1-929007-15-9, Plate #181 Aorta (T12) Author’s own  Left Phrenic Right Phrenic nerve nerve Hemiazygous Azygous Vein Vein Sympathetic trunk Sphlancnic nerves Netter, F.H. Interactive Atlas of Human Anatomy. 3rd ed. New Jersey, Icon Learning Systems, 2003, ISBN: 1-929007-15-9, Plate #181  Pain from the central diaphragm is referred to C3, 4 and 5 dermatomes over the neck and upper limb (phrenic nerve) Innervation of Pain from the peripheral diaphragm is referred to Diaphragm dermatomes of the thoracic wall (intercostal nerves). Phrenic Nerve C 3,4,5 Anterior to root of lung Motor to all of diaphragm Left Phrenic Sensory to central part nerve of diaphragm Sensory to Lower intercostal pericardium nerves Sensory to periphery of Diaphragm Right Phrenic nerve Netter, F.H. Interactive Atlas of Human Anatomy. 3rd ed. New Jersey, Icon Learning Systems, 2003, ISBN: 1-929007-15-9, Plate #182A Mechanisms of breathing  Movement of air in and out of lungs Air moves from areas of high pressure to areas of low pressure If P(atm) = P(lungs) Then no movement of air Author’s own  Movement of air in and out of lungs Air moves from areas of high pressure to areas of low pressure to equalize pressures If P(atm) > P(lungs) Then air moves into lung Author’s own  Movement of air in and out of lungs Air moves from areas of high pressure to areas of low pressure In order for us to move air in and out of our lungs, we must change the pressure gradient between our lungs and the atmosphere If P(atm) < P(lungs) Then air moves out of lung Author’s own  Author’s own We can change the pressure in our lungs by altering its volume because pressure is inversely proportional to volume Inspiration Expiration Increase volume Decrease volume Decrease pressure Increase pressure P(atm) = P(lungs) P(atm) > P(lungs) P(atm) < P(lungs) No movement of air Air moves into lung Air moves out of lung  So how do we expand and collapse our lungs to change the pressure within? Parietal pleura Pleural cavity Visceral pleura Author’s own  Parietal pleura firmly attached to thoracic cage (including the diaphragm) Movements of thoracic cage and diaphragm result in movements of parietal pleura,visceral pleura (surface tension of fluid in pleural cavity) and lungs Diaphragm Ribs Author’s own  Author’s own Diaphragm Main determinant of quiet respiration Inspiration Expiration Diaphragm contracts Diaphragm relaxes Expands lungs Collapses lungs Thoracic cavity Elasticity of lungs contributes significantly to expiration Rhythmic contractions controlled by Diaphragm respiratory centre of brainstem Movements of the thoracic cage Modified from Drake R L, Vogl W, Mitchell A W M. Gray’s Anatomy For Students. Churchill Livingstone; 2005. ISBN 0808923064. p.136 fig. 3.34  Accessory respiratory muscles Expand Collapse Scalene muscles Internal intercostals External intercostals (lateral to costochondral junction) Internal intercostals (medial to costochondral junction) Abdominal muscles Netter, F.H. Interactive Atlas of Human Anatomy. 3rd ed. New Jersey, Icon Learning Systems, 2003, ISBN: 1- 929007-15-9, Plate #183  Subclavius Clavicle Coracoid anchors clavicle Process Pectoralis Major (clavicular head) Pectoralis Humerus Minor (medial) Elevates ribs/ Pectoralis stabilizes Major scapula (sternal head) Adducts arm Author’s own  Serratus Anterior Protracts scapula Medial border of anterior surface of scapula Lateral aspect of ribs 1-8 Author’s own Hiccups Quick inspirations Spasmodic contractions of diaphragm Irritation of: neurons in the phrenic nerve the diaphragm muscle itself the respiratory centres in the brainstem Image from: http://www.grupthink.com/poll/487