Mechanism on Respiration | Lecture Note

University:
The University Of Western Ontario
Course:
ANAT 2200B | Systemic Anatomy of the Human Body
Academic year:

2022
Views:

493

Pages:

3
Author:

Kyuwon J.

Mechanism on Respiration ● Air flow due to pressure gradient changes ● Pressure changes due to… ○ Thoracic volume change ■ Diaphragm ■ Rib movements ■ Accessory muscles ● Pump ○ Diaphragm ■ Main inspiratory muscles ■ Contraction and descends ■ Increase in vertical thoracic diameter ■ More negative intrathoracic pressure ● Air moves in ■ Increase in intra-abdominal pressure ● Abdominal contents displaced ○ Clinical ■ Diaphragm weakness ● Dyspnea tends to be worse lying flat ● Phrenic nerves C3-C5 injury ● Hemidiaphragm elevator for CXR ○ Rib movements ■ Expansion of thoracic cage ■ Pump handle movements ● Mainly for upper ribs ● Around 2-6 ● Rib and sternum will swing up and forward ● Increase in AP diameter ○ Thorax ● Costovertebral ● Sternocostal ■ Bucket handle movements ● Ribs moves up and down ● Transverse diameter ● Obvious at midaxillary lines ■ Caliper movements ● 11-12 ribs ● Swinging out ● Laterally floating ● Widening and lower thorax ○ Smaller contributions ● Intercostals ○ External intercostals ■ Elevation of ribs ■ Assist in inspirations ■ Stabilization of intercostal space ● During expansions ○ Internal intercostals ■ Interosseous part ● Depression of rib ● Forced expiration ■ Interchondral part ● Assist in inspiration ● Cartilage regions ○ Innermost intercostals ■ Internal intercostal involvements ■ Important since neurovascular plane is between internal and innermost