Pulmonary Ventiliation Flashcards
What is pulmonary ventilation
The inflow and outflow of air between the atmosphere and alveoli
How is the thocic cage involved in pulmonary ventilation
It expands and contracts causing the lung volumes to increase and decrease respectively
What is intrapulmonary pressure and what law is it in accordance with im
When an increase in lung volume causes a decrease in pressure within the lungs or when the lungs decrease in volume and an increase in pressure occurs in the lungs
It is higher or lower than the atmospheric pressure - creating a gradient for air to flow through
Boyles law
What is the diaphragm responsible for in pulmonary ventilation
Pressure changes within the thoracic cavity during quiet breathing
What does the diaphragm seperate
The abdominal and thoracic cavities
What are the muscle attachemmets of the diaphragm and it’s ligaments and fascia
How do the diaphragm muscle fibres cause inspiration
When the diaphragm contracts the muscle fibres pull the central tendon downwards towards the abdomen
A continued contraction causes the ribs the move upwards and outwards and the diaphragm is now fixed on the abdominal contents and cannot descend any further
How does posture affect the biomechanics of pulmonary ventilation
A person with slumped posture shows an increase in intra-abdominal pressure making movement of the diaphragm difficult, leading to reduced lung capacity and inspiration flow
How many planes of movement does thoracic cage movement take place in
3 planes
Sagittal
Transverse
Vertical
How does the thoracic cage move in the vertical plane
During abdominal breathing it occurs due to piston action of the diaphragm which will descend during inspiration by active contraction and ascend during expiration
How does the thoracic cage move in the Sagittal plane during pulmonary ventilation
Through thoracic breathing
Thrusting forward of the sternum that is brought about by the pump handle action of the ribs
What is the pump handle action of the ribs
Anterior ribs move upwards in conjunction to the sternum, effectively increasing the anterior posterior diameter of the thoracic cage by 20%
Occurs at 3-6 ribs and results from rotation at the costotransverse and costovertebral joints
How does the thoracic cage move in the transverse plane during pulmonary ventilation
Occurs due to bucket gangle motion of ribs 2-10 and calliper action of ribs 7-10
What is the bucket handle movement of the ribs 2-10
Middle rib is lower than each of the ends so during inspiration the middle portion lifts upwards and outwards increasing the lateral diameter of the thocic cage
Associated with intercostal muscle contraction
What is calliper action of ribs 7-10
Occur at lower ribs due to shape of articular surfaces on the transverse facets of the costotransverse joints
The facets are flatter and face downwards medially and backwards
The gliding movements cause the front ends of the ribs to move upwards and backwards
What muscles are required during forced breathing
Accessory muscles
Inspiration = sternocloidmastoid, scalenes, pec major and minor, serratus anterior
Expiration = abs, ext and int oblique, rectus abdominus
What’s the role of intercostal muscles contraction in inspiration and expiration
Prevent intercostal tissue being drawn in or pushed out due to pressure changes
Maintain rigidity of intercostal spaces
Ext intercostals help lift ribs up and out
Int intercostals vary in role
What are the 3 intercostals muscles
External intercostal
Internal intercostal
Intercostales intimi
Where do the external intercostal muscles run
Fibres run downwards and forwards between adjacent rib margins
Anteriorly muscle fibres are replaced by ext intercostal membrane which connects the costal cartilages
Where do the internal intercostal muscle fibres run
The middle layer of intercostals, they run downwards and backwards, arising from the costal groove.
Posteriorly they are replaced by internal intercostal membrane
They run in opposite directions to the external intercostal muscles
What is the morphology of intercostales intimi
The innermost layer of intercostals
They may extend further than 1 rib
Run downwards and backwards
What nerve supplies the intercostal muscles and where does it run
Intercostal nerves T1-11
Between the intercostales intimi and internal intercostals runs the nuerovascular bundle
