Pulmonary Ventiliation

Question 1

What is pulmonary ventilation

Answer 1

The inflow and outflow of air between the atmosphere and alveoli

Question 2

How is the thocic cage involved in pulmonary ventilation

Answer 2

It expands and contracts causing the lung volumes to increase and decrease respectively

Question 3

What is intrapulmonary pressure and what law is it in accordance with im

Answer 3

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

Question 4

What is the diaphragm responsible for in pulmonary ventilation

Answer 4

Pressure changes within the thoracic cavity during quiet breathing

Question 5

What does the diaphragm seperate

Answer 5

The abdominal and thoracic cavities

Question 6

What are the muscle attachemmets of the diaphragm and it’s ligaments and fascia

Question 7

How do the diaphragm muscle fibres cause inspiration

Answer 7

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

Question 8

How does posture affect the biomechanics of pulmonary ventilation

Answer 8

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

Question 9

How many planes of movement does thoracic cage movement take place in

Answer 9

3 planes
Sagittal
Transverse
Vertical

Question 10

How does the thoracic cage move in the vertical plane

Answer 10

During abdominal breathing it occurs due to piston action of the diaphragm which will descend during inspiration by active contraction and ascend during expiration

Question 11

How does the thoracic cage move in the Sagittal plane during pulmonary ventilation

Answer 11

Through thoracic breathing
Thrusting forward of the sternum that is brought about by the pump handle action of the ribs

Question 12

What is the pump handle action of the ribs

Answer 12

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

Question 13

How does the thoracic cage move in the transverse plane during pulmonary ventilation

Answer 13

Occurs due to bucket gangle motion of ribs 2-10 and calliper action of ribs 7-10

Question 14

What is the bucket handle movement of the ribs 2-10

Answer 14

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

Question 15

What is calliper action of ribs 7-10

Answer 15

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

Question 16

What muscles are required during forced breathing

Answer 16

Accessory muscles
Inspiration = sternocloidmastoid, scalenes, pec major and minor, serratus anterior
Expiration = abs, ext and int oblique, rectus abdominus

Question 17

What’s the role of intercostal muscles contraction in inspiration and expiration

Answer 17

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

Question 18

What are the 3 intercostals muscles

Answer 18

External intercostal
Internal intercostal
Intercostales intimi

Question 19

Where do the external intercostal muscles run

Answer 19

Fibres run downwards and forwards between adjacent rib margins
Anteriorly muscle fibres are replaced by ext intercostal membrane which connects the costal cartilages

Question 20

Where do the internal intercostal muscle fibres run

Answer 20

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

Question 21

What is the morphology of intercostales intimi

Answer 21

The innermost layer of intercostals
They may extend further than 1 rib
Run downwards and backwards

Question 22

What nerve supplies the intercostal muscles and where does it run

Answer 22

Intercostal nerves T1-11
Between the intercostales intimi and internal intercostals runs the nuerovascular bundle