Lecture 4: Mechanisms of Breathing Flashcards Preview

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Flashcards in Lecture 4: Mechanisms of Breathing Deck (21)
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1

Which dome of the diaphragm is higher and why?

The right due to the liver

2

What are the attachments of the diaphragm?

Xiphoid surface
Central tendon
Costal margin (inferior 6 ribs and costal cartilage)
Lumbar vertebra - right crus (L1-3/4) and left crus (L1-2/3 i.e. the median arcuate ligament, medial arcuate ligament and lateral arcuate ligament

3

What does the median arcuate ligament arch over?

The top of the aorta
Links the left and right crura

4

What does the medial arcuate ligament arch over?

The psoas major

5

What does the lateral arcuate ligament arch over?

Quadratus lumborum

6

At what level does the IVC pierce the diaphragm?

T8
Slightly to the right
Inside central tendon
Pulls on walls of IVC and opens it up

7

At what level does the oesophagus pierce the diaphragm?

T10
Posterior to central tendon
Slightly to the left
Fibres of right crus sling around it

8

What nerves are the diaphragm innervated by?

The phrenic nerve C3, 4, 5
Motor to all
Sensory to central part and to pericardium

9

Where is pain from the central diaphragm referred to?

C3, 4, 5 dermatomes over the neck and upper limb (phrenic nerve)

10

Where is pain from the peripheral diaphragm referred to?

Dermatomes of the thoracic wall (intercostal nerve)

11

What occurs when P(atm) = P(lungs)?

No movement of air

12

What occurs when P(atm) > P(lungs)?

Air moves into lungs (inspiration)
Increase volume
Decrease pressure

13

What occurs when P(atm)

Air moves out of lungs (expiration)
Decrease volume
Increase pressure

14

What is the main determinant of quiet respiration?

The diaphragm

15

During inspiration the diaphragm ___ and ___ the lungs.

During inspiration the diaphragm contracts and expands the lungs.

16

During expiration the diaphragm ___ and ___ the lungs.
___ of the lungs significantly contributes to expiration.

During expiration the diaphragm relaxes and collapses the lungs.
Elasticity of the lungs significantly contributes to expiration.

17

Describe the pump handle movement of the thoracic cage.

The intercostal muscles and ribs 2-6 pull the sternum forward and upward with expansion in the vertebrosternal plane, increasing AP dimension.

18

Describe the bucket handle movement of the thoracic cage.

Ribs 7 - 10 pull the ribs out laterally in the vertebrocondral plane increasing transverse diameter

19

Which accessory respiratory muscles expand the chest?

Scalene muscles
External intercostals
Internal intercostals (medial to costochondral junction)

20

Which accessory respiratory muscles collapse the chest?

Internal intercostals (lateral to costochondral junction)
Abdominal muscles

21

What are hiccups and why do they occur?

Quick inspirations
Spasmodic contractions of the diaphragm
Occur as a result of irritation of:
- neurons in the phrenic nerve
- the diaphragm muscle
- the respiratory centres in the brainstem