1 Mechanisms of Ventilation

Question 1

What does the respiratory system consist of?

Answer 1

Nose and nasal cavity, pharynx, larynx, trachea, and lungs

Question 2

What types of ribs are there (and how many of these are there?)

Answer 2

True (1-7), False (8-10), Floating (11-12)

Question 3

What is pleura?

Answer 3

A serous membrane that surrounds the lung, containing pleural cavities. 2 types, separated by serous fluid.

Question 4

Name the two pleural

Answer 4

Parietal and Visceral

Question 5

Define Parietal pleura

Answer 5

The outer layer; lines the thoracic cavity

Question 6

Define visceral pleura

Answer 6

The inner layer covers lung and follows the lung fissures

Question 7

What is the upper respiratory tract made up of?

Answer 7

Nasal cavity, pharynx, larynx (epiglottis), trachea

Question 8

Name the 3 parts of the pharynx

Answer 8

Nasopharynx, oropharynx, laryngopharynx

Question 9

Role of epiglottis

Answer 9

Closes off the trachea when food is being swallowed, preventing it from entering the lungs. (It flattens posteriorly when food enters)

Question 10

List the stages of respiration/breathing

Answer 10

At rest, the diaphragm is relaxed (dome-shaped)

Muscles of respiration contract + expand thoracic cavity - mainly diaphragm (flat)

This increases thoracic volume and decreases intra-thoracic pressure

Air is drawn into lungs from outside (where pressure is greater)

Air passes into terminal bronchioles + alveoli to oxygenate blood

The diaphragm relaxes (dome), lung recoils, thoracic volume decreases, intra-thoracic pressure increases, and the air is expelled

Question 11

How does the thoracic cage interact with and expand the lungs

Answer 11

When the thoracic cage expands, so does the parietal pleura, which pulls the visceral pleura (and hence the lungs), thus expanding the lungs

Question 12

What is the most important muscle in respiration?

Answer 12

The diaphragm; dome-shaped, which separates the thorax and the abdomen

Question 13

What is the innervation of the diaphragm?

Answer 13

Phrenic nerve (C3,4,5 - keeps diaphragm alive)

Question 14

List the attachments of the diaphragm

Answer 14

Anteriorly: xiphoid process and costal margin
Laterally: ribs 6-12
Posteriorly: T12 Vertebrae

Question 15

What are intercostal muscles

Answer 15

Muscles which assist in inspiration and expiration, and have obliquely angled fibres from rib to rib

Question 16

What is the role of the external intercostal muscles?

Answer 16

Contraction of external muscles raises each rib toward the rib above (RAISE RIBCAGE)
[face inwards]

Question 17

What is the role of internal and innermost intercostal muscles?

Answer 17

Contraction of internal and innermost fibres depresses each rib toward the rib above
(LOWERS RIBCAGE)
[face outwards]

Question 18

Name the accessory muscles of respiration + list their actions

Answer 18

• Sternocleidomastoid (SCM) muscle raises sternum
• Scalene muscles prevent rib 1 + 2 from descending
• Pecs and trapezius ‘fix’ pectoral girdle to raise rib cage

Question 19

What is the movement of the rib cage during forced inspiration?

Answer 19

Upwards + Outwards

Question 20

What is the movement of the rib cage during forced expiration?

Answer 20

Downwards and Inwards

Question 21

Where are the ribs joined to?

Answer 21

The vertebral body and transverse process of vertebra

Question 22

What movement do the ribs follow?

Answer 22

Bucket and pump handle movement

• Up movement = bucket handle
• Out movement = pump handle

Question 23

List features of breathing in babies

Answer 23

Babies can only breathe via abdominal breathing:
- Newborn ribs are more horizontal, so can’t use pump/bucket handle movements
- Intercostal muscles are weak
This abdominal breathing is done by contracting the diaphragm

Question 24

Why is there a high risk for respiratory failure in babies

Answer 24

Reliance on the diaphragm alone means if it cannot contract, there will be respiratory failure

Question 25

List features of breathing in children:

that are different from breathing in adults

Answer 25

• Nasal breathers until 4-6 weeks
• Short neck and shorter/narrower airway = more susceptible to airway obstruction
• Tongue is longer in proportion to the mouth = more likely to obstruct if the child is unconscious
• Smaller lung capacity + underdeveloped chest muscles
• Have a higher respiratory rate
  (newborns - 60 breaths/min
  early teens - 20/30 breaths/min)

Question 26

What is used for the examination of the airways?

Answer 26

Bronchoscopy

Question 27

What is a sign of respiratory distress? (and why)

Answer 27

Use of accessory muscles whilst at rest to breathe

- As lungs fail to provide enough oxygen to a person’s body

Question 28

List some clinical problems associated with the respiratory system

Answer 28

Asthma
Emphysema/COPD
Lung Tumour
Pneumothorax