S1) Anatomy of the Respiratory System Flashcards
(87 cards)
1
Q
How does the respiratory system develop?
A
- Develops as a ‘diverticulum’ from the pharynx on the anterior side of the primitive gut tube.
- This elongates, bifurcates and branches to form the respiratory system
2
Q
Identify 5 functions of the nasal cavity
A
- Induce turbulent flow (nasal conchae)
- Warm and moisten inspired air
- Recover water from expired air
- Speech production (phonation)
- Olfaction
3
Q
Briefly describe the purpose of the paranasal sinuses
A
- made up of the larynx and the pharynx
Complement the function of the nasal cavity
4
Q
What are the three divisions of the pharynx? and the overall role of the pharynx
A
- Nasopharynx
- Oropharynx
- Laryngopharynx
5
Q
Explain the relationship between the pharynx and larynx
A
The pharynx and larynx work together to ensure that food and air enter the oesophagus and trachea respectively
6
Q
How does the larynx protect the airway during swallowing?
A
The epiglottis is a flap made of elastic cartilage attached to the entrance of the larynx which projects obliquely upwards to prevent the aspiration of food/liquids during swallowing and blocks the trachea
→ laryngeal inlet becomes narrowed when epiglottis folds, vocal chords adduct and shut
7
Q
Identify the 6 structures in the conducting zone of the respiratory system
A
- Trachea
- Primary (main) bronchi
- Secondary (lobar) bronchi
- Tertiary (segmental) bronchi
- Bronchioles
- Terminal bronchioles
8
Q
Identify the 3 structures in the respiratory zone of the respiratory system
A
- Respiratory bronchiole
- Alveolar duct
- Alveolus
9
Q
Identify 2 functions of the cartilage in the trachea
A
- Keeps airway open (patency)
- Enables movement during breathing
10
Q
Why is the tracheal cartilage C-shaped?
A
The cartilage opens at the esophagus and is replaced by connective tissue and muscle allowing the bolus to press against the trachea and be swallowed easily
11
Q
Which parts of the body do the superior and inferior thoracic aperture communicate with respectively?
A
- Superior thoracic aperture communicates with the neck
- Inferior thoracic aperture communicates with the abdomen
12
Q
Which specific nerves innervate the diaphragm?
A
Left and right phrenic nerves
C3, C4, C5 keep the diaphragm alive
13
Q
Which segment of the nervous system innervates the diaphragm?
A
The diaphragm is a somatically innervated skeletal muscle (voluntary control)
14
Q
How do we ventilate the lungs?
A
- Increase the volume of the thoracic cavity
- Reducing the alveolar pressure
15
Q
What are the three layers of intercostal muscles connecting the ribs together?
A
- External intercostal muscle
- Internal intercostal muscle
- Innermost intercostal muscle
16
Q
What is the primary function of the external intercostals?
A
Assist inhalation
17
Q
Internal intercostals are antagonists to external intercostals.
Thus, state their function
A
Assists exhalation (especially forced exhalation)
18
Q
What is the location of the main neurovascular bundle for the intercostals?
A
Below the rib, hence entry during pleural aspiration or insertion of chest drain is always made above the rib
19
Q
Which three structures pass through the diaphragm?
A
- Vena Cava
- Oesophagus
- Aorta
20
Q
At what vertebral levels do the three structures pass through the diaphragm?
A
- Vena cava (T8)
- Aortic hiatus (T12)
- Oesophagus (T10)
Levels correspond to the number of letters in each structure
21
Q
What are the components of the intercostal neurovascular bundle?
A
- Intercostal nerve
- Intercostal vein
- Intercostal artery
22
Q
What is the azygos vein and what does it do?
A
The azygos vein is a vein running up the side of the thoracic vertebral column draining itself towards the superior vena cava.
23
Q
What are the articulating points of the rib cage?
A
- The ribs articulate with the vertebral column posteriorly
- The ribs terminate anteriorly as cartilage (costal cartilage)
24
Q
The typical rib consists of three components.
Identify them
A
- Head
- Neck
- Body
25
Describe the shape of the head of a typical rib
The **head** is wedge shaped and has two articular facets separated by a wedge of bone
* forms the costovertberal joints
26
Identify the different articulation points of the head of the rib
- One facet articulates with the **numerically corresponding vertebrae**
- The other articulates with the **vertebrae above**
27
Describe the articulation points of the neck of a typical rib
Where the neck meets the body there is a roughed tubercle which articulates with the **transverse process of corresponding vertebrae**
28
Describe the structure and function of the body/shaft of the rib
- **Structure**: flat and curved
- **Function**: internal surface of the shaft has a groove for the neurovascular supply of the thorax, protecting them from damage
29
What are the four characteristic features of the thoracic vertebrae?
- Vertebral body is **heart shaped**
- **Demi-facets** on each side of vertebral body
- **Costal-facets** on transverse process
- Spinous processes are **long** and **slanted inferiorly**
30
Explain why hoarseness of the voice may be a sign of intrathoracic disease
- Hoarseness is a **symptom** not a disease
- It is related to **swelling**, **inflammation** and an upper respiratory tract **infection**
31
Describe the rib movements during inhalation and exhalation
- **Inhalation**
I. Chest cavity enlarges
II. Rib cage moves upward and outward
- **Exhalation**
I. Chest cavity reduces
II. Rib cage moves downward and inward
32
Describe the anatomical position of the lungs
- The lungs lie on either side of the **mediastinum**, within the thoracic cavity
- Each lung is surrounded by a **pleural cavity**
33
Which 4 structures does the mediastinal surface of the left lung lie in close proximity to?
- Heart
- Arch of aorta
- Thoracic aorta
- Oesophagus
34
Which 5 structures does the mediastinal surface of the right lung lie in close proximity to?
- Oesophagus
- Heart
- Inferior vena cava
- Superior vena cava
- Azygos vein
35
Briefly describe the structure of the lungs
Each lung consists of:
- An apex
- Base
- Lobes
- Three surfaces
- Three borders
36
What are the three surfaces of the lungs?
- Costal (faces internal surface of chest wall, smooth)
- Mediastinal (lateral aspect of middle mediastinum)
- Diaphragmatic (concave)
37
Which lung is smaller?
The **left lung** is slightly smaller than the right due to the **presence of the heart**
* adjacent to the heart, aortic arch, descending aorta, oesophagus, left phrenic nerve, vagus nerve and left recurrent layrngeal nerve
38
Distinguish the lobular structure of the left and right lungs
- The **right lung** has three lobes (superior, middle and inferior) separated by oblique and horizontal fissures
- The **left lung** has two lobes (superior and inferior) separated by a similar oblique fissure
39
What is the lung root?
The **lung root** is a collection of structures that suspends the lung from the mediastinum
40
Identify the contents of each lung root
- Bronchus
- Pulmonary artery
- 2 pulmonary veins
- Lymphatic vessels
- Pulmonary plexus of nerves
41
All the structures in the lung root enter/leave via the hilum.
What is this?
The **hilum** is a wedge shaped area on the mediastinal surface of the lung
42
Briefly describe the arterial supply and venous drainage of the lungs
- The lungs are supplied with deoxygenated blood by the **paired pulmonary arteries**
- Once the blood receives oxygenation, it leaves the lungs via the **four pulmonary veins** only a small amount of blood leaves via the **bronchial veins**
43
Describe the venous drainage and arterial supply of the bronchi, lung roots and visceral pleura
- Arterial supply via the **bronchial arteries** which arise from the **descending aorta**
- Venous drainage via the **bronchial veins:**
I. Right - drains into **azygos vein**
II. Left - drains into **accessory hemiazygos vein**
44
The nerves of the lungs are derived from pulmonary plexuses.
Describe the parasympathetic and sympathetic supply of the lungs
- **Parasympathetic**: derived from the vagus nerve
- **Sympathetic**: derived from the sympathetic trunks
sympathetic efferent fibres are bronchodilators and vasoconstrictor
45
There are two pleurae in the body, consisting of a serous membrane.
How can the pleura be divided into two parts?
- **Visceral pleura** which covers the lungs
- **Parietal pleura** which covers the internal surface of the thoracic cavity, extends into the costo-diaphragmatic recess
46
The parietal pleura is the thicker pleura and can be subdivided into 4 parts.
Identify and describe these
- **Mediastinal pleura** lines lateral aspect of mediastinum
- **Cervical pleura** lines neck extension of pleural cavity
**- Costal pleura** covers inner aspect of ribs, etc
- **Diaphragmatic pleura** covers surface of diaphragm
47
Describe the structure of the visceral pleura
- Covers **outer surface** of lungs
- Extends into **interlobar fissures**
- **Continuous with the parietal pleura** at hilum of each lung
48
What is the pleural cavity?
The **pleural cavity** is a potential space between the parietal and visceral pleura which contains a small volume of serous fluid
49
What are the two functions of the parietal pleura?
- **Lubricates the pleural surfaces**, allowing friction-free movement
- **Produces surface tension**, pulling the pleurae together and ensuring the lungs expand during inspiration
50
What are recesses?
- The pleural cavity is not completely filled by the lungs anteriorly and posteroinferiorly.
- It gives rise to **recesses**, which are potential spaces where opposing surfaces of the parietal pleura touch
51
There are two recesses in each pleural cavity.
Identify and describe their location
- **Costodiaphragmatic**: located between the costal pleurae and the diaphragmatic pleura
- **Costomediastinal**: located between the costal pleurae and the mediastinal pleurae, behind the sternum
52
What happens when fluid collects in the pleural recesses?
53
Compare and contrast the vascular supply of the parietal and visceral pleura
- **Parietal**: intercostal arteries
- **Visceral**: internal thoracic arteries
54
Compare and contrast the innervation of the visceral and parietal pleura
- **Visceral**: pulmonary plexus – sensitive to distension only
- **Parietal**: phrenic and intercostal nerves – sensitive to pressure, pain and temperature
55
What is pneumothorax?
- **Pneumothorax** is a condition which occurs when air or gas is present within the pleural space
- This removes surface tension of the serous fluid in the space and reduces lung extension
56
What is the sternal angle?
The **sternal angle** is a joint formed by the articulation of the manubrium and the body of the sternum, a transverse ridge
57
How can one find the sternal angle?
- Find the sternal notch
- Walk your fingers down the manubrium a few centimetres
- Feel for a distinct bony ridge
58
The costal cartilages of which rib articulate with the sternum at the level of the sternal angle?
The second rib
59
difference between the structure of a bronchus and bronchiole
* bronchus has very little cartilage so can easily collapse and so needs support of the alveoli to maintain the shape
60
how does the bronchus keep open
* radial traction
* alveoli form an outward pressure away from the bronchus and creates tension
61
what is the upper respiratory tract made up of? and how is it conductive to warming, humidifying and filtering air particles?
– nose
– pharynx and larynx (paranasal sinuses)
* warming → air heated on passage through nose, water vapour added
* humidified → transudation of fluid via epithelium
* filtering → via cilia trapping large particles in air
62
what is the role of the larynx?
* connects the pharynx to the trachea
* contains the vocal chords which are the entrance to the trachea
63
which muscles and nerves innervate the vocal chords?
* intrinsic laryngeal muscles
* the recurrent laryngeal nerves (has a long course on the left side so is susceptible to compression during intra thoracic disease =\> hoarse voice)
64
explain how the cough reflex works
* closing of vocal chords build up the intra thoracic pressure
* this is followed by the sudden opening of the vocal chord
* air is expelled out
65
describe the reason for airway obstruction
* opening between vocal chords can present as airway obstruction → difficult to breathe
66
what is the sternum made of?
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67
how do the internal intercostal muscles aid chest expansion? what direction are their fibres
* fibres run **down and posteriorly**
* pull **ribs down**
* active only during **FORCED** expiration
* work closely with the **innermost intercostal muscles**
68
how do external intercostal muscles aid chest expansion? what direction are the fibres
* fibres run down **anteriorly and down** from inferior to superior margins of rib
* contribute to **30% chest expansion**
* **elevates the ribs**
69
how much chest expansion is the diagram responsible for
70%
70
where does the trachea start and end
* starts at the lower border of the cricoid cartilage
* terminates at level of sternal angle
71
what is the angle between the left and right bronchi called
carina
72
what is the angle between the left and right bronchi called
carina
73
why are foreign bodies most likely to get trapped in the right main bronchus?
* right main bronchus is shorter and more vertical than the left
* found in middle lobe
74
how many bronchi divide on the left and how many divide on the right
* 3 lobar bronchi on the right for the superior, middle and inferior lobe
* 2 lobar bronchi on the left for the superior and inferior lobe
75
what is a segmental bronchi
* division of the lobar bronchi
76
what is a bronchopulmonary segment and what is its clinical relevance
→ area of lung supplied by segmental bronchus
→ pulmonary artery
→ drained by segmental vein
→pyramid shaped
→ Clinical relevance: bronchoscopy, so you can isolate separate segment
77
Which divisions of the bronchioles are known as the conducting zones
1-16
78
which parts of the lungs make up the respiratory zone?
* respiratory bronchioles → have occasional alveoli
* alveolar ducts → lined with alveoli
* alveolar sac → composite airspace with numerous alveoli open
79
what is the right lung adjacent to?
superior vena cava, azygous vein, right atrium, oesophagus, right phrenic nerve, vagus nerve and sympathetic trunk
80
what can damage to the phrenic nerve cause?
* it can paralyse the diaphragm and cause breathlessness
81
what can damage to the left recurred pharyngeal nerve cause?
* paralysis intrinsic laryngeal muscle
* vocal cord paralysis
* voice becomes hoarse
82
briefly describe the lymphatic drainage of the lungs
* hilar nodes (bronchopulmonary nodes)
* these nodes can turn into tracheobronchial nodes which can widen the angle of the carina
83
which fissure seperates the left lung lobes?
* oblique → separates upper and lower and extends from T2\
84
Which fissure in the right lung separates the right upper and middle lobes
* horizontal fissure
85
what is the extent of the pleural cavity?
* the pleural cavity lies lower 2 ribs lower than the lung
86
what type of blood does pulmonary arteries carry
deoxygenated
87
what is the structural comparison between a bronchus and a bronchiole?
* bronchus has areas of cartilage around it
* bronchiole has no cartilage
* bronchus has small glands in the submucosa
* bronchiole has no glands
