RA16 Thorax Breast Lungs Anatomy

Question 1

Upper respiratory tract

Anatomy

Answer 1

Nose to larynx:
- Nasal cavity
- Pharynx
- Larynx

Question 2

Lower respiratory tract

Anatomy

Answer 2

Trachea to lungs/alveoli:
- Trachea
- Bronchi
- Lungs

Contains conducting and respiratory zones

Question 3

Conducting zone
- Structures
- Function

Anatomy

Answer 3

Structures:
- Trachea
- Bronchi
- Bronchioles
- Terminal bronchioles

Function:
- Air conduction (get air to alveoli)
- Air condition (warm the air)
- Air filtration (remove/trap particles)

Question 4

Respiratory zone
- Structures
- Function

Anatomy

Answer 4

Structures:
- Respiratory bronchioles
- Alveolar sacs

Function:
- Gas exchange

Question 5

Layers of trachea and bronchi

Histology

Answer 5

From luminal surface downwards:
- Mucosa: ciliated pseudostratified columnar epithelium -> lamina propria (cellular CT)
- Submucosa: denser CT, contains seromucous glands
- Hyaline cartilage
- Adventitia: dense irregular CT

Question 6

Trachea:
- Epithelium? Ciliated?
- Secretory cell?
- Cartilage?
- Smooth muscle?
- Glands?

Histology

Answer 6

• Pseudostratified columnar ciliated
• Goblet cells
• C-shaped cartilage
• Trachealis smooth muscle connecting the ends of the C-shaped cartilage
• Serous + mucous glands

Question 7

Bronchi:
- Epithelium? Ciliated?
- Secretory cell?
- Cartilage?
- Smooth muscle?
- Glands?
- Others?

Histology

Answer 7

• Pseudostratified columnar ciliated
• Goblet cells
• Pieces of cartilage
• Smooth muscle encircles lumen; between cartilage and epithelium
• Serous + mucous glands
• Surrounded by lung tissue (vs trachea: not surrouded by lung tissue)

Question 8

Bronchioles (first to terminal):
- Epithelium? Ciliated?
- Secretory cell?
- Cartilage?
- Smooth muscle?
- Glands?

Histology

Answer 8

• Simple columnar ciliated
• Goblet cells; club cells in terminal bronchioles
• No cartilage
• Thick circular smooth muscle
• No glands

Question 9

Respiratory bronchioles:
- Epithelium? Ciliated?
- Secretory cell?
- Cartilage?
- Smooth muscle?
- Glands?
- Others?

Histology

Answer 9

• Simple cuboidal, some cilia
• Club cells
• No cartilage
• Knobs of smooth muscle
• No glands
• Alveoli in walls (vs bronchioles: no alveoli in walls)

Question 10

Alveolar ducts:
- Epithelium? Ciliated?
- Secretory cell?
- Cartilage?
- Smooth muscle?
- Glands?

Histology

Answer 10

• Simple squamous, no cilia
• No secretory cells
• No cartilage
• Smooth muscle may or may not be present
• No glands

Question 11

Alveoli
- Epithelium? Ciliated?
- Secretory cell?
- Cartilage?
- Smooth muscle?
- Glands in connective tissue?

Histology

Answer 11

• Simple squamous, no cilia (type 1 and 2 pneumocytes)
• Type 2 pneumocytes
• No cartilage
• No smooth muscle
• No glands

Question 12

Type 1 vs type 2 pneumocytes (in alveoli)
- Structure
- Function
- % of total alveolar area
- % of total number of cells

Histology

Answer 12

Type 1:
- Structure: simple squamous cells, close to capillaries
- Function: gas exchange
- 95% of total alveolar area
- Least number of cells

Type 2:
- Structure: bulges out into alveolar air space
- Function: secrete surfactant -> reduces surface tension -> prevents alveolar collapse
- 5% of total alveolar area
- 60% of total number of cells

Question 13

What are lamella bodies?

Answer 13

• Secretory organelles in type II pneumocytes in alveoli
• Stores phosphotidylcholine, a component of surfactant

Question 14

Club cells
- Location
- Structure
- Function

Answer 14

• Location: terminal and respiratory bronchioles
• Structure: cuboidal, non-ciliated
• Function: secrete surfactant components, degradation of toxins, regenerate into bronchiolar epithelium (stem cell properties)

Question 15

Function of alveolar macrophages

Answer 15

• Phagocytose foreign materials
• Initiate immune response by releasing cytokines

Question 16

Epithelium of false vocal cord (vestibular fold)

Answer 16

Ciliated pseudostratified columnar

Question 17

Epithelium of true vocal cord (vocal fold)

Answer 17

Stratified squamous

Question 18

What is the space between the true and false vocal cords?

Answer 18

Ventricle

Question 19

Stages of lung development (5)

Embryology: lung development

Answer 19

1. Embryonic (4-9 weeks): trachea and bronchi develop
   -> Error leads to tracheoesophageal fistula/esophageal atresia
2. Pseudoglandular (5-18 weeks): bronchioles and terminal bronchioles develop
   -> Fetus unable to survive if born
3. Canalicular (16-26 weeks): respiratory bronchioles develop
   -> Limited respiration possible starting around week 24
   -> Surfactant production begins aroud week 22, but insufficient to prevent airway collapse (atelactasis)
4. Saccular (26 weeks - birth): alveolar ducts develop
   -> Surfactant production is sufficient to prevent atelactasis around week 36
   -> Premature babies can survive
5. Alveolar (36 weeks - 8 years): alveolar sacs develop

EPCSA: Every Pulmonologist Can See Alveoli

Question 20

Error in embryonic stage of lung development leads to what disorder?
- Prenatal and postnatal complications?

Embryology: lung development

Answer 20

Tracheoesophageal fistula and/or esophageal atresia - due to incomplete separation of trachea and esophagus (typically around 4th-8th weeks)

Prenatal complications:
- Polyhydramnios - excess amniotic fluid due to inability to swallow

Postnatal complications:
- Regurgitation - immediate coughing and choking upon feeding
- Pneumonitis (inflammation) / pneumonia (infection) - gastric contents reflux intro trachea and lungs

Question 21

What defects are tracheoesphageal fistula associated with?

Embryology: lung development

Answer 21

VACTERL:
- Vertebral anomalies
- Anal atresia
- Cardiac defects
- Tracheoesophgeal fistula
- Esophageal atresia
- Renal atresia
- Limb defects

Question 22

When does surfactant production begin?

Embryology: lung development

Answer 22

Week 22

Question 23

Respiratory distress syndrome
- Cause?

Embryology: lung development

Answer 23

• Surfactant production begins around week 22
• Affects premature babies with surfactant deficiency -> increased surface tension of alveoli -> alveolar collapse

Question 24

What develops into the following parts of the diaphragm?
- Central tendon
- Membranous part
- Muscular part
- Crura

Embryology: diaphragm development

Answer 24

• Septum transversum -> central tendon
• Pleuroperitoneal membrane -> membranous part
• Somites C35 -> muscular part
• Mesentary of esophagus -> crura

Question 25

Which somites do the muscles of the diaphragm arise from? ## Footnote Embryology: diaphragm development

Answer 25

C3-5 | C3, 4, 5 keep the diaphragm alive

Question 26

How does the diaphragm develop? ## Footnote Embryology: diaphragm development

Answer 26

- **Septum transversum** grows from anterior to posterior, stopping at the gut tube - Leaves 2 **pleuropertioneal canals** at the left and right sides - Pleuropertioneal canals are closed off by the growth of **pleuroperitoneal membranes** (arise from posterior body wall)

Question 27

What do defects in the development of pleuroperitoneal membranes lead to? ## Footnote Embryology: diaphragm development

Answer 27

**Congenital diaphragmatic hernia** - Pleuroperitoneal canals fail to close off -> hole in diaphragm - Abdominal contents herniate into pleural cavities - Associated with pulmonary hypoplasia (can't develop lungs)

Question 28

What are the main components of the thoracic skeleton? ## Footnote Anatomy

Answer 28

- 12 pairs of **ribs** and c**ostal cartilages** - 12 **thoracic vertebrae** and **intervertebral discs** - **Sternum**

Question 29

What are the 3 classes of ribs? ## Footnote Anatomy

Answer 29

True (vertebrosternal) ribs - Ribs 1-7 - Attached directly to sternum anteriorly False (vertebrochondral) ribs - Ribs 8-10 - Attached indirectly to sternum at the costal margin via fused costal cartilages Floating (free) ribs - Ribs 11 and 12 (sometimes 10) - Not attached to sternum

Question 30

Which ribs are the typical and atypical ribs? ## Footnote Anatomy

Answer 30

Typical ribs: 3-9 Atypical ribs: 1-2, 10-12

Question 31

What are the parts of a typical rib? (4) ## Footnote Anatomy

Answer 31

- **Head**: *inferior facet* articulates with numerically coresponding vertebra; *superior facet* articulates with superior vertebra - **Neck**: connects head and body of rib - **Tubercle**: articulates with transverse process of corresponding vertebra - **Body**: internal surface contains the *costal groove*, which contains the intercostal veins, arteries, and nerves

Question 32

What does the costal groove (in intercostal space) contain, from superior to inferior? ## Footnote Anatomy: neurovasculature of intercostal space

Answer 32

VAN: - Intercostal **vein** - Intercostal **artery** - Intercostal **nerve**

Question 33

The neurovasculature of the intercostal space is located between which muscles? ## Footnote Anatomy: neurovasculature of intercostal space

Answer 33

Between the internal and innermost intercostal muscles

Question 34

Veins in intercostal space ## Footnote Anatomy: neurovasculature of intercostal space

Answer 34

- Posterior and anterior **intercostal** veins - **Subcostal** vein

Question 35

Pathway of posterior intercostal veins ## Footnote Anatomy: neurovasculature of intercostal space

Answer 35

Posterior intercostal veins -> azygos vein -> superior vena cava

Question 36

Arteries in intercostal space and their origin ## Footnote Anatomy: neurovasculature of intercostal space

Answer 36

- Posterior and anterior **intercostal** arteries - **Collateral** branches Mostly derived from **thoracic aorta**

Question 37

Nerves in intercostal space and their origin ## Footnote Anatomy: neurovasculature of intercostal space

Answer 37

- **Intercostal** nerves: anterior rami of **T1-T11** - **Subcostal** nerves: anterior rami of **T12** (supplies subcostal space below T12)

Question 38

Where should one insert the needle during thoracentesis (inserting a needle through the intercostal space to remove fluid/air from the lungs)?

Answer 38

Superior to the rib (but not right above) in order to avoid damaging the collaterals

Question 39

Muscles for quiet and forced inspiration ## Footnote Anatomy: muscles for respiration

Answer 39

Quiet inspiration: - **Diaphragm** - **External** intercostal muscles Forced inspiration: - Accessory muscles: **scalene**, **sternocleidomastoid**, pectoralis major and minor, serratus anterior, latissimus dorsi, trapezius

Question 40

Muscles for quiet expiration and forced expiration ## Footnote Anatomy: muscles for respiration

Answer 40

Quiet expiration: - Main driver is **elastic recoil** of lungs Forced expiration: - **Internal** intercostal muscles - **Innermost** intercostal muscles - **Subcostal** muscles - **Transversus thoracis** - **Anterior abdominal wall** muscles

Question 41

Inspiratory muscles (...) the ribs while expiratory muscles (...) the ribs ## Footnote Anatomy: muscles for respiration

Answer 41

**Inspiratory** muscles **elevate** the ribs while **expiratory** muscles **depress** the ribs

Question 42

How does the thoracic wall move during inspiration? - Muscles and diaphragm? - Diaphragm moves? - Vertical dimension? - AP dimension? - Transverse dimension? - Intrathoracic diameter? - Intrathoracic volume? - Intrathoracic pressure? - Air flow direction? - Intra-abdominal pressure? - Abdominal viscera? ## Footnote Anatomy: movement of thoracic wall

Answer 42

- Muscles and diaphragm: **contract** - Diaphragm moves: **down** - Vertical dimension: **increase** - Anteroposterior dimension: **increase** - Transverse dimension: **increase** (during forced inspiration) - Intrathoracic diameter: **increase** - Intrathoracic volume: **increase** - Intrathoracic pressure: **decrease** - Air flow direction: **into lungs** - Intra-abdominal pressure: **increase** - Abdominal viscera: **compress**

Question 43

How does the thoracic wall move during expiration? - Muscles and diaphragm? - Diaphragm moves? - Vertical dimension? - AP dimension? - Transverse dimension? - Intrathoracic diameter? - Intrathoracic volume? - Intrathoracic pressure? - Air flow direction? - Intra-abdominal pressure? - Abdominal viscera? ## Footnote Anatomy: movement of thoracic wall

Answer 43

- Muscles and diaphragm: **relax** - Diaphragm moves: **up** - Vertical dimension: **decrease** - Anteroposterior dimension: **decrease** - Transverse dimension: **decrease** (during forced expiration) - Intrathoracic diameter: **decrease** - Intrathoracic volume: **decrease** - Intrathoracic pressure: **increase** - Air flow direction: **out of lungs** (due to increase in intrathoracic pressure and elastic recoil of lungs) - Intra-abdominal pressure: **decrease** - Abdominal viscera: **decompress**

Question 44

What nerve innervates the diaphragm? Which spinal root(s) does it originate from?

Answer 44

Phrenic nerve (C3-C5)

Question 45

What structures perforate the diaphragm? - Aperture - Location in diaphragm - Vertebral level - Structures passing through

Answer 45

**T8:** - Caval opening - Central tendon - **Inferior vena cava**, right phrenic nerve **T10:** - Esophageal hiatus - Right crus - **Esophagus**, vagus nerve **T12:** - Aortic hiatus - Between left and right crura - **Aorta**, azygos vein, thoracic duct | I 8 (ate) 10 eggs at 12

Question 46

What are the 3 routes of metastasis in breast cancer? ## Footnote Anatomy

Answer 46

1. To **lungs**: via lympathic channels (axillary lymph nodes) -> liver, CNS endocrine system, appendicular skeleton 2. To **liver**: via abdominal lympathic system 3. To **vertebrae**: via intercostal veins -> azygos/hemiazygos veins -> vertebral venous plexus of Batson

Question 47

Transverse thoracic plane - What does it separate? - Between which vertebrae? - Marked by what structure?

Answer 47

- Separates **superior** and **inferior medistinum** - Located between **T4** and **T5** - Marked by **sternal angle** (at manubriosternal joint)

Question 48

Structures in transverse thoracic plane

Answer 48

- T4 and T5 IV disc - Start and end of aortic arch - Bifurcation of trachea (carina) - Bifurcation of pulmonary trunk - Ascending thoracic duct

Question 49

Parietal pleura - Location - Sections (4) - Arteries - Innervation (nervous system + nerves) - Sensitive to?

Answer 49

- Covers internal surface of **thoracic cavity** - **Cervical** (superior), **costal** (inner surface of thoracic wall), **mediastinal** (lateral surface of mediastinum), **diaphragmatic** (superior surface of diaphragm) pleura - **Intercostal** arteries - **Somatic** nervous system: **intercostal** nerves (lateral wall) + **phrenic** nerve (diaphragmatic surface) - Sensitive to **pain**, **temperature**, **touch**

Question 50

Visceral pleura - Location - Arteries - Innervation (nervous system) - Sensitive to?

Answer 50

- Covers the **lungs** - **Bronchial** arteries - **Autonomic** nervous system - Sensitive to **stretch** only

Question 51

What is the space between the parietal and visceral pleura?

Answer 51

Pleural cavity

Question 52

The parietal and visceral pleura are continous at the (...)

Answer 52

The parietal and visceral pleura are continous at the **hilum** (site of entry of root of lung)

Question 53

Pleural reflections

Answer 53

The lines along which the parietal pleura changes direction as it passes from one wall of the pleural cavity to another

Question 54

What are the 3 types of plerual reflection? - View - Line - Inferior margin of lung vs parietal pleura

Answer 54

Sternal reflection: - Anterior view - Midclavicular line - 6th vs 8th rib Costal reflection: - Lateral view - Midaxillary line - 8th vs 10th rib Vertebral reflection: - Posterior view - Scapular line - 10th vs 12th rib

Question 55

The pleura descends below the costal margin at the (...) and (...)

Answer 55

The pleura descends below the costal margin at the **costovertebral angles** and **right infrasternal angles**

Question 56

Pleural recess

Answer 56

Spaces where the pleural cavity is not completely filled by the lungs - Formed by opposing parietal pleura - Filled with pleural fluid

Question 57

What are the 2 types of pleural recesses?

Answer 57

1. **Costodiaphragmatic** recess: between costal and diaphragmatic pleura 2. **Costomediastinal** recess: between costal and mediastinal pleura, behind the sternum

Question 58

What do pleural injuries lead to?

Answer 58

**Pneumothorax**: air from lungs leaks into the plerual cavity (the space between visceral and parietal pleura)

Question 59

Possible sites of pleural injury (3) - What injuries are they susceptible to?

Answer 59

1. **Cervical pleura**: suscpetible to injuries at base of neck 2. **Right infrasternal angle**: susceptible to abdominal incision injury 3. **Left and right costovertebral angles**: susceptible to abdominal incision injury

Question 60

Relationship of pulmonary artery and bronchi

Answer 60

- **Right** lung: pulmonary artery **anterior** to bronchi - **Left** lung: pulmonary artery **superior** to bronchi | RALS: Right Anterior Left Superior

Question 61

How many lobes does the right lung have? What are they?

Answer 61

Right lung has 3 lobes: 1. Upper lobe 2. Middle lobe 3. Lower lobe

Question 62

How many lobes does the left lung have? What are they?

Answer 62

Left lung has 2 lobes: 1. Upper lobe 2. Middle lobe

Question 63

What fissures separate the lobes of the right lung?

Answer 63

- **Major** fissure: separates right **upper and middle** lobe from right **lower** lobe - **Minor** fissure: separates right **upper** lobe from right **middle** lobe

Question 64

What fissure separate the lobes of the left lung?

Answer 64

**Major** fissure: separates the left upper and lower lobes

Question 65

Pulmonary circulation of lungs - Function - Pathway - Oxygen content of blood - Pressure vs flow

Answer 65

- Carries deoxygenated blood from heart to lungs for oxygenation - Right ventricle -> pulmonary trunk -> pulmonary arteries -> lungs -> pulmonary veins -> left atrium - Dexoygenated blood - Low pressure, high flow

Question 66

Bronchial circulation of lungs - Function - Pathway - Oxygen content of blood - Pressure vs flow

Answer 66

- Supplies oxygenated blood to larger airways, hilum, and supporting tissue of lungs - Thoracic aorta -> bronchial arteries -> lung tissue -> bronchial vein 1. Bronchial vein -> azygos/hemiazygos vein -> superior vena cava -> right atrium 2. Bronchial vein -> pulmonary vein -> left atrium - Oxygenated blood - High pressure, low flow

Question 67

Branching of bronchi

Answer 67

Trachea -> 2 **main/primary** bronchi (one to each lung) -> **lobar/secondary** bronchi (2 on left, 3 on right; each supplies a lobe of the lung) -> **segmental/tertiary** bronchi (supply bronchopulmonary segments) [-> bronchioles -> terminal bronchioles -> respiratory bronchioles -> alveolar ducts -> alveolar sacs -> alveoli]

Question 68

Structure of right vs left main bronchus

Answer 68

The right main bronchus is **wider**, **shorter**, and runs **more vertically** then the left main bronchus

Question 69

Bronchopulmonary segment - Shape - Location of apex vs base

Answer 69

- Pyramidal shape - Apex faces root of lung - Base at pleural surface

Question 70

Which of the following structures lie anterior to the right superior pulmonary vein? A. Right sympathetic thoracic trunk B. Right vagus nerve C. Right phrenic nerve D. Right pulmonary artery E. Right main bronchus ## Footnote RA16 Q13

Answer 70

C. Right phrenic nerve | See Moore’s essential clinical anatomy pg 209 Fig 4.18

Question 71

A 20-year-old man is being seen in the A&E for facial swelling. A CT scan of the chest demonstrates a large thymic mass. Compression of which of the following structures by the thymic mass would account for his symptoms? A. Superior vena cava B. Azygos vein C. Right superior pulmonary vein D. Right pulmonary artery E. Ascending aorta ## Footnote RA16 Q14

Answer 71

A. Superior vena cava

Question 73

A swallowed coin would most likely become lodged in which lobe of the lungs? ## Footnote RA16 Q16

Answer 73

Right lower lobe - The right bronchus is wider, shorter and more vertical than left bronchus -> stuff more likely to enter right bronchus - Gravity will pull the coin to the lower lobe

Question 74

A child diagnosed with primary ciliary dyskinesia presents with upper and lower respiratory tract infections. What is the likley pathological reason? A. Production of thick mucin that cannot be cleared B. Impairment of the mucociliary escalator C. Presence of club cells in the alveoli D. Overproduction of pulmonary surfactant E. Tracheal aplasia ## Footnote RA16 Q17

Answer 74

B. Impairment of the mucociliary escalator - Primary ciliary dyskinesia: cilia cannot move well or at all -> cannot propel mucus and germs out of lungs A: Cystic fibrosis - causes thick and viscous mucus, which is a breeding ground for germs and is harder to transport out of lungs C: Not pathological E: Absence of trachea -> incompatible with life