Lung Radiology and Histology Flashcards
1
Q
Extrapleural fascia
A
Loose, thin layer of connective tissue that separates the parietal pleura from its overlying structures
2
Q
Pulmonary ligament
A
Uncovered by pleura. Forms a ‘ dead - space ’ for distension of the pulmonary veins.
3
Q
Since the parietal pleura is segmentally innervated by the intercostal nerves, infl ammation of the pleura results in. . .
A
. . . pain referred to the cutaneous distribution of these nerves (i.e. to the thoracic wall or, in the case of the lower nerves, to the anterior abdominal wall, which may mimic an acute abdominal emergency)
4
Q
The trachea
A
Commences just below the circoid cartilage and continues until the bifurcation at the sternal angle.
5
Q
What surrounds the cervical trachea on each side?
A
Anteriorly – the isthmus of the thyroid gland, inferior thyroid veins, sternohyoid and sternothyroid muscles.
Laterally – the lobes of the thyroid gland and the common carotid artery.
Posteriorly – the esophagus with the recurrent laryngeal nerve lying in the groove between the oesophagus and trachea
6
Q
What surrounds the thoracic trachea on each side?
A
Anteriorly – commencement of the brachiocephalic artery and left carotid artery, both arising from the arch of the aorta, the left brachiocephalic vein and the thymus
Posteriorly – esophagus and left recurrent laryngeal nerve
To the left – arch of the aorta, left common carotid and left subclavian arteries, left recurrent laryngeal nerve and pleura
To the right – vagus, azygos vein and pleura
7
Q
The interior of the trachea is lined with. . .
A
. . . ciliated respiratory epithelial cells and goblet cells.
8
Q
Axial radiograph of the thoracic trachea
A
9
Q
The golden rule of tracheostomy
A
Stick to the midline
There are many important structures flanking the trachea.
10
Q
Widening and distortion of the angle between the bronchi (the carina)
A
a serious prognostic sign, since it usually indicates carcinomatous involvement of the tracheobronchial lymph nodes around the bifurcation of the trachea.
11
Q
Dual blood supply of the lungs
A
Descending aorta -> bronchial arteries -> azygos vein
Pulmonary trunk -> pulmonary arteries -> superior and inferior pulmonary veins
12
Q
Lymphatics of the lungs
A
The lymphatics of the lung drain centripetally from the pleura towards the hilum. The bronchopulmonary lymph nodes are at the hilum, and the more efferent tracheobronchial nodes are at the tracheal bifurcation, and the more efferent still paratracheal nodes along the trachea leading to the thoracic duct or right duct.
13
Q
Innervation of the lungs
A
The pulmonary plexuses derive fibres from both the vagi and the sympathetic trunk.
They supply efferents to the bronchial musculature (sympathetic bronchodilator fibres) and receive afferents from the mucous membrane of the bronchioles and from the alveoli.
14
Q
Lung lobe subdivisions
A
Each lobe of the lung is subdivided into a number of bronchopulmonary segments, each of which is supplied by a segmental bronchus, artery and vein. These segments are wedge - shaped with their apices at the hilum and bases at the lung surface
15
Q
Named divisions of main bronchi
A
16
Q
Transverse and oblique sinuses
A
17
Q
Anterior heart view
A
18
Q
Posterior heart view
A
19
Q
Rupture of a papillary muscle
A
Allows prolapse of the affected cusp to occur into the atrium at each systole, with consequent acute cardiac failure
20
Q
chordae tendineae
A
Connect the papillae to the valves
21
Q
Location of the sinoatrial node
A
Situated in the upper part of the crista terminalis just to the right of the opening of the superior vena cava into the right atrium
22
Q
Location of the atrioventricular node
A
Situated in the atrial septum immediately above the opening of the coronary sinus
23
Q
Location of the Bundle of His
A
Runs from the AV node and divides at the junction of the membranous and muscular parts of the interventricular septum into its right and left branches, which run immediately beneath the endocardium to activate all parts of the ventricular musculature.
24
Q
When the ventricle contracts in systole, the papillary muscles. . .
A
. . . shorten, the chordae tendineae are pulled upon and the tricuspid valve is prevented from prolapsing into the right atrium.
25
Coronary veins
26
The coronary sinus receives. . .
1. the **great cardiac vein** in the anterior interventricular groove
2. the **middle cardiac vein** in the inferior interventricular groove
3. the **small cardiac vein** – accompanying the marginal artery along the lower border of the heart
4. the **oblique vein** – descends obliquely on the posterior aspect of the left atrium
27
Innervation of the heart
The nerve supply of the heart is derived from the **vagus (parasympathetic cardio - inhibitor)** and the **cervical and upper fi ve thoracic sympathetic ganglia (cardio - accelerator)** by way of superficial and deep cardiac plexuses.
28
Development of the heart
29
Developmental heart chambers
30
Fetal circulation
31
Dextrorotation of the heart
this organ and its emerging vessels lie as a mirror - image to the normal anatomy
32
Closing of the foramen ovale
At birth, the septum primum and septum secundum are forced together, closing the flap valve of the foramen ovale. Fusion usually takes place approximately 3 months after birth. In approximately 10% of subjects, this fusion may be incomplete. However, **usually**, the two septa overlap and this patency of the foramen ovale is of no functional signifi cance.
33
Atrial septal defects
**Ostium primum defect:** When the septum primum fails to fuse with the endocardial cushions. Lies immediately above the atrioventricular boundary and may be associated with a defect of the pars membranacea septi of the ventricular septum. Both an atrial and ventricular defect.
**Ostium secundum defect:** Occurs if the septum secundum is too short to cover the foramen secundum in the septum primum. **Allows shunting of blood from the left to the right atrium.**
34
Trilocular heart
Result when ventricular septal defects are so pronounced that the ventricles fuse.
35
Congenital pulmonary stenosis
May affect the trunk of the pulmonary artery, its valve or the infundibulum of the right ventricle.
**If stenosis occurs in conjunction with a septal defect**, the compensatory hypertrophy of the right ventricle (developed to force blood through the pulmonary obstruction) develops a suffi ciently high pressure to shunt blood through the defect into the left heart; this **mixing of the deoxygenated right heart blood with the oxygenated left - sided blood** results in the child being **cyanosed at birth**.
36
Fallot’s tetralogy
The most common combination of congenital abnormalities causing congenital cyanosis.
37
Persistent ductus arteriosus
Relatively common congenital anatomical defect. If left uncorrected, it causes progressive work hypertrophy of the left heart and pulmonary hypertension.
38
Dysphagia lusoria
Abnormal development of the primitive aortic arches may result in the aortic arch being on the right or actually being double. An abnormal right subclavian artery may arise from the dorsal aorta and pass behind the oesophagus – a rare cause of difficulty in swallowing
39
Aorta – pulmonary window
Rarely, the division of the truncus into the aorta and pulmonary artery is incomplete. Unusual type of congenital fistula between the two sides of the heart.
40
Layers of the esophagus
1. an outer connective tissue sheath of areolar tissue
2. a muscular layer of external longitudinal and internal circular fibres which are striated in the upper two - thirds and smooth in the lower one - third
3. a submucous layer containing mucous glands
4. a mucosa of stratified epithelium passing abruptly into the columnar epithelium of the stomach
41
esophagus blood supply
Arterial: the **inferior thyroid artery**, branches of the **descending thoracic aorta** and the **left gastric artery**
Venous: The veins from the **cervical part** drain into the **inferior thyroid veins**, from the **thoracic portion** into the **azygos vein** and from the **abdominal portion** partly into the **azygos** and partly into the **left gastric veins**
Note that the left gastric vein drainage is an anastamosis between the portal and caval systems.
42
Aortic coarctation
Thought to be due to an abnormality of the obliterative process which normally occludes the ductus arteriosus.
There may be an **extensive obstruction of the aorta from the left subclavian artery to the ductus**, which is widely patent and maintains the circulation to the lower parts of the body. **Circulation to the lower limb is maintained via collateral arteries** around the scapula anastomosing with the intercostal arteries, and via the link - up between the internal thoracic and inferior epigastric arteries. Often, there are multiple other defects and frequently infants so afflicted die at an early age.
43
Lymphatic drainage of the esophagus
The lymphatic drainage is from a **peri - oesophageal lymph plexus** into the **posterior mediastinal nodes,** which drain both into the **supraclavicular nodes** and into nodes around the left gastric vessels.
It is not uncommon to be able to palpate hard, fixed supraclavicular nodes in patients with advanced oesophageal cancer.
44
Use of esophagus to diagnose mitral stenosis
Use is made of the close relationship between the esophagus and the left atrium in determining the degree of **left atrial enlargement** in mitral stenosis; a **barium swallow may show marked backward displacement of the oesophagus caused by the dilated atrium.**
45
From which side should a surgeon approach the esophagus?
The oesophagus is crossed solely by the **vena azygos** on the **right side**. This is, therefore, the side of election to approach the oesophagus surgically.
46
anterior nares
nostrils
47
pulmonary capillaries
The walls of the alveolar sacs containing an extensive network of specialiezd thin-walled blood vessels
48
squamous metaplasia
Repalcement of respiratory epithelium with squamous epithelium subsequent to prolonged or repeated damage to the respiratory epithelial cells
49
COPD includes. . .
* Asthma
* Chronic bronchitis
* Emphysema
50
Alveolus up close
51
Nasal cavities
nasal cavities NC
nasal septum NS
paranasal sinuses PS
turbinate bones TB
orbital cavities O
anterior cranial fossa ACF
52
Olfactory mucosa
Mucosa of the nasal cavity that contains receptors for the sense of smell. Broadly distributed in most mammals, but in humans it is only a small patch at the very back of the cavity, just caudal to the olfactory bulb of the brain.
53
Waldeyer ring
Ring of lymphoid tissue surrounding the entrance to the pharynx. Protects the respiratory and gastrointestinal systems from anything that comes through the oral passage.
54
Components of the true vocal cord
**Vocalis muscle** and **vocalis ligament** which are responsible for moving the true cord so that it moves towards or away from the true cord on the other side, thus controlling the pitch of the sound made. The true cords are covered by **stratified squamous epithelium SE** which is more resistant to the effects of physical trauma caused by the free margins of the true cords contacting each other during speech.
55
Tracheal submucosa
Lying beneath the lamina propria of the trachea, it is full of mucoserous glands which decrease in number as you go lower down the trachea to the bifurcation.
56
Primary bronchus wall cross section
57
SEM of primary bronchial wall
58
Distal bronchus cross section
59
Respiratory neuroendocrine cell position
60
Bronchiole cross section
61
diffuse neuroendocrine system of the respiratory tract
Diffuse and non-connected neuroendocrine cells secrete serotonin, bombesin, and other chemical mediators which regulate smooth muscle tone in bronchial and vessel walls.
62
Alveoli H and E
63
Type 1 and 2 pneumocytes on histology
64
Type I Pneumocytes
Large squamous cells that cover most of the epithelium of the alveoli. Have an enormous surface area to volume ratio.
65
Type II Pneumocytes
Make up 60% of the actual cells in the lining epithelium, but only take up 5% of the available alveolar surface area. Secrete **surfactant**, which reduces alveolar surface tension, preventing alveolar collapse during expiration. Type II pneumocytes retain the capacity for cell division and can differentiate into type I pneumocytes if required.
**Clara cells** of the respiratory bronchioles probably synthesise other components of surfactant
66
EM of capillaries, endothelium, and type I pneumocytes
67
How to identify type II pneumocytes on histology
Their **nuclei are large and plump** with **dispersed chromatin** and **prominent nucleoli**. The plentiful **eosinophilic cytoplasm** is filled with fine unstained **vacuoles** representing lamellar bodies that are easily visible on TEM.
68
Type II pneumocyte on TEM
69
Lamellar bodies
Bodies are membrane bound and the lamellae within them are composed mainly of phospholipids, particularly **palmitoyl phosphatidylcholine**. Phospholipid is released by exocytosis, spreading out over the alveolar surface where it combines with other carbohydrate- and protein-containing secretory products (some of which are derived from bronchiolar Clara cells) to form a **tubular lattice of lipoprotein described as tubular myelin.**
In the event of two alveolar surfaces coming together, this **overcomes the effects of surface tension which would otherwise cause them to adhere**. This allows for normal inflation of the alveoli at birth and for the reinflation of alveoli which collapse after airway obstruction.
70
If premature delivery is anticipated during pregnancy, administering ___ to the mother induces surfactant production in the fetal lung and reduces the risk of neonatal lung disease.
If premature delivery is anticipated during pregnancy, administering **corticosteroids** to the mother induces surfactant production in the fetal lung and reduces the risk of neonatal lung disease.
71
TEM of the basement membrane in an alveolus
72
Elastin in the alveolar wall
Alveolar walls contain a large amount of elastin, which is condensed to form a supporting ring at the margins of the openings into the alveoli.
73
Elastin on TEM
The elastin El appears as an amorphous, moderately electron-dense mass which is insinuated between the two cell layers.
74
Alveolar epithelial cells vs adenocarcinoma cells
75
TEM of an alveolar macrophage
Alveolar macrophages move freely in alveolar spaces and in the alveolar septa. Their function is the phagocytosis and removal of unwanted material which gains access to the air spaces, such as inhaled particulate matter and bacteria.
After phagocytosing the particles, most macrophages pass into the airways to become trapped in mucus and coughed up as sputum. Others stay in the septa whilst some gain access to the lymphatic system and pass with their phagocytosed material to the hilar lymph nodes.
76
Pneumosilicosis
Silica is inhaled into the air sacs as tiny particles that are phagocytosed by macrophages. Many of these macrophages pass into the bronchial mucus and are expectorated or swallowed.
However, those that remain in the alveolar septa stay there for many years, and the silica is slowly converted into **silicic acid** which stimulates the **proliferation of fibroblasts** and the **production of excess collagen**. The alveolar walls thicken and become fibrotic, interfering with gas exchange, and eventually **lung fibrosis** becomes extensive. Macrophages that reach the lymph nodes carry the particulate matter there and **fibrosis of lymph nodes** may also occur.
77
Bronchiole pulmonary arteries and distal pulmonary arteries
Beyond the point where the bronchi lose their cartilage plates to become bronchioles, the pulmonary arteries become **muscular arteries with distinct elastic laminae** and a **tunica media that is almost completely composed of smooth muscle.** The transition from elastic to muscular arteries is gradual.
The distal pulmonary arteries continue to follow the distribution of bronchioles and become progressively smaller as the **tunica media becomes thinner**, eventually becoming **discontinuous in the pulmonary arterioles.**
78
Underpenetration
When film is not exposed long enough and open spaces, like the lungs, appear white.
79
Overpenetration
The film is exposed too long and even solid spaces filled with bone appear dark.
80
In X-ray imaging, structures that are closer to the light source will appear. . .
. . . **larger.** Because they case a bigger shadow on the film.
81
In a straight-on X-ray, . . .
**. . . the clavicle and first rib should overlap.**
If they do not, you can do some mental rotation to figure out what angle you are looking at.
In a **lordotic** film, the 1st rib will appear below the clavicle.
82
For the purposes of radiologic imaging of the thorax, the patient is told to . . .
. . . **take in a full breath and hold it in.**
This allows us to also assess the extent of the lung span relative to the position of the ribs. The bottom should be between **the 8th and 10th ribs** in a health patient.
83
Conventional radiograph labels
84
Distinguishing lung borders on a radiograph
85
On a good thoracic X-ray, ___ should always be apparent and sharp. Otherwise something may be wrong.
On a good thoracic X-ray, **the costophrenic angles** should always be apparent and sharp. Otherwise something may be wrong.
86
Lateral radiograph orientation
87
The ___ hemidiaphragm ends higher than the ___ hemidiaphragm.
The **right** hemidiaphragm ends higher than the **left** hemidiaphragm.
Because of the liver.
88
ou are examining a patient with pneumonia in the right upper lobe. The best place to listen for the pneumonia, based on your knowledge of anatomy is:
Upper front of the thorax
89
Patients with emphysema often have larger lung volumes at the end of a relaxed exhalation than a healthy individual. In an emphysema patient, you predict that the central tendon of the diaphragm at the end of a relaxed exhalation would be:
Less dome-shaped and lower in the chest
90
Right middle lobe pneumonia with pleural effusion
91
Identify the fissures
92
Normally, the lungs of newborn infants are able to inflate easily at birth because of . . .
. . . **the presence of surfactant which overcomes the surface tension of the collapsed fetal lungs.**
93
Respiratory distress syndrome of the newborn
Surfactant production occurs late in gestation and, **if the infant is born prematurely, there is often insufficient surfactant to allow normal breathing after delivery**. This can result in severe **acute** breathing difficulties as well as persistent **chronic** lung disease in surviving infants.
If premature delivery is anticipated during pregnancy, **administering corticosteroids** to the mother **induces surfactant production** in the fetal lung and reduces the risk of neonatal lung disease.
94
Interstitial pulmonary fibrosis pathophysiology
The **fibroblasts** in the alveolar septa, normally scanty, increase in number and increase their collagen and elastin production. Thi**s thickens the alveolar septum,** interposing layers of collagen **between the cytoplasm of the type I pneumocyte and alveolar capillaries**, thus impeding gaseous exchange. This is a diffuse change throughout the lung and leads to slowly **progressive hypoxia and breathlessness.**
95
Course of the pulmonary artery branches within the lung
The main right and left pulmonary arteries enter the lungs at the lung hila alongside the main bronchi and follow the course of the bronchi into the lungs, dividing into progressively smaller branches as the bronchi divide.
96
Proximal pulmonary arteries
The proximal pulmonary arteries, the main pulmonary trunk and large pulmonary arteries, are elastic arteries similar to the aorta but thinner walled, with elastic fibres an important component of the tunica media.
97
Beyond the point where the bronchi lose their cartilage plates to become bronchioles, the pulmonary arteries become . . .
. . . muscular arteries with distinct elastic laminae and a tunica media that is almost completely composed of smooth muscle. The transition from elastic to muscular arteries is gradual.
98
The small pulmonary arterioles transfer blood into . . .
The small pulmonary arterioles transfer blood into **the pulmonary capillaries**
99
The largest pulmonary veins, that leave the lungs at the hilar regions and pass to the left atrium, show . . .
The largest pulmonary veins, that leave the lungs at the hilar regions and pass to the left atrium, show **elastic fibres scattered in the media, rather than in distinct elastic laminae.**
100
The bronchial arteries are branches of. . .
The bronchial arteries are **lateral branches of the thoracic aorta and run with the bronchial tree as far as respiratory bronchiole level where they anastomose with the pulmonary vascular system.**
101
Anastamoses between pulmonary and systemic circulation
The **bronchial arteries** anastomose with the **pulmonary vascular system** at the **respiratory bronchiole level.** The small **bronchial veins and venules** also anastomose freely with **pulmonary veins and venules** before main bronchial veins drain into the azygos and hemiazygos vein
