17. Thorax II - Lungs

Question 1

What is the first stage of lung development?

Answer 1

The Glandular stage (weeks 5-17), Respiration is not possible, premature fetuses cannot live.

Question 2

What is the second stage of lung development?

Answer 2

The Canalicular stage (weeks 13-25) Respiration is not possible, premature fetuses rarely survive.

Question 3

What is the third stage of lung development?

Answer 3

The Termaninal sac stage (weeks 24-birth). Type I and II pneumocytes are present. Respiration is possible, premature fetuses born between weeks 25-28 can survive with intensive care.

Question 4

What is the forth stage of lung development?

Answer 4

The Alveolar stage (Birth-8 years). Respiratory bronchioles, terminal sacs, alveolar ducts, and alveoli increase in number. Chest radiograph is more dense in children.

Question 5

What is Respiratory distress syndrome?

Answer 5

Caused by surfactant insuficiency (composed of phosphatidylcholine [mainly dipalmitoyl lecithin] and proteins). This condition can be assiciated with premature infants, infants of diabetic mothers, and prolonged intrauterine asphyxia. Thyroxine and cortisol treatment increase the production of surfactant.

Question 6

What is Hyaline membrane diasease?

Answer 6

Surfactant deficiency may lad to hyaline membrane disease whereby repeated gasping inhaltions damage the alveolar lining. Hyaline membrane disease si characterized histologically by collapsed alveoli (actelectasis) and eosinophilic (pink) fluid covering the alveoli.

Question 7

What is difference between parietal pleura and visceral pleura?

Answer 7

Parietal pleura lines the inner surface of the thoracic cavity; visceral pleura follows the contours of the lung itself.

Question 8

What can cause pulmonary hypoplasia?

Answer 8

It is when lung development is stunted. Can be caused by congenital diaphragmatic hernia (herniation fo abdominal contents into the thorax, which compresses the lung) or with bilateral renal agenesis (this causes oligohydramnios, which increases the pressure on the fetal thorax).

Question 9

What is the pleural cavity?

Answer 9

It is the space between the parietal and visceral layers of the pleura. It is a sealed, blind space. The introduction of air into the pleural cavity may cause the lung to collapse (pneumothorax).

Question 10

What makes the serous fluid found in the pleural cavity?

Answer 10

The mesothilia cells of the pleural membrane. It normally contains a small amount of fluid.

Question 11

What are pleural reflections?

Answer 11

They are areas where the pleura change direction from one wall to the other.

Question 12

What is the sternal line of reflection?

Answer 12

It is where the costal pleura is continuos with the mediastinal pleura behind the sternum (from costal cartilage 2-4). The pleural margin then passes inferiorly to the level of the sixth costal cartilage.

Question 13

What is the costal line of reflection?

Answer 13

It is where the costal pleura becomes continuous with the diaphragmatic pleura from rib 8 in the midclavicular line, to rib 10 in the midaxillary line, and to rib 12 laterl to the vertebral column.

Question 14

What are pleural recesses?

Answer 14

They are potential spaces not occupied by lung tissue except during deep inspiration.

Question 15

Describe the costodiaphragmatic recess.

Answer 15

They are the spaces below the inferior borders of the lungs where costal and diaphragmatic pleura are in contact.

Question 16

Describe th costomediastinal recess.

Answer 16

It is the space where the left costal and mediastinal parietal pleura meet, leaving a space caused by the cardiac notch of the left lung. This space is occupied by the lingula of the left lung during inspiration.

Question 17

Where is the bottom of the lung and the bottom of pleura in the midclavicular line?

Answer 17

6th rib, 8th rib respectively.

Question 18

Where is the bottom of the lung and the bottom of pleura in the midaxillary line?

Answer 18

8th rib, 10th rib respectively.

Question 19

Where is the bottom of the lung and the bottom of pleura in the paravertebral line?

Answer 19

10th rib, 12th rib respectively.

Question 20

What does the intercostal nerve innervate in the parietal pleura?

Answer 20

The costal and peripheral portions of the diaphragmatic pleura.

Question 21

What does the phrenic nerve innervate in the parietal pleura?

Answer 21

The central portion of the diaphragmatic pleura and the mediastinal pleura.

Question 22

What is the costal surface?

Answer 22

It is a large convex area related to the inner surface of the ribs.

Question 23

What is the pulmonary ligament?

Answer 23

It is a double fold of the pleura hanging inferior to the root of the lung.

Question 24

What is the hilus and what does it contain?

Answer 24

It si the point of attachment for the root of the lung. It contains the bronchi, pulomary and bronchial vessels, lymphatics and nerves.

Question 25

Which lung has three lobes and what dives each lobe?

Answer 25

The right lobe. The oblique and horizontal fissures.

Question 26

What divides the left lung into two lobes?

Answer 26

The oblique fissure.

Question 27

How many bronchiopulmonary segments are on the right lung and on the left lung?

Answer 27

The right lung has 10; 8 on the left.

Question 28

Where do pulmanry arteries arise from and what do they do?

Answer 28

They arise form the pulmonary trunk. The pulmonary arteries deliver deoxygenated blood to the lungs to the right side of the heart.

Question 29

How many pulmonary veins are there and what do they do?

Answer 29

They are four pulmonary veins: superior right and left, inferior right and left. They carry oxygenated blood to the left atrium of the heart.

Question 30

Where do the bronchial veins drain to?

Answer 30

They drain to the azygos system. They share draingae from the bronchi with the pulmonary veins.

Question 31

Where do the bronchomediastinal lymph trunks drain to?

Answer 31

To the right lymphatic duct and the thoracic duct.

Question 32

Where do the superficial lymphatics of the lung drain to?

Answer 32

To the bronchopulmonary nodes; from there they drain to the tracheobronchial nodes.

Question 33

Where do the deep lymphatics of the lung drain to?

Answer 33

To the pulmonary nodes; from there they drain to bronchopulmonary nodes.

Question 34

What nerve innervastes the anterior and posterior pulmonary plexuses?

Answer 34

The vagal (parasympathetic) and sympathetic fibres.

Question 35

What does a parasympathetic stimulation do to the lung?

Answer 35

Bronchoconstrictor effect.

Question 36

What does a sympathetic stimulation do to the lung?

Answer 36

Bronchodilator effect.