1.
In approximately ______ of development, respiratory diverticulum (lung bud) appears as an outgrowth from the ventral wall of the forgut.
Correct Answer
B. Week 4
Explanation
During the development of the respiratory system, the respiratory diverticulum, also known as the lung bud, emerges as an outgrowth from the ventral wall of the foregut. This occurs in approximately week 4 of development.
2.
Epithelium of the internal lining of the larynx, trachea, bronchi, and lungs is entirely of __________ origin.
Correct Answer
B. Endodermal
Explanation
The correct answer is endodermal. The internal lining of the larynx, trachea, bronchi, and lungs is derived from the endoderm, which is one of the primary germ layers formed during embryonic development. The endoderm gives rise to the epithelial lining of various organs in the respiratory and digestive systems, including the respiratory tract. Therefore, the epithelium of the internal lining of the larynx, trachea, bronchi, and lungs is entirely of endodermal origin.
3.
The cartilagnious, muscular, and connective tissue components of the trachea and lungs are derived from _____________ surrounding the foregut.
Correct Answer
A. Splanchnic mesoderm
Explanation
The correct answer is splanchnic mesoderm. The trachea and lungs develop from the foregut during embryonic development. The splanchnic mesoderm is the layer of mesoderm that surrounds the foregut and gives rise to the cartilaginous, muscular, and connective tissue components of the trachea and lungs. The endodermal layer gives rise to the epithelial lining of the trachea and lungs, while neural crest cells are not involved in the development of these structures. Therefore, the correct answer is splanchnic mesoderm.
4.
Initially, the lung bud is in open communication with the foregut.
Correct Answer
A. True
Explanation
Tracheoesophageal septum divides the foregut into a dorsal portion: the esophagus and a ventral portion: the trachea and lung buds.
5.
Trachea and esophagus are derived from the foregut via lung buds.
Correct Answer
A. True
Explanation
lung buds forms the trachea and two lateral outpocketings: the bronchial buds.
6.
_________________ is a complication of tracheoesophageal fistulas (TEF); amniotic fluid does not pass down to stomach and intestine.
Correct Answer
B. Polyhydromnios
Explanation
Esophageal atresia with or without tracheoesophageal fistulas (TEF) causes polyhydromnios.
7.
VACTERL association are a group of disorders that are found together.
(V) vertebral anomalies
(A) anal atresia
(C) cardiac defects
(T) tracheoesophageal fistula
(E) esophageal atresia
(R) renal anomalies
(L) limb defects
Correct Answer
A. True
Explanation
The VACTERL association refers to a group of congenital disorders that often occur together. These disorders include vertebral anomalies, anal atresia, cardiac defects, tracheoesophageal fistula, esophageal atresia, renal anomalies, and limb defects. Therefore, the statement that VACTERL association disorders are found together is true.
8.
Within the 4th week, communication between the thorax and abdomen is via _______________________.
Correct Answer
C. Pericardio peritoneal canals
Explanation
During the 4th week of development, the communication between the thorax and abdomen occurs through the pericardio peritoneal canals. These canals allow for the passage of structures such as blood vessels and nerves between the two regions. The phrenic nerve and common cardinal veins are not specifically involved in this communication pathway during this stage of development. Therefore, the correct answer is pericardio peritoneal canals.
9.
Splanchnic mesoderm covers the outside of the lung, develops into the visceral pleura.
Correct Answer
A. True
Explanation
The somatic mesoderm which covers the body wall from the inside becomes the parietal pleura.
10.
By the end of the 6 month approximately 17 generations of the subdivisions have formed in the lungs.
Correct Answer
A. True
Explanation
Before the bronchial tress reaches it final shape, an additional six divisions form during postnatal life.
11.
Bronchopulmonary segments are the largest subdivision of a lobe. It has its own bronchus, artery and veins. And can be separated surgically.
Correct Answer
A. True
Explanation
Bronchopulmonary segments are indeed the largest subdivision of a lobe. Each segment has its own bronchus, artery, and veins, which allows for independent functioning. This anatomical arrangement also enables surgeons to separate and remove individual segments if necessary. Therefore, the statement is true.
12.
Branching is regulated by epithelial mesenchymal interactions between the endoderm of the lung bud and ______________ that surrounds them.
Correct Answer
A. Splanchnic mesoderm
Explanation
During lung development, branching is controlled by interactions between the endoderm of the lung bud and the surrounding splanchnic mesoderm. The splanchnic mesoderm provides signals and cues that guide the branching and differentiation of the lung bud. This interaction is crucial for the proper formation and organization of the lung tissue. Neural crest cells and ectoderm do not play a direct role in this process.
13.
Congenital diaphragmatic hernia is when the pleuroperitoneal folds fail to form properly,a large opening called the foramen of Bochdalek develops in the posterolateral region of the diaphargm. In these cases substantial small bowel loops are present in the thoracic cavity through the incomplete separation of the pleural and peritoneal cavities. The degree of survivial is depended on _____________.
Correct Answer
A. Degree of pulmonary hypoplasia
Explanation
The presense of the bowel in the chest hinders formation of the lungs leading to pulmonary hypoplasia (which decrease the alveolar surface area for gas exchange). The diaphragmatic hernia is repaired surgically.
14.
Branching has continued to form terminal bronchioles. No respiratory bronchioles or alveoli are present. No gas exchange and not compatible to life.
Correct Answer
A. Week 5 to 16 (pseudoglandular period)
Explanation
During the pseudoglandular period, which occurs between week 5 to 16 of fetal development, branching has continued to form terminal bronchioles. However, respiratory bronchioles and alveoli have not yet developed. Without respiratory bronchioles and alveoli, there is no gas exchange, which is essential for sustaining life. Therefore, this period is not compatible with life.
15.
Each terminal bronchiole divides into two or more respiratory bronchioles, which in turn divide into 3 to 6 alveolar ducts; too thick for gas exchange
Correct Answer
B. Week 16 to 26 (canalicular period)
Explanation
During the canalicular period, which occurs between week 16 to 26 of fetal development, the respiratory bronchioles divide into 3 to 6 alveolar ducts. These alveolar ducts are too thick for efficient gas exchange to occur. This period is characterized by the development of the lung's vascular network and the appearance of type II pneumocytes, which are responsible for producing surfactant. Therefore, the thick alveolar ducts during the canalicular period make them unsuitable for gas exchange.
16.
The cuboidal respiratory bronchioles change into thin, flat cells. these cells are intimately associated with numerous blood and lymph capillaries, and the surrounding spaces are now known as primitive alveoli. Respiration becomes possible.
Correct Answer
C. Week 26 to birth (terminal sac period)
Explanation
During the week 26 to birth, which is known as the terminal sac period, the type II pneumocytes first appear. These cells are responsible for producing surfactant, a substance that reduces surface tension in the alveoli and prevents them from collapsing. The development of type II pneumocytes is crucial for the proper functioning of the respiratory system and allows for respiration to occur. Therefore, the given answer is correct.
17.
Type II pneumocytes first appear and begin to secrete surfactant, at ________.
Correct Answer
C. Week 28
Explanation
Type II pneumocytes first appear and begin to secrete surfactant at week 28. Surfactant is a substance that reduces surface tension in the alveoli of the lungs, preventing them from collapsing and aiding in the exchange of gases. The development and secretion of surfactant by type II pneumocytes is crucial for the proper functioning of the respiratory system. Therefore, by week 28, the presence of type II pneumocytes and the secretion of surfactant play a significant role in the maturation of the lungs and the preparation for independent breathing after birth.
18.
During the 7th month of development, sufficient numbers of capillaries are present to guarantee adequate gas exchange, and the premature infant is able to survive.
Correct Answer
A. True
Explanation
During the 7th month of development, the premature infant has developed enough capillaries to ensure proper gas exchange. This means that oxygen can be delivered to the body's tissues and carbon dioxide can be removed effectively. As a result, the premature infant is able to survive outside of the womb.
19.
The number of terminal sacs increases steadily. Type I pneumocytes become thinner, so that surrounding capillaries protrude into the alveolar sacs. This intimate contact between epithelial and endothelial cells makes up the blood air barrier. Mature alveoli are not present before birth.
Correct Answer
A. Alveolar period (8months to childhood)
Explanation
Before birth, the lungs are full of fluid. The amount of surfactant in the fluid increases particulary during the last 2 weeks before birth. After birth, growth of the lungs are primarily due to an increase in the number of respiratory bronchioles and alveoli.
20.
It is estimated that only 1/6 of the adult numbe of alveoli are present at birth. The remaining alveoli are formed during the first 10 years of postnatal life through the continuous formation of new primitive alveoli.
Correct Answer
A. True
Explanation
The explanation for the given correct answer is that alveoli, which are tiny air sacs in the lungs responsible for gas exchange, continue to form and develop after birth. It is estimated that only 1/6 of the total adult number of alveoli are present at birth. The remaining alveoli form during the first 10 years of postnatal life through the continuous formation of new primitive alveoli. Therefore, it is true that the majority of alveoli are formed after birth.
21.
Fetal breathing movements begin at birth and cause aspiration of amniotic fluid.
Correct Answer
B. False
Explanation
Fetal breathing movements begin before BIRTH.
22.
Fetal breathing movements are important for stimulating _____________ and ________________.
Correct Answer
C. Lung development; conditioning respiratory muscles
Explanation
Fetal breathing movements are important for stimulating lung development and conditioning respiratory muscles. These movements help in the maturation of the lungs and the development of the respiratory system. They also aid in strengthening the respiratory muscles, which are essential for proper breathing after birth.
23.
When respiration begins at birth, most of the fluid in the lungs is rapidly absorbed by the _________ and ____________.
Correct Answer
A. Blood and lympH capillaries
Explanation
a small amount of fluid is expelled via trachea and bronchi during delivery
24.
With air entering the lungs during the first breath, _____________ is needed to prevent the avleoli from collasping.
Correct Answer
C. Surfactant
Explanation
When the lung fluid is absorbed from alveolar sac, surfactant remains deposited as a thin phospholipid coat on alveolar cells membrane. Without surfactant layer, the alveoli would collapse during expiration (atelectasis).
25.
Respiratory distress syndrome (RDS) is when a surfactant is insufficient, alveoli will collapse during expiration.
Correct Answer
A. True
Explanation
Respiratory distress syndrome (RDS) is a condition characterized by insufficient surfactant in the lungs. Surfactant is a substance that helps reduce surface tension in the alveoli, preventing them from collapsing during expiration. Therefore, if there is not enough surfactant, the alveoli will indeed collapse during expiration. Hence, the statement "Respiratory distress syndrome (RDS) is when a surfactant is insufficient, alveoli will collapse during expiration" is true.
26.
With recent development of artificial surfactant and treatment of premature babies with glucocorticoids to stimulate surfactant production have reduced the mortality associated with RDS and allowed survival of some babies as young as 5.5 months of gestation.
Correct Answer
A. True
Explanation
glucocorticoids used to stimulate the type II pneumocytes.
27.
Dilation of terminal or larger bronchi giving the lung a honeycomb appearance on radiograph.
Correct Answer
B. Congenital cysts of the lung
Explanation
Congenital cysts of the lung can cause dilation of terminal or larger bronchi, resulting in a honeycomb appearance on a radiograph. This condition is present from birth and involves the formation of fluid-filled sacs in the lung tissue. These cysts can lead to respiratory symptoms and may require medical intervention. Ectopic lung lobes, emphysema, and cirrhosis are unrelated conditions and would not cause the honeycomb appearance seen in congenital cysts of the lung.