13. Respiratory System and Thoracic Cavities Flashcards

1
Q

Laryngotracheal groove forms from the 6th arch, is the primitive pharynx, on the outside of the groove what is it called? (2 names )

A

Called the laryngotracheal diverticulum or lung bud (respiratory diverticulum) outside of embryo

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2
Q

What is the orientation of the esophagus and the trachea at the beginning of formation?

A

the trachea is anterior to the esophagus

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3
Q

How are the trachea and the esophagus separated?

A

tracheoesophagela folds

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4
Q

There are indentation on either side of the tube, the folds will then fuse in the midline, it forms the?

A

tracheoesophageal septum, separating esophagus from the larynx

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5
Q

When are the laryngotracheal diverticulum and the tracheoesophageal septum formed?

A

4th and 5th week

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6
Q

What is important to notice of the tracheoesophageal ridge and why?

A

It is very long/longitudinal. Defects will be formed d/t it

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7
Q

Where does the larynx come from?

A

the forgut endoderm, laryngotracheal groove (6th pharyngeal arch (4/6 are considered together, there is no 5th arch))

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8
Q

What is the first thing seen in the formation of the larynx?

A

Bilateral arytenoid swellings, which are endoderm covered in mesenchyme (neural crest), which diverge into cartilage

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9
Q

What do the arytenoid swellings do?

A

They grow towards tongue, converting groove to T shaped opening called the glottis (opening/space for air to get through to vocal cords)

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10
Q

Hypobranchial/Hypopharyngeal eminence found in arches 3/4, looking at arch 4. What do you see forming in this area?

A

formation of the epiglottis

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11
Q

While the arytenoid swellings are converging, the endoderm proliferates and fills up the glottis, then undergoes apoptosis and that is when you get_____?

A

recanalization, which is complete by week 10, afterwards there is a space/opening to get into lungs

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12
Q

What else does recanalization form within the larynx?

A
Laryngeal ventricles (later)
Vocal and vestibular folds
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13
Q

What congenital abnormality occurs when recanilization (apoptotic process) has failed during week 10. They present with asphyxia at the time of birth and have obstruction of the upper fetal airway?

A

Laryngeal Atresia

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14
Q

What congenital abnormality occurs when there is incomplete atresia and tissue between vocal folds, which block the glottis. Present with respiratory distress, unusual cry and stridor (high pitched cry)? Caused by failure of recanalization in week 10

A

Laryngeal webs

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15
Q

What congenital abnormality occurs when there is collapse of the supraglottic structures during inspiration (epiglottis, arytenoid cartilage). Mechanism unknown, making it difficult to breath.

A

Laryngomalacia

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16
Q

Trachea, which is inferior to the larynx, comes from endoderm and splanchnic mesenchyme. What does each form (2 &3)

A

Endoderm: Epithelium and glands of trachea
Pulmonary epithelium
Splanchnic: Cartilage rings trach, CT, Smooth muscles

17
Q

What congenital abnormality occurs when there is esophageal atresia (blind end esophagus (no passage way)) and tracheoesophageal fistula (abnormal passage between trachea and esophagus)? Patient is cyanotic, gag/difficulty feeding d/t food in airways. Can be dianosed using nasogastric tube: only 12 cm tubing will fit when usually it is 17cm

A

Tracheoesophageal fistula

18
Q

What embryological disfucntion occurs for tracheoesophageal fistula to occur?

A

Tracheoesophogeal folds malfunction and did not divide everything appropriately during week 5

19
Q

The lung bud (respiratory diverticulum) forms in week 4. The lung forms into primary bronchial buds during week 5, primary branch into secondary and secondary branch into tertiary bronchial buds during what weeks?

A

Secondary (three on right, two on left) during week 6

Tertiary (10 right, 9 left) during week 7

20
Q

What does the endoderm for bronchi grow into during formation?

A

into splanchnic mesoderm, which extends into the pericardial/peritoneal canals (space)

21
Q

What forms in the lungs after 24 weeks gestation, finishing the formation of the conduction system?

A

Terminal bronchioles are formed (17 orders of branches)

22
Q

What are the four stages of lung development and what weeks do they occur in? (weeks overlap)

A

Psuedoglandular (5wks-17)
Canalicular (16wks-25)
Terminal sac (Saccular) (24wks-birth)
Alveolar (32wks-8years)

23
Q

Female lungs develop before male lungs. African american lungs develop before caucasian lungs. What about region of the lungs and development?

A

Superior aspect of lungs develop before inferior aspect of lungs

24
Q

During the pseudoglandular (5-17) region, the terminal bronchioles are formed with terminal sacs. What is it surround by and cant the infant survive if born?

A

Surrounded by splanchnic CT with capillaries far from the bronchioles, so no gas exchange can occur, infant dies

25
Q

During the canalicular stage (16-25), terminal bronchioles branch to form respiratory bronchioles, which divide to form the primordial alveolar ducts. Can an infant survive if born during this time?

A

If the infant is born during weeks 22-25 can survive, if weeks 16-19 probably will not survive, due to no gas exchange / gas exchange availible

26
Q

During the terminal sac or saccular stage (24wks-birth), gas exchange occurs more effectively. This occurs due to formation of squamous epithelium which forms __________ and the secretory epithelial cells which form________ which does what?

A

type I pneumocytes which assist in gas exchange

Type II pneumocytes which provide surfactant to prevent atalectasis (collpased alveoli)

27
Q

During the alveolar stage (32wks - 8years), formation of alveolar capillary membrane consisting of endoderm and mesoderm. There are some primitive alveoli, however when do most of mature alveoli form?

A

95% of alveoli form after birth til 3 years, this is why it is so important to not be exposed to smoking/chemicals in younger ages because can damage lungs!

28
Q

Fetal breathing movements are essential for lung development. We need three things for normal lung development, what are they?

A
  1. Fetal breathing movements
  2. Adequate thoracic space
  3. Adequate level of amniotic fluid
29
Q

How is intra alveolar fluid cleared via vaginal birth and c-section?

A

Vaginal: pressure of vaginal helps expell fluid through mouth and nose
Csection: Fluid goes into pulmonary capillaries,arteries, veins, and lymphatics to be drained

30
Q

What is oligohydramnios? What can it cause?

A

too little of amniotic fluid, causing malformation of lungs and can result in pulmonary hypoplasia (risk increases prior to 26 weeks)

31
Q

What are some signs and symptoms of respiratory distress? (5)

A
Tachypnea
Nasal flaring
Suprasternal, intercostal or subcostal retractions
Grunting
Cyanosis
32
Q

What disease is characterized as having diffuse reticulogranular ground glass appearance (fuzzy white where it should be dark for air in lungs)?

A

Hyaline Membrane Disease (respiratory distress syndrome)

33
Q

What causes hyaline mebrane disease/respiratory distress syndrome?

A

There is no air due to a lack of surfactant from the type II pneumocytes in the terminal sac stage. (surfactant allows air to be taken up into the lungs)

34
Q

If patient presents with congenital diaphragmatic hernia (foramen of bochdalek) due to failure of the septum transversum/ plueroperitoneal fold to fuse during week 6, what can we expect to see? (4)

A

Chest will be barrel shaped d/t intestines in left cavity
Abdomen is sunk in
No breath sounds in normal area
No heartbeat in appropriate area

35
Q

Polyhydramnios (too much amniotic fluid), right after birth baby has excissive secretions from mouth, choking coughing and respiratory distress. What defect is present and how?

A

Tracheoesophageal fistula, due to tracheoesophageal septum and folds not fusing during week 5

36
Q

What are the different types of lung cysts that are though to resolve from a disturbance in bronchial development during late fetal life?

A

Air and fluid cysts