Lecture 27 +28 +DLA

Question 1

what germ layers does the respiratory system develop from?

Answer 1

endoderm and mesoderm

Question 2

Role of the Tracheoesophageal septum?

Answer 2

divide the foregut into the esophagus and trachea

Question 3

development of the larynx

Answer 3

laryngeal epithelium develops from the endoderm of the cranial part of the laryngotracheal tube

laryngeal cartilage develops from neural crest cells

muscles develop from the myoblasts

all come from the 4th and 6th pairs of pharyngeal arches

Question 4

What develops into the respiratory bud

Answer 4

develops from the laryngotracheal diverticulum during

the 4th week.

Question 5

define atresia, stenosis, and fistula

Answer 5

atresia: obstruction or blockage (failure of recanalization of the lumen)
stenosis: narrowing of lumen (unequal partitioning of the foregut)
fistula: abnormal passage (. incomplete division of cranial part of foregut into respiratory system and esophagus)

Question 6

Atresia with distal fistula

Answer 6

atresia of esophagus

inferior part of the esophagus attaches to the trachea (fistula)

Question 7

atresia with proximal fistula

Answer 7

the esophagus attaches to the trachea

the inferior esophagus is blocked

Question 8

tracheoesophageal fistula

Answer 8

complete esophagus, but a part of the esophagus attaches to the trachea

Question 9

esophageal atresia

Answer 9

blockage of the esophagus

lower esophagus does not attach to the upper portion

Question 10

atresia with double fistula

Answer 10

the esophagus attaches to the trachea twice

Question 11

TRACHEO-ESOPHAGEAL FISTULA (TEF) occur why?

signs and symptoms?

Answer 11

occur due to incomplete division of the upper foregut

symptoms:
coughing, choking, pneumonia
polyhydramnios during pregnancy

may be a component of VACTERL

Question 12

stages of lung devlopment

Answer 12

1. pseudo- glandular stage (5-17 weeks) major components of the lung, no bronchioles
2. canalicular period (16 to 25 weeks) Type II alveolar cells appear to produce surfactant
3. Terminal sac period (24 to birth)
4. alveolar period (32 to 8-10 years old)

Question 13

respiratory distress syndrome

Answer 13

can be due to surfactant deficiency
the lungs collapse when no surfactant is produced

thus rapid labored breathing is seen after birth

surfactant reduces surface tension and helps with expansion of terminal sacs

Question 14

prolonged intrauterine asphyxia

Answer 14

irreversible changes in type II cells rendering them incapable of producing surfactant.

Question 15

factors that influence normal development of the lungs?

Answer 15

1. thoracic space for growth (hernia)
2. fetal breathing movements
3. amniotic fluid volume

Question 16

Oligohydramnios

Answer 16

to little amniotic fluid

can lead to pulmonary hypoplasia

Question 17

common sites for diaphragmatic hernia

Answer 17

1. anteromedial defect (Defect between costal and
   sternal musculature)
2. central esophageal hiatus (abnormally large)
3. posterolateral defect (Defect of pleuroperitoneal
   membrane)

Question 18

congenital diaphragmatic hernia

Answer 18

the lung is compressed and hypoplastic

thoracic space is reduced due to intestinal contents in the thoracic cavity

Question 19

eventration of diaphragm

Answer 19

Caused by a defective musculature in one half of diaphragm due to failure of the muscle tissue from body wall to extend into the pleuroperitoneal membrane

Question 20

Septum transversum

Answer 20

partition separates the pericardial and abdominal cavities

Question 21

surface landmarks for the pleura?

Answer 21

mid-clavicular:
rib 6 to rib 8

mid-axillary line:
Rib 8 to rib 10

paravertebral:
TV 10 to TV 12

Question 22

pneumothorax and the different types

Answer 22

pneumothorax is the presence of air in the pleural cavity

spontaneous: Absence of lung disease, no prior
provoking event, ruptured bleb or bullae

traumatic: introduction of air in the pleural cavity due to injury

other causes:
smoking, inflammation, pulmonary disease

can be tension or non-tension

Question 23

tension pneumothorax and non tension

Answer 23

tension: build up of pressure
displacement of structures of the mediastinum due to accumulation of air in the pleural cavity

compression of heart and great vessels

symptoms:
dyspnea, chest pain, tracheal deviation, hypotension

non-tension = no build up in pressure

Question 24

how to decompress tension pneumothorax

Answer 24

need decompression:
2nd intercostal space midclavicular using 14/16 gauge

tube thoracostomy:
4th or 5th intercostal space between the anterior axillary and midaxillary lines.

Question 25

Where are aspirated/inhaled foreign objects more likely to be lodged

Answer 25

wider, shorter and more vertical right bronchus and eventually in the right lower lobe

Question 26

Atelectasis

Answer 26

complete or partial collapse of a lung or a section of the lung

dyspnea and coughing

Question 27

lymphatic drainage of the lung

Answer 27

Intrapulmonary vessels & nodes

• bronchopulmonary (hilar) nodes
• tracheobronchial (carinal) nodes
• paratracheal nodes
• bronchomediastinal lymph trunk
• right thoracic trunk/thoracic duct
• systemic venous system

Question 28

pneumonia

Answer 28

the normal airfilled spaces of the alveoli become filled with denser material like fluid or pus

cough, fever, chest pains, can be lobar or entire lung

Question 29

acute pulmonary edema

Answer 29

collection of fluid in the alveoli

Usually due to cardiac failure, but can be due to
cardiogenic shock, toxins, pneumonia or medications

Question 30

pleural effusion

Answer 30

Collection of excess fluid in the pleural cavity – blunting of the costodiaphragmatic recess

Question 31

innervation of the lung

Answer 31

Parasympathetics from vagus n. bronchoconstriction, vasodilation and increased mucus secretion by glands

Sympathetics from sympathetics trunks via the cardiopulmonary nerves bronchodilation(beta receptors) and vasoconstriction