Lecture 27 +28 +DLA Flashcards
what germ layers does the respiratory system develop from?
endoderm and mesoderm
Role of the Tracheoesophageal septum?
divide the foregut into the esophagus and trachea
development of the larynx
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
What develops into the respiratory bud
develops from the laryngotracheal diverticulum during
the 4th week.
define atresia, stenosis, and fistula
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)
Atresia with distal fistula
atresia of esophagus
inferior part of the esophagus attaches to the trachea (fistula)
atresia with proximal fistula
the esophagus attaches to the trachea
the inferior esophagus is blocked
tracheoesophageal fistula
complete esophagus, but a part of the esophagus attaches to the trachea
esophageal atresia
blockage of the esophagus
lower esophagus does not attach to the upper portion
atresia with double fistula
the esophagus attaches to the trachea twice
TRACHEO-ESOPHAGEAL FISTULA (TEF) occur why?
signs and symptoms?
occur due to incomplete division of the upper foregut
symptoms:
coughing, choking, pneumonia
polyhydramnios during pregnancy
may be a component of VACTERL
stages of lung devlopment
- pseudo- glandular stage (5-17 weeks) major components of the lung, no bronchioles
- canalicular period (16 to 25 weeks) Type II alveolar cells appear to produce surfactant
- Terminal sac period (24 to birth)
- alveolar period (32 to 8-10 years old)
respiratory distress syndrome
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
prolonged intrauterine asphyxia
irreversible changes in type II cells rendering them incapable of producing surfactant.
factors that influence normal development of the lungs?
- thoracic space for growth (hernia)
- fetal breathing movements
- amniotic fluid volume
Oligohydramnios
to little amniotic fluid
can lead to pulmonary hypoplasia
common sites for diaphragmatic hernia
- anteromedial defect (Defect between costal and
sternal musculature) - central esophageal hiatus (abnormally large)
- posterolateral defect (Defect of pleuroperitoneal
membrane)
congenital diaphragmatic hernia
the lung is compressed and hypoplastic
thoracic space is reduced due to intestinal contents in the thoracic cavity
eventration of diaphragm
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
Septum transversum
partition separates the pericardial and abdominal cavities
surface landmarks for the pleura?
mid-clavicular:
rib 6 to rib 8
mid-axillary line:
Rib 8 to rib 10
paravertebral:
TV 10 to TV 12
pneumothorax and the different types
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
tension pneumothorax and non tension
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
how to decompress tension pneumothorax
need decompression:
2nd intercostal space midclavicular using 14/16 gauge
tube thoracostomy:
4th or 5th intercostal space between the anterior axillary and midaxillary lines.
Where are aspirated/inhaled foreign objects more likely to be lodged
wider, shorter and more vertical right bronchus and eventually in the right lower lobe
Atelectasis
complete or partial collapse of a lung or a section of the lung
dyspnea and coughing
lymphatic drainage of the lung
Intrapulmonary vessels & nodes
- bronchopulmonary (hilar) nodes
- tracheobronchial (carinal) nodes
- paratracheal nodes
- bronchomediastinal lymph trunk
- right thoracic trunk/thoracic duct
- systemic venous system
pneumonia
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
acute pulmonary edema
collection of fluid in the alveoli
Usually due to cardiac failure, but can be due to
cardiogenic shock, toxins, pneumonia or medications
pleural effusion
Collection of excess fluid in the pleural cavity – blunting of the costodiaphragmatic recess
innervation of the lung
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
