Respiratory System Flashcards
What is the lower respiratory system
Larynx, trachea, bronchi, and lungs
When does the lower respiratory system begin to develop
4th week
The respiratory system starts as a median outgrowth-the ___ ___-that appears in the floor of the caudal end of the primordial pharynx
Laryngotracheal groove
The primordium of the tracheobronchial tree develops ___ to the __ pair of pharyngeal pouches
Caudal
Fourth
What does the endodermal lining of the laryngotracheal groove give rise to
Pulmonary epithelium and glands of the larynx, trachea, and bronchi
What does the splanchnic mesoderm surrounding the foregut make
CT, cartilage, smooth muscle
Signaling pathways of __, __, and ___ control patterning of the expression of __ and __ in the early foregut for the differentiation of the trachea from the esophagus.
BMP, Wnt, and FGF
Sox2 and NKx2.1in
In ventral areas, __ is activated while _ is suppressed
Nkx2.1
Sox2
By the end of the 4th week, the laryngotracheal groove has evaginated to form a pouch like ___ ____, which is located ventral to the caudal part of the foregut
Laryngotracheal diverticulum
As the diverticulum elongates, its distal end enlarges to form a globular ___ ___
Respiratory bud
The laryngotracheal diverticulum soon separates from the __ __, but it maintains communication with it through the ___ ___ ___
Primordial pharynx
Primordial laryngeal inlet
As hte diverticulum elongates, it is invested with __ ___
Splanchnic mesoderm
Longitudinal tracheoesophageal folds develop in the laryngotracheal diverticulum, approach each other, and duse to form a partition - the ___ ____
Tracheoesophageal septum
The tracheoesophageal septum divides the cranial part of the foregut into a ventral part, the ___ ___ and a dorsal part, the ___
Laryngotracheal tube(primordium of the Arnce , trachea, bronchi, and lungs
Primordium of the oropharynx and esophagus
The opening of the laryngotracheal tube into the pharynx becomes the ___ ___ __
Primordial laryngeal inlet
The epithelial lining of the larynx develops from the ___ of the cranial end of the laryngotracheal tube
Endoderm
The cartilages of the larynx develop from cell populations int he __ and __ pairs of pharyngeal arches
4 and 6
The laryngeal cartilages develop from the mesenchyme that is derived from ___
Ncc
The mesenchyme at the cranial end of the laryngotracheal tube proliferates rapidly, producing paired __ ___
Arytenoid swellings
These swellings grow toward the tongue, converting the __ __ into a t shaped ___ ___
Primordial glottis
Laryngeal inlet
The laryngeal epithelium proliferates rapidly, resulting in temporary occlusion of the laryngeal lumen.
Ok
Recanalization of the larynx occurs by the __ week
10
The laryngeal ventricles form during their recanalization process. These recesses are bound by folds of mucous membrane that evolve into the __ __ and ___ ___
Vocal folds(cords) and vestibularfolds
The ___ develops from the caudal part of the hypopharyngeal eminence, a prominence produced by the proliferation of the mesenchyme in the ventral ends of the third and fourth pharyngeal arches
Epiglottis
The rostral part of the eminence forms the posterior third of pharyngeal part of the tongue
Ok
The laryngeal muscles develop from ___ in the __ and __ pairs of pharyngeal arches and are therefore innervated by what
Myoblasts 4 and 6
Laryngeal branches of the vagus nerves t
Growth of the larynx and epiglottis is rapid during the firs __ years after birth, by which time the epiglottis has reached its adult form and position
3
Laryngeal atresia
Rare
Obstruction of the upper fetal airway bc of congenital high airway obstruction syndrome
In laryngeal atresia, distal to the atresia or stenosis, the airway becomes ___, the lungs are ____, the diaphragm is ___ or ____ and _____ or ____ is present
Dilated
Hyperplastic
Flattened or inverted
Fetal hydrops or ascites
How diagnose laryngeal atresia
Prenatal ultrasound
The endodermal lining of the laryngotracheal tube distal to the larynx differentiates into the epithelium of ___ of the trachea and ____ epithelium
Glands
Pulmonary
The cartilage, CT, and muscles of the trachea are derived from the ___ ___ surrounding the laryngotracheal tube
Splanchnic mesoderm
Tracheoesophageal fistula
Abnormal passage between the trachea and esophagus
1/3000
Males
In most cases TEF is associated with __ __
Esophageal atresia
TEF results from incomplete division of the cranial part of the foregut into the ___ and ____ parts during the __ week
Respiratory
Esophageal
4th
Incomplete fusion of the tracheoesophageal folds result in a defecting ___ __ and communication between the trachea and esophagus
Tracheoesophageal septum
__ is the most common anomaly of the lower respiratory tract
TEF
Esophageal atresia
Blind ending of the superior part of the esophagus
Usual TEF
Esophageal atresia and a joining of the inferior part to the trachea near its bifurcation
Infants with usual TEF
Cough and choke when swallowing
Regurgitate milk
Gastric reflux into trachea and lungs
___ is often associated with esophageal atresia
Polyhydramnios
Why polyhydramnios with esophageal atresia
Excess amniotic fluid accumulates bc fluid cant pass to the stomach and intestines for absorption and subsequent transfer through the placenta to the maternal blood for disposal
Stenosis and atresia of the trachea are uncommon and associated with __
TEF
What causes stenosis and atresia of the trachea
Partitioning of the foregut into he esophagus and trachea
Incomplete tracheal atresia
A web of tissue obstructs airflow
The respiratory bud develops at the caudal end of the ___ ___ during the __ week
Laryngotracheal diverticulum
4th
The respiratory bud don divides into two outpouchings-__ __ __
Primary bronchial buds
Later, __ and ___ bronchial buds form and grow laterally into the pericardioperitoneal canals
Secondary and tertiary
Together with the surrounding splanchnic mesoderm, the bronchial buds differentiate into the __ and their ramifications in the lungs
Bronchi
Early in he __ week the Connection of each bronchial bud with the trachea enlarges to form the primordia of main bronchi
4
The main bronchi subdivide into secondary bronchi that form __, ___ and ____ branches
Lobar
Segmental
Intrasegmental
On the right, the superior secondary bronchus supplies the upper lobe of the lung, whereas the inferior secondary bronchus subdivides I tot he bronchi, one connecting to the middle lobe of the right lung and the other connecting to the lower lobe
On the left the two secondary bronchi supply the upper and lower lobes of th Leung,. Each secondary bronchus undergoes progressive branching
How many segmental bronchi are there int he right and left and when do they begin to form
10 right
8-9 left
7th week
As the segmental bronchi form, the surrounding __ also divides
Mesenchyme
Each segmental bronchus, with its surrounding mass of mesenchyme, is the primordium of a ___ ___
Bronchopulmonary segment
By 24 weeks, approcimately ___ orders of branching have occurred and respiratory bronchioles have developed
17
An additional __ orders of airways develop after birth
7
As the bronchi develop,, cartilaginous plates are formed from the surrounding ___ ___
Splanchnic mesoderm
The bronchial smooth muscle nd CT and the pulmonary CT and capillaries are also derived from the ___
Mesenchyme
As the lungs develop, they acquire a layer of ___ __ from the ___ ___
Visceral pleura
Splanchnic mesoderm
With expansion, the lungs and pleural cavities grow caudally into the mesenchyme of the body wall and soon lie close to the ___
Heart
The thoracic body wall becomes lined by a layer of ___ ___ derived from the __ ___
Parietal pleura
Somatic mesoderm
The space between the visceral and parietal pleura is the ___ ___
Pleural cavity
What are the four stages of lung maturation
Pseudoglandular
Canalicular
Terminal saccular
Alveolar
When is the pseudoglandular period
5-17 weeks
During the pseudoglandular phase, the developing lungs resemble an _____ ____
Exocrine gland
By 16 weeks, all of the major elements of the lung have primed, except what
Those involved with gas exchange
What happens if a fetus is born during the pseudoglandular phase
Die cant breathe respiratoion is not possible
When is the canalicular period
16-25 weeks
Why does the canalicular period overlap the pseudoglandular phase
Cranial segments of the lungs mature faster than caudal segments
In the canalicular period, the lumina of the bronchi and the terminal bronchioles become ___ and the lung tissue becomes __ ___
Larger
Highly vascular
By 24 weeks, each terminal bronchiole has given rise to two or more __ ___, each of which then divides into three to six tubular passages-___ ___ ___
Respiratory bronchioles
Primordial alveolar ducts
Respiratorion is possible toward the end of the canalicular stage because Moe thin walled __ ___ have developed at the ends of the respiratory bronchioles and the lung tissue is well vascularized
Terminal sacs
What happens if a fetus is born 24-26 weeks
May survive if given intensive care, it often dies because its respiratory and other systems are relatively immature
Terminal saccular period. When
24 weeks until late fetal period
During the terminal saccular period, many more __ ___ develop an their epithelium becomes very ___
Terminal sacs (primordial alveoli Thin
In their terminal saccular period, capillaries begin to bulge into these space. The intimate contact between epithelial and endothelial cells, establish the __ ___ ___, which permits adequate gas exchange for survival
Blood-air barrier
The 26 weeks, the terminal sacs ar lined mainly by squamous epithelial cells of the endodermal origin-___ __ ___-across which gas exchange occurs
Type I pneumocytes
Int he remains saccular period, the capillary networks proliferates rapidly in the mesenchyme around the developing alveoli, and there is concurrent active development of __ ___
Lymphatic capillaries
In their terminal sac period, scattered among the squamous epithelial cellls are rounded secretory epithelial cells-__ _ ___, which secrete __ ___,
Type II pneumocytes
Pulmonary surfactant
What is surfactant
Complex mixture of phospholipids and proteins
Surfactant forms a monomolecular film over the interior walls of the alveolar sacs and counteracts surface tension forces at the air-alveolar interface. This facilitates ___ of the terminal sacs
Expansion
The maturation of alveolar type II cells and the production of surfactant vary widely in fetish’s of different ages. When does surfactant production begin
20-22 weeks
But surfactant does not reach adequate levels until when
Late fetal period
When babies are born during the terminalsaccular period, both increased surfactant production , induced by antenatal corticosteroids, and ___ ___ __ ___ have increased the rates of survival of these infants
Postnatal surfactant replacement therapy
When is the alveolar period
Late fetal period to 8 years
At the beginning of the alveolar period, each respiratory bronchiole terminates in a cluster of thin walled terminal space that are separated from one another by loose ___
CT
These terminal space represent future __ ___
Alveolar ducts
The _____ ____ is sufficiently thin to allow gas exchange
Alveolocapillary membrane
The transition from dependence ont he placenta for gas exchange to autonomous gas exchange after birth requires the following adaptive changes int he lungs
Production of surfactant int he alveolar space
Transformation of the lungs into gas exchanging organs
Establishment of parallel pulmonary and systemic circulations
__% of mature alveoli mdevelop in the the post natal period
95
Before birth, the primordial alveoli appear as small bulges on the walls of the respiratory bronchioles and alveolar sacs
After birth the primordial alveoli enlarge as the lungs expand, however most of the increase in the size of the lungs results from a continues increase in the size of the alveoli
Alveolar development is largely complete by _ years of age, but new alveoli may be added until _ years
3
8
Unlike mature alveoli, immature alveoli have the potential for forming additional primordial alveoli
Ok
Approximately __ million primordial alveoli, one half the number in adults are present in the lungs of full term neonates
150
On chest radiographs, the lungs on neonates appear __ than adults
Denser
Between the 3rd and 8th years, the adult complement of __ million alveoli is achieved
300
Three factors are essential for normal lung development
Adequate thoracic space for lung growth adequate amniotic fluid volume
Fetal breathing movements
The mechanism modulating lung morphogenetic and formation of blood vessels int he lungs involved the transcription factors __ and ___ signaling
Sox17
Wnt
Fetal breathing movement occur ___ birth, exerting sufficient force to cause aspiration of some amniotic fluid into the lungs
Before
These fetal breathing movement soccur approximately 50% of the time and only during ___
REM sleep
Fetal breathing movements stimulate lung development
By the time the fetus is born it has several moths of breathing exercise
FETAL BREATHING MOVEMENTS INCREASE AS THE TIME OF DELIVERY APPROACHES
Ok
At birth the lungs are ___ filled with fluid from the amniotic cavity, lungs and tracheal glands
Half
How does aeration fothe lungs at birth occur
Rapid replacement of intralveolar fluid by air
What are the three routes by which the lungs are cleared at birth
Through the mouth and nose by pressure on the thorax during vaginal delivery
Into the pulmonary capillaries and pulmonary arteries and veins
Into the lymphatic vessels
Oligohydramnios
Insufficient amount of amniotic fluid
When oligohydramnios is severe and chronic, lung development is ___
Restarded
Why does oligohydramnios retard lung growth
Reduced hydraulic pressure int he lungs and its consequently effects on lung calcium regulation may result in pulmonary hypoplasia
RDS effects _% of live newborns
2
Who is most susceptible to rds
Premature babies
Another name for rds
Hyaline membrane disease
What is the major cause orf rds
Surfactant defiency
Prolonged intrauterine ____ may produce irreversible changes in type II alveolar cells, making them incapable of producing surfactant
Asphyxia
___ are potent stimulators of fetal surfactant production and may be given to the mother if early delivery is a risk
Corticosteroids
Describe breathing of baby with rds
Rapid, labored breathing
__% of all neonatal disease results from RDS or its complications
30
The lungs are under inflated and the alveoli contain amorphous material (hyaline membrane) from substances int he circulation and the injured pulmonary epithelium in __
RDS
Treatment for RDS
Supplementary oxygen and artificial surfactant -more than 90% of neonates with RDS survive
Fresh healthy lungs always contain some air. Pulmonary tissue floats. In contract a diseased lung may __
Sink
Do lungs of stillborn sink or float
Sink
Congenital diaphragmatic hernia
Lungs may not envelop normally
Why have lung hypoplasia with congenital diaphragmatic hernia
Changes in growth factors that exist before the abdominal viscera becomes abnormally positioned.
Characterization of lung hypoplasia
Markedly reduced lung volume .
Why di infants with congenital diaphragmanetic hernia die
Pulmonary insuffiency, despite optimal prenatal care, because their lungs are too hypoplastic to support extrauterine life
