Cardiopulmonary 1 - Midterm; Anatomy & Embryology Flashcards
What embryonic tissue is the respiratory system derived from?
Endoderm (specifically - fore gut endoderm)
During which week of development does the tracheoesophageal folds fuse?
Week 5
The fusing of the tracheoesophageal folds during week 5 of development forms what structure?
Tracheoesophageal Septum
In the trachea, what embryologic tissue forms the epithelium, glands, and pulmonary epithelium?
Endoderm (specifically - fore gut endoderm)
What embryologic tissue gives rise to cartilage, connective tissue, and smooth muscle of the trachea?
Splanchnic Mesenchyme
Specifically - Splanchnic Layer of Lateral Plate Mesoderm
What defect causes abnormal passage between trachea and esophagus?
Tracheoesophageal Fistula
Which occurs in combination with Esophageal Atresia in 85% of cases
What is a “blind end esophagus” called?
Esophageal Atresia
During which week of development does the lung bud form?
Forms from endoderm during week 4.
During which week of development are primary bronchial buds formed?
Week 5
During which week of development are secondary bronchi formed?
Week 6
During which week of development are tertiary bronchi formed?
Week 7
During week 6 of development, how many secondary bronchi are formed on the right side?
3 (superior, middle, inferior)
During week 6 of development, how many secondary bronchi are formed on the left side?
2 (superior, inferior)
During week 7 of development, how many tertiary bronchi are formed on the right side?
10
During week 7 of development, how many tertiary bronchi are formed on the left side?
9
At completion of Bronchopulmonary segment branching at 24 weeks, how many orders of branching are there?
17 orders of branches, terminal bronchioles
At what week of development do the bronchopulmonary segments complete branching, thus completing formation of the conducting system of the lungs?
week 24
17 orders of branches, terminal bronchioles
What are the weeks of Pseudoglandular Stage of Lung Development?
5-17 weeks
What is formed during the Pseudoglandular Stage of Lung Development?
- terminal bronchioles formed - connective tissue - CANNOT survive if born - NO gas exchange possible
What weeks during lung development compose the Canalicular Stage?
16-25 weeks
What events occur during the Canalicular Stage of Lung Development?
- Vascularization
- Respiratory Bronchiole
formation
> formation of primordial
alveolar ducts - Terminal sacs formed
(primitive alveoli) - +/- survival of fetus if born
Which bronchioles does the terminal bronchioles develop into?
Respiratory Bronchioles (primordial alveolar ducts), which happens during the Canalicular Stage (16-25 weeks) of Lung Development.
What stage of lung development occurs from roughly 24 weeks until birth?
Terminal Sac Stage (or Saccular Stage)
What events take place during the terminal sac (saccular) stage of lung development?
- Gas Exchange
- Squamous Epithelium = Type I Pneumocytes
- Type II Pneumocytes (produce surfactant)
- infant will survive if born
What do terminal sacs from the terminal sac (saccular) stage of lung development give rise to?
Become Mature Aleoli
What pulmonary cell type is responsible for gas exchange?
type I pneumocytes
What type of epithelium are type I pneumocytes?
squamous epithelium
What type of epithelium are type II pneumocytes?
secretory epithelium
Which pulmonary cell type produces surfactant?
type II pneumocytes (secretory epithelium)
During what stage of lung development does surfactant production begin?
Terminal Sac (Saccular) Stage [24 weeks - birth]
What stage of lung development occurs from roughly 32 weeks - 8 years of age?
Alveolar Stage
What events occur during the Alveolar Stage of Lung Development?
- Alveolocapillary membrane formation
- Primitive Alveoli formation (which then form more primitive alveoli)
- Mature Alveoli formation
At what age does maturation of most alveoli occur?
3 years of age
What percentage of alveoli are mature at normal gestational birth?
5%
What clinical condition can be caused by too much surfactant in one area?
Tension Pneumothorax
What events are required for normal lung development?
1) fetal breathing movements (FMBs)
2) adequate thoracic space for growth
3) adequate amniotic fluid volume
Where and why does fetal breathing movements (FBMs) occur?
Occur in-utero with sufficient force to cause aspiration of amniotic fluid.
By way of which 3 mechanisms are intra-alveolar fluid cleared at birth of fetus?
1) through mouth & nose by pressure on fetal thorax during vaginal delivery
2) into pulmonary capillaries, arteries, and veins
3) into lymphatics
** steps 2 & 3 critical in C-section deliveries **
What does severe and chronic oligohydramnios cause?
- Retards lung development and may result in PULMONARY HYPOPLASIA.
Pulmonary Hypoplasia –> is at greater risk if oligohydramnios occurs prior to 26 weeks of gestation.
During which portion of lung development is risk of pulmonary hypoplasia significantly increased?
Oligohydramnios occurring prior to 26 weeks of gestation.
What is formed by the fusion of the 2 endocardial primordia?
Endocardium
What membrane separates the pericardial cavity from the pleural canals?
Pleuropericardial Folds (membrane)
Between which 2 membranes does the lungs develop?
Between Pleuropericardial Membrane and the Pleuroperitoneal Membrane.
From what embryonic tissue are the pleuropericardial folds derived?
Somatic Layer of Lateral Plate Mesoderm
From what embryonic tissue is the visceral pericardium derived?
Splanchnic Layer of Lateral Plate Mesoderm
From what embryonic tissue is the serous and fibrous pericardium derived from?
Somatic Layer of Lateral Plate Mesoderm
The Phrenic N. runs in what fold?
The Pleuropericardial Folds.
The pleuroperitoneal membranes migrate anteriorly to fuse with what?
Septum Transversum
What cavity is located inferior to the septum transversum and pleuroperitoneal membrane?
peritoneal cavity
What does the septum transversum become?
central tendon of the diaphragm
What gives rise to crura?
Dorsal Mesentery of Esophagus
List 5 signs/symptoms of respiratory distress syndrome?
- Tachypnea
- Nasal flaring
- Suprasternal, Interconstal, or Subcostal Retractions
- Grunting
- Cyanosis
What are 2 key finds on a chest X-ray in RDS patients?
- low lung volumes
- diffuse reticulogranular ground glass glass appearance
What causes RDS?
pt lacks sufficient surfactant production
** surfactant production occurs at 24 weeks during the saccular stage of lung development
List findings during physical examination of an infant with a congential diaphragmatic hernia.
- barrel-shaped chest
- scaphoid appearing abdomen
- absence of breath sounds on ipsilateral side
- if hernication on left side, heart beat is displaced to right due to mediastinal shift
What is the embryological cause of a congential diaphragmatic hernia?
Pleuralperitoneal folds (membrane) did not migrate & fuse with septum transversum correctly.
(**typically occurs on the left side)
What is the embryological cause of esophageal atresia and/or tracheoesophageal fistula?
Esophageal folds did not come together & fuse correctly to form the tracheoesophageal septum during week 5 of development.
During what week of development does the esophageal folds migrate and fuse to form the tracheoesophageal septum?
week 5
List a prenatal sign sign in 2/3 of tracheoesophageal fistula patients?
mother has polyhydramnios
List signs/symptoms seen in infant @ birth with tracheoesophageal fistula.
- coughing
- gagging
- cyanosis
- vomiting
- voluminous oral secretions
- possible respiratory distress
What is the cause of congenital lung cysts?
Though to result from disturbance in bronchial development during late fetal life.
What are the 2 terminal branches of the Internal Thoracic A.?
- Musculophrenic A. (lateral)
- Superior Epigastric A. (medial)
[continues inferiorly, deep to rectus abdominous m.]
What Artery gives off Anterior Intercostal As.?
Internal Thoracic A.
What artery arises from the Internal Thoracic A. around the 2nd rib?
Pericardiacophrenic A.
What artery does the Internal Thoracic A. arise from?
Subclavian A.
Does the Internal Thoracic A. course superficial or deep to the Transverse Thoracic Ms.?
Superficial
meaning, you would hit the internal thoracic a. and then the transverse thoracic ms.
From which artery does Medial Mammary A. arise?
Internal Thoracic A.
What are the 4 arterial branches coming off of the descending thoracic aorta?
- Unpaired Visceral Branches (visceral - go to viscera) > mediastinal A. > esophageal A. > pericardial A.
- Paired Lateral Visceral Branches
(visceral - go to viscera)
> bronchial A. - Paired Segmental Parietal Branches
(parietal - follow body wall)
> posterior intercostal a. - Superior Phrenic A.
What are the branches that arise from the posterior intercostal arteries?
- dorsal branch a.
- collateral branch a. (travel down & run along superior border of rib below)
- lateral cutaneous a. (travel through intercostal ms. and go to supply skin)
[**lateral cutaneous a. gives rise to Lateral Mammary Branch]
What are the 2 arterial sources that can give rise to a Lateral Mammary Branch?
- Lateral Mammary Branch (from Lateral Thoracic A.)
[**recall: lateral thoracic a. supplies the serratus anterior muscle] - Lateral Mammary Branch (from Lateral Cutaneous Branch of Posterior Intercostal A.)
What artery arises from the descending thoracic aorta just prior to passing through the aortic hiatus?
Superior Phrenic A.
List the 3 arteries that supply the superior portion of the diaphragm and the arteries that they arise from.
- Musculophrenic A. (from Internal Thoracic A.)
- Pericardiacophrenic A. (from Internal Thoracic A.)
- Superior Phrenic A. (from Descending Thoracic Aorta)
List the right arteries in order starting at the pulmonary trunk.
Pulmonary Trunk –> R. Pulmonary A. –> R. Superior Lobar A. (apical segment, posterior segment, anterior segment) –> R. Middle Lobar A. (lateral segment, medial segment) –> R. Inferior Lobar A. (superior segment, posterior basal segment, medial basal segment, anterior basal segment, lateral basal segment)
What vein runs with the posterior interventricular artery in the posterior interventricular groove?
Middle Cardiac V.
What vein runs with the anterior interventricular artery in the anterior interventricular groove?
Great Cardiac V.
What vein runs in the horizontal plane and passes just superficial to the right coronary artery?
Anterior Cardiac Vs.
What vein runs around the right side of the heart and empties into the coronary sinus along with the great cardiac and middle cardiac veins?
Small Cardiac V.
Which 2 arteries arise from the ascending aorta?
- Left Coronary A.
- Right Coronary A.
What are the branches off of the Right Coronary A.?
- Sinuatrial Nodal A.
- Conus Branch of Right Coronary A.
- Atrial Branch of Right Coronary A.
- Right Marginal A.
- Atrioventricular Nodal A.
What are the 2 terminal branches of the Right Coronary Artery?
- Right Posterolateral A.
- Posterior Interventricular A.
What are the branches of the Left Coronary A.?
- Circumflex Branch of the Left Coronary A. (or Circumflex A.)
- Anterior Interventricular Branch of the Left Coronary A. (or Anterior Interventricular A.)
- Left Marginal A. (arising from circumflex a.)
- Posterior Left Ventricular A. (arising from circumflex a.)
What arteries arise from the aortic arch?
- brachiocephalic trunk
- left common carotid a.
- subclavian a.
What vein runs with the right marginal a.?
Small Cardiac V.
Compare and contrast where the small cardiac v. and anterior cardiac v. empty?
- Small Cardiac V. –> coronary sinus
- Anterior Cardiac V. –> right atrium
In the course of the Great Cardiac V., what arteries does it run with depending on where it’s located?
- Great Cardiac V & Circumflex A.
- Great Cardiac V. & Anterior Interventricular A.
What artery runs in the right atrioventricular groove?
Right Coronary A.
Where does the azygous v. empty into?
Superior Vena Cava
What vein does the Right Posterior Intercostal Vs. always empty into?
Azygous V.
What veins do the Left Posterior Intercostal Vs. empty into?
- Hemiazygous V.
- Accessory Hemiazygous V.
** which come together and empty into the azygous v., and then into the superior vena cava **
What areas are lymphatics drained by the Thoracic Duct?
- lower extremities
- pelvis
- abdomen
- left half of thorax
- left upper extremity
- left side of head & neck superiorly
- subclavian lymphatic trunk & bronchomediastinal trunk in thorax
Where does the Thoracic Duct empty into?
Venous system near junction of Left Internal Jugular V. & Left Subclavian V.
List the 4 constriction points in which lodging typically occurs in the esophagus.
(listed superior to inferior)
1. Cricopharyngeus (muscle) Part of Inferior Pharyngeal Constrictor
- Arch of Aorta
- Left Main Bronchus
- Diaphragmatic Constriction (inferior esophageal “sphincter”)
True or False:
The Superior and Middle Cardiac Branches of the Vagus N. branch off once the Vagus N. is in the thorax.
False
Both branches arise from the Vagus N. in the neck.
True or False:
The Inferior Cardiac Branch of the Vagus N. branches off from from the Vagus N. in the neck.
False
Branches from Vagus N. when in the thorax.
Which Vagus N. (left or right) primarily contributes to the Anterior Vagal Trunk?
Left Vagus N.
Which Vagus N. (left or right) primarily contributes to the Posterior Vagal Trunk?
Right Vagus N.
What major artery does the Right Recurrent Laryngeal N. pass deep to on its way to innervate the larynx ?
Right Subclavian Artery
Which anterior rami fibers are carried by the Phrenic N.?
C3, C4, & C5
C3, 4, 5 keep the diaphragm alive
What muscle does the Phrenic N. course along on its way into the thorax?
Anterior Scalene M.
**recall: happening on both sides (bilateral)
Between what structures is the Phrenic N. sandwiched between as it courses through the thorax to the diaphragm?
> mediastinal parietal pleura
> fibrous pericardium
Which nerves is sandwiched between the mediastinal parietal pleura and fibrous pericardium in the thoracic cavity?
Phrenic N.
What 3 branches are given off of the Intercostal Ns.?
> collateral branch of intercostal N.
lateral cutaneous branch of intercostal N.
anterior cutaneous branch of intercostal N.
Which intercostal Ns. are the “Typical” Intercostal Nerves?
3-6 Intercostal Nerves
Which Intercostal Ns. are the “Atypical” Intercostal Nerves?
1-2 and 7-11 Intercostal Nerves