HE 20 Respiratory II Flashcards
What are type 1 pneumocytes?
Squamous cells in the alveoli Very thin Line majority of the alveolar lumen Joined to each other by tight junctions Non-mitotic
What makes up the interalveolar septum (blood-air-barrier)?
Type I alveolar cells
Type I capillary endothelium
Fused basal lamina between the two
These are the layers that O2 must pass through to get to the blood.
What is ARDS and it causes?
Adult Respiratory Distress Syndrome
Inhaled toxic fumes or hot vapors damage alveoli or bacteria in the blood from sepsis damages the endothelial cell.
Either way, the septum is damaged and fluid can leak out of the vessels into the alveolar lumen. A hyaline membrane also builds up over the damaged area.
Causes acute respiratory failure.
What are septal cells?
Type II alveolar cells Cuboidal Stem cells of the alveoli Secrete surfactant Located at the junctions of alveoli Help with anti-bacterial-viral-fungal Involved in inflammatory response
What are dust cells?
In the alveolus
Originate from monocytes
Phagocytosis: irritants, particulate, microorganisms, surfactant
Antigen presentation
What ensures patency in the alveoli?
Structural from elastic fibers
Chemical from surfactant
What epithelial cells are present in the respiratory branches of the lungs and not in the other parts?
Squamous epithelium.
The simple squamous cells are the type 1 alveolar cells that line the alveoli and allow for gas exchange to occur.
What is the last branch to have all cuboidal epithelial cells?
Terminal bronchiole because it is the smallest branch that does not participate in gas exchange.
What are the three types of cells that serve as stem cells in the respiratory tract?
Basal Cells down to the bronchi
Clara cells in bronchioles (including resp. bronchioles)
Type II alveolar cells in the respiratory structures including resp. bronchioles
What is the last structure to have cuboidal cells?
respiratory bronchioles
What is the only structural difference between alveolar duct and sac?
The duct has slips of smooth muscle and the alveolar sacs do not have smooth muscle.
Epidermis comes from which germ layer?
Surface ectoderm
The CNS and PNS come from what embryonic germ layers?
CNS from neural tube
PNS from neural crest
What germ layers for the epithelium of the GI tract and respiratory systems?
Endoderm
What does intermediate mesoderm become?
Urinary and reproductive systems
What germ layer gives rise to the dermis?
Dermatome which comes from mesoderm
What germ layer produces the axial skeleton?
Sclerotome from paraxial mesoderm (somites)
Where does skeletal muscle come from?
Myotome
What germ layer forms the bones, cartilage and general CT of the body wall and limbs?
parietal mesoderm from the lateral plate
What does visceral mesoderm become?
cardiac, smooth muscle, general CT (organs), circulatory system
What is the most common complication during the formation of the lungs (respiratory diverticulum) from the gut tube early in embryonic development?
Superior portion of esophagus separates from trachea but the inferior portion does not. This creates esophageal atresia (a blind esophagus superiorly) and tracheoesophageal fistula where the inferior portion of the esophagus is attached to the trachea.
What are the symptoms or signs in a baby of esophageal atresia with tracheoesophageal fistula?
Polyhydramnios prenatally because baby can’t swallow
Can’t drink milk postnatally
Stomach juices in the lungs
By what gestational age have the secondary and tertiary bronchi formed?
By week 8
By week 16, what respiratory structures have formed and what is the name of this period?
Trachea down to the terminal bronchioles. No respiratory portions have formed quite yet. Called the pseudoglandular period.
