Pathophys Flashcards
Conducting portion of the respiratory tree
Nasal cavity Larynx Trachea Bronchi Bronchioles (terminal)
Respiratory portion
Respiratory bronchioles
Alveolar ducts
Alveoli
How is the R primary bronchi different from the L?
It is shorter, wider, and straighter.
What does primary bronchi divide into?
Lobar bronchi (5 total)
Define bronchopulmonary segment
Tertiary bronchi together with branch of pulmonary AA
What is the order of branching after tertiary bronchi?
Terminal bronchi - respiratory bronchi - alveoli - alveolar duct - alveolar sac
What body system is found in the area of the alveolar sac?
Lymphatics - removes debris from what you breathe in.
Which 3 tissue/cell types end at the terminal bronchioles?
- Goblet cells
- Glands
- Hyaline cartilage
Which tissue type spans the entire bronchial tree?
Epithelium
Where do ciliated cells end in the bronchiole tree?
Respiratory bronchioles
Which 2 tissues extend into the alveolar ducts and beyond?
Smooth muscle & elastic fibers
What are the 2 cells on the surface of the resp. epithelium and what are they coated with?
Ciliated cells + goblet cells, coated in mucus
Which cell does smoking harm?
Cilia - unable to beat properly, so they can’t move mucus properly.
Gland cell appearance
cuboid (vs. squamous appearance of blood vessels)
Define ventilation
refers to the movement and distribution of air within the conduction portion of the respiratory tract
Define diffusion
refers to the movement of O2 and CO2 between the alveolar space and the capillary blood
Define perfusion
refers to the flow and distribution of blood within the pulmonary vascular bed
Where does gas exchange occur?
In type I alveolar cells
Where is surfactant produced?
In type II alveolar cells
What is the job of the alveolar macrophage?
Live outside of the vascular space, when garbage enters the alveolus they can cross between type I alveolar cells, enter the alveolus itself, gobble up the garbage, then move back into the extravascular space where they’ll eventually wind up in the lymphatic channel and exit.
What structures make up the fused basal lamina?
The basement lamina of the vasculature and the basement lamina of the alveolar cells.
Where does the lung bud bifurcate?
At the carina.
How is negative pressure produced?
The parietal pleura absorbs oxygen from the pleural cavity, producing negative pressure within the cavity itself.
What week of gestation do type II alveolar cells appear?
Around 24 weeks.
What group of drugs slow/stop uterine contractions?
Tocolytics
What is surfactant?
“Soap” that lines the alveoli.
It has certain proteins and lipids that keep the surface tension such that the alveoli in the alveolar ducts, when you breath out, don’t collapse on themselves.
What produces respiratory distress syndrome (RDS)?
Absence of surfactant
What are the 4 roles of surfactant?
- To increasepulmonary compliance.
- To preventatelectasis(collapse of the lung) at the end of expiration
- To facilitate recruitment of collapsed airways
- Participates in immunity
What is hyaline membrane disease?
An older term for IRDS, based on the pathological findings at autopsy of premature infants.
The hyaline membranes were proteinaceous material in the damaged alveoli.
How is lung maturity determined in pregnancy?
In pregnancies >30 weeks – by amniocentesis
What 3 factors are measured for lung maturity?
- lecithin/sphingomyelin ratio (L/S ratio) – >2:1 ratio is desired
- phosphatidylglycerol (PG) – presence indicates maturity
- surfactant/albumin (S/A ratio) - < 35 indicates immaturity, 35-55 indeterminant, and >55 indicates maturity (correlates with L/S of 2.2 or greater)
What drug can hasten lung maturity?
An IM dose of steroids (commonly given to mothers under 38 weeks if contractions begin)
What are the 5 defense mechanisms of the respiratory system?
Vibrissae, mucous, bronchiolar secretions, lymph nodes, and alveolar macrophages.
What particles do vibrissae filter?
> 10μm filtered by vibrissae or trapped in the oropharynx
What particles are trapped in mucous and where?
< 10μm trapped in mucous in nasal cavity, trachea and bronchi swept by cilia
What characteristics of bronchiolar secretions allows them to participate in defense?
they have lysozyme and secretory IgA from lymphatic in connective tissues under the epithelia
How do lymph nodes participate in defense?
Lymph nodes surround bronchi at the lung hilum to filter lymph generated in acinus
What particles are “eaten” by alveolar macrophages?
1 - 5μm in size may be accessible to the terminal airways and alveoli where they are phagocytized by alveolar macrophages (same size as bacterium)