Structural Properties of the Lung Flashcards
What parts of the brain sense pH, [CO2] and [O2]?
Respiratory centers in the medulla
What is the major function of the upper airways?
Condition inspired air
What are the three things that the brain monitors?
pH
O2
CO2
Which two organs control the pH of the blood?
Lungs
Kidneys
Particles larger than what size and cleared from the upper airway?
10 micometers
Upper airway resistance (like the nose) is what percent? What affects this?
50%
Infections
What are the two components of the airway?
Conducting
Respiratory
What is the total surface area of the alveolar airway?
50 m^2
In which generations of airway branching are there no alveoli (known as the conducting zone)? Is there gas exchange?
1-16
No gas exchange
How many generations of airway branching are there?
23
Is there cartilage in the bronchi? Bronchioles? Alveoli?
yes for bronchi. No for lower down
Where does the mucus layer end in the airways?
Bronchioles
Where does the smooth muscle end in the airways?
alveoli
What is the main source of air resistance in the lower respiratory tract?
Bronchioles
What is the treatment for asthma?
Beta receptor agonists on smooth muscle of the bronchial endothelium
What is the main purpose of the alveolar compartment?
Gas exchange
What are the cells that are responsible for mucus production?
Goblet cells
What type of epithelium is present in the airway?
Pseudostratified ciliated
What is the purpose of the mucus blanket?
humidify air
Make airflow smoother
What is the function of the submucosal glands? Where are they present?
Produce mucous and serous secretions
Present where there is cartilage
What is the innervation of the submucosal and trachobronchial glands?
SANS
PANS–mostly
Local mediators
What are the cells types that clear the mucus in the upper respiratory tract? What do they produce?
Ciliated epithelial cells
Produce periciliary fluid (Cl secretion, Na absorption)
What is the purpose of the rhythmic ciliary beating?
Remove mucus
What is the MOA of CF?
Abnormal Cl secretion, leading to increased mucus thickness
What are the two key cells in the alveolar lumen? Which are the main structural component? Which produce surfactant?
Type 1 - form walls
Type 2 - surfactant production
What immune cells are present in the alveoli?
Macrophages
Mast cells
What comprises a respiratory unit?
Bronchiole
Alveolar ducts
Atria
Alveoli
What are the pores of Kohn? What is their purpose?
Connecting holes between alveoli that function as a means of collateral ventilation
What is the downside of pores of Kohn?
Allow for bacterial infections to spread easily
Each alveolus has how many capillaries?
500 (makes a sheet of blood flow)
What is the respiratory membrane?
The place where the gas exchange occurs- between endothelial cells of the capillaries
What is the composition of the respiratory membrane?
Surfactant Alveolar epithelium Epithelium BM Interstitial space Capillary BM Capillary endothelial membrane
What happens to the respiratory membrane in pnuemonia infections?
Increases the resistance to respiratory gas exchange
What is the cause of COPD?
respiratory membrane damage
Increases in hydrostatic pressure of the capillaries causes what? What causes this?
Increased flow out
Heart failure
What causes the SOB of heart failure?
Increased fluid present over the respiratory membrane
Where do antibodies in autoimmune diseases affect lung function?
In the capillaries at the respiratory membrane
What is the composition of the lung interstitium?
CT Smooth muscle Lymph Capillaries Cells
What are the cells in the lung interstitium that produce collagen and elastin?
Fibroblasts
What is the function of the elastin in the lung interstitium?
Elastin is the major contributor to elastic recoil of the lung
What is the function of the collagen in the lung interstitium
Collagen is the major structural component of the lung that limits lung
distensibility
What is the function of the parietal and visceral pleura?
Help provide expansion of the lungs
What is the function of the pleural fluid?
Sticks together
What is the source of the pleural fluid? Where does it go?
Comes from capillaries or the parietal pleura
Goes through parietal space and drains into lymphatic system
What are the areas that drain the pleural fluid?
Stomata
Which layer has stomata, the parietal or visceral pleura?
Parietal
In which layer are the microvessels closer to the pleural surface: the parietal or visceral pleura? What is the consequence of this?
Parietal
This means that the source of pleural fluid is from these capillaries
What can cause pleural effusion? How? (hint, capillaries pressures!) (2)
CHF
Causes increased pulmonary venous hydrostatic pressure from the VISCERAL side d/t increased left ventricular pressure.
Also decreased oncotic pressure in the blood
What causes atelectasis? (2)
Decreased pleural pressure (in the pleural space), leading to increased fluid uptake into the space
Blockage of lymph
What is the lungs role in the acid base balance?
Remove CO2
What is the lungs’ role in defense mechanism?
Remove the bacteria/viruses/
What is the lung’s role in metabolism?
Must match O2 demand
Does nasal resistance change with air flow? If so, how?
Yes, directly
What do the respiratory epithelial cells of the nasopharynx secrete to aid in defense?
Immunoglobulins
Interferons
Inflammatory mediators
What are the two major functions of the sinuses?
- Lighten the skull
2. Resonance for voice
How are the terminal bronchioles distinguished?
Smallest airways without alveoli
What are the three structures that comprise the last 7 generations of branching in the airway?
- respiratory bronchioles
- alveolar ducts
- alveolar sacs
What happens to the cartilage surrounding the bronchi as they enter the lungs?
Turn from C-shaped rings to plates
Do the bronchioles and alveolar ducts contain cartilage? What is the significance of this?
No, thus they are subject to collapse when compressed
As the cartilage plates become irregularly distributed around distal airways, what surrounds these airways? What is this intermingled with?
Muscle layer intermingled with elastic fibers
What are the three principle layers of tissue in the conducting airways?
- Inner mucosal surface
- Smooth muscle layer
- CT layer
What is the epithelial type in the bronchial wall?
Pseudostratified
What is the epithelial type in smaller bronchioles? Is cartilage present?
Simple, without cartilage
Where are submucosal tracheobronchial glands present?
Wherever there is cartilage in the tracheobronchial tree
What happens to the number of submucosal tracheobronchial glands present in chronic bronchitis?
Increase is size and number
What is the function of Clara cells? Where are these found?
Found at the level of the bronchioles
Unknown function
Where does airway resistance come from in the lower respiratory airway? How?
Bronchioles and bronchi through muscle contraction and secretions
True or false: the junctions between endothelial cells of the lungs are leaky
True- to allow for gas exchange
What are Kultschitzky cells?
neuroendocrine cells found in clumps throughout the tracheobronchial tree
and secrete biogenic amines, including dopamine, 5HT
What is the blood supply to the visceral pleura?
Bronchial circulation
What is the blood supply to the parietal pleura?
Intercostal arteries
What states can cause increased microvascular hydrostatic pressure? What is the result of this?
CHF
Increased pulmonary venous pressure moves fluid across the visceral mesothelium
What is the effect of a decreased microvascular oncotic pressure of the on the lungs?
A decrease in oncotic pressure in the
microvascular circulation will increase the tendency to form pleural interstitial liquid.
What is the effect of a decreased pressure in the pleural space of the on the lungs?
When there is a decrease in pressure in the pleural
space as in atelectasis, the pressure gradient from the pleural interstitium to the pleural
space increases and favors the formation of pleural liquid.
What can cause increased microvascular permeability in the lungs? Result?
inflammation of both pulmonary and
pleural microvessels
Liquid and protein leak across the lung and
pleural microvessels at an increased rate.
How can fluid from the peritoneum to the pleural space happen?
Through either diaphragmatic defects or diaphragmatic
lymphatics
What are the two ways in which the clearance rate of the pleural fluid decreases?
- Increase in venous pressure
2. Blockage of stomata
What are the two components of the conducting airways?
- Bronchi
2. Upper part of the bronchioles
What are the three components of the alveolar air spaces?
- Lower part of the bronchioles
- Alveolar ducts
- Alveolar sacs
The conducting airways are from what numbered airways?
1-16
What are the cholinergic receptors on the lungs?
M3