McAuliffe Lung Histology Flashcards
Type I pneumocytes are:
- squamous cells in the alveoli walls through which gas exchange occurs.
- 95% of the surface area of the alveoli.
The connective tissue adjacent to the respiratory epithelium is called:
- lamina propria (tunica propria).
Loss of elastic tissue in bronchioles contributes to which disease?
emphysema.
Once odor molecules are dissolved by the serous fluid released by the Bowman’s Glands of the olfactory epithelium, what do the odor molecules do?
- trigger G-protein linked receptors on cilia.
- adenyl cyclase-cAMP pathway activated.
Function and structures of the respiratory portion of the respiratory system:
gas exchange
- Respiratory bronchioles, Alveolar ducts, alveolar sacs and alveoli.
What do alveolar dust cells (macrophages) phagocytose?
- microscopic foreign matter that escaped the mucous blanket in the conductive respiratory system.
Respiratory distress syndrome:
- Type II pneumocytes mature late in gestation.
- Premature infants may not produce sufficient surfactant for adequate respiratory function.
Walls of alveoli are composed of:
- Type I pneumocytes.
- Type II pneumocytes.
- Continuous capillaries.
What occurs to the alveoli and bronchioles in emphysema?
- small elastic fibers destroyed.
- bronchioles collapse.
- alveoli dilated.
What replaces the cartilage in bronchi as they become bronchioles?
- smooth muscle and elastic fibers
Cause of emphysema:
- elastic fibers in interstitial tissue are destroyed and air passages cannot remain open.
- gas movement into and out of alveoli compromised.
Function of lamellar bodies in Type II pneumocytes:
- discharge surfactant into alveolus lumen.
- reduces surface tension, prevents alveolar collapse (atelectasis), and increases elastic recoil during expiration.
Function of the serous secretion from Bowman’s glands in the lamina propria of olfactory mucosa:
dissolves odor molecules.
What type of cell are the arrows pointing to?
Type II pneumocytes with lamellar bodies
A pulmonary acinus is:
- the tissue served by one respiratory bronchiole.
- several respiratory bronchioles branch from each terminal bronchiole.
What is a swell body?
- the highly vascular tissue of the lamina propria in the nasal cavity that periodically engorges with blood to allow for mucosa rehydration.
Function of alpha-1-antitrypsin:
- protease inhibitor secreted by macrophages.
- limits action of elastases.
Emphysema is one of several types of:
Chronic Obstructive Pulmonary Disease (COPD).
What is BALT?
Bronchus Associated Lymphatic Tissue
- lymphoid tissue in the mucosa of the trachea and bronchus.
Olfactory receptor cells in the olfactory mucosa have ciliated dendritic processes that are bathed in a serous secretion from originating from:
- Bowman’s glands in the lamina propria.
Clara cells location and structure:
- Located in smallest bronchioles.
- Dome-shaped, non-ciliated cells.
Process of elastic fiber replacement in smallest bronchioles:
- elastases break down old elastic fibers.
- new fibers produced by fibroblasts in interstitial tissue.
- process mediated by alpha-1-antitrypsin.
Where are MALTs located?
lamina propria
Function of olfactory sustentacular cells:
- support and nourish the olfactory receptor cells.
What is a mucosa/mucous membrane?
- A wet epithelium kept moist by the secretions of glands.
Mucosal secretion in oral cavity:
saliva
The lamina propria of the nasal cavity is highly vascular and periodically becomes engorged with blood, obstructing the passage of air. What is the function of this?
periodic swelling allows the mucosa to rehydrate.
Function and location of mucociliary escalator:
- defense mechanism.
- pharynx to terminal bronchioles.
- as mucous reaches pharynx, it is swallowed or expectorated.
What separates the respiratory epithelium from the lamina propria?
- a basement membrane
Lymphocytes commonly found in the respiratory epithelium (intraepithelial lymphocytes) migrated there from the:
lamina propria.
Function of the adventitia of connective tissue layer of the trachea and bronchi:
- Contains cartilage that functions to keep the airway open.
- Contains smooth muscle that allows the diameter of the airways to be regulated.
Where are the mucous secreting glands of the respiratory system derived from?
- the respiratory epithelium
Characteristics of respiratory epithelium:
- Single layer pseudostratified epithelium.
- Goblet cells present.
- Basement membrane is very thick.
Does olfactory mucosa have goblet cells?
No.
Major characteristics of asthma (3):
- variable degree of airflow obstruction
- bronchial hyper-responsiveness
- airway inflammation
Function of small elastic fibers in the connective tissue of bronchioles:
- provide traction on the small airways to help keep them open during inspiration and expiration.
How does the maxillary sinus drain?
via ciliary action against gravity
What is MALT?
Mucosa Associated Lymphoid Tissue.
- May be a small a small group of lymphocytes, plasma cells and neutrophils or it may be as well developed as a lymphatic nodule.
A pulmonary lobule is:
- all tissue served by a terminal bronchiole.
- several respiratory bronchioles branch from each terminal bronchiole.
Function of olfactory basal cells:
- stem cells that proliferate to replace both the receptor cells and the sustentacular cells.
Type I pneumocytes are joined to each other via:
tight junctions.
Emphysema is characterized by:
- destruction of tissue distal to the terminal bronchioles.
DNES (diffuse neuroendocrine system cells / K cells) cells location and function:
- respiratory epithelium.
- secrete neuropeptides and vasoactive substances into the lamina propria.
Alveolar dust cells are:
- Alveolar macrophages.
- Travel between alveoli via alveolar pores.
Kartagener’s syndrome:
- inherited disorder.
- cilia lack dynein; non-functional.
- males sterile.
- males and females chronic sinusitis and bronchitis due to the inability to clear the respiratory passages.
Respiratory bronchioles are primarily lined by what cells?
clara cells
Effect of tobacco smoke on mucociliary escalator:
- increases mucous secretion
- poisons cilia of the mucociliary escalator
- respiratory infections more likely
Structures of the conducting system of the respiratory system:
- nose and nasal cavity
- nasopharynx
- pharynx
- larynx
- trachea
- primary, secondary and tertiary (segmental) bronchi
- 12-16 orders of subsegmental bronchi and non-respiratory bronchioles
Cell make-up of respiratory epithelium:
- ~30% goblet cells
- ~30% ciliated cells
- ~30% basal cells
Function of elastases:
- secreted by neutrophils.
- break down old elastic fibers in smallest bronchioles.
Type II pneumocytes structure and location:
- dome shaped cells in the alveolar wall
- contain lamellar or multilamellar bodies.
Layers of the trachea and bronchi:
- mucosa (contains BALT)
- submucosa
- adventitia of connective tissue containing hyaline cartilage and smooth muscle
Function of surfactant released by lamellar bodies in Type II pneumocytes:
- discharged into alveolus lumen.
- reduces surface tension (expiration)
- prevents alveolar collapse (expiration)
- increases elastic recoil (expiration)
- coats bacteria and viruses
Terminal bronchioles (the smallest bronchioles) are primarily lined by what cells?
clara cells (replace respiratory endothelium)
Mucosal secretion in respiratory system:
- mucous from goblet cells and other glands.
Mucosa structure in nasal cavity:
- Pseudostratified columnar epithelium with goblet cells and cilia (“respiratory epithelium”).
- Lamina propria is highly vascular.
Structures composing the blood-air barrier (3):
- type I pneumocyte.
- capillary endothelium.
- shared basement membrane between the two epithelia.
How does an environmental toxin such as tobacco smoke cause emphysema?
- tobacco smoke disrupts the normal function of macrophages by suppressing the production and/or function of alpha-1-antitrypsin.
- elastase overproduced; elastic fibers in smallest bronchioles destroyed.
The epithelium of the olfactory mucous membrane has three types of cells:
- olfactory receptor cells
- sustentacular/supporting cells
- basal cells
Composition of the lamina propria:
- relatively loose connective tissue with blood vessels, nerves, and lots of lymphatic vessels.
Function of the cilia of the respiratory epithelium:
- mucociliary escalator.
- moves the blanket of mucous (with trapped foreign material) proximally.
Changes to bronchiole respiratory epithelium as they get smaller:
- goblet cells no longer found.
- ciliated cells found more distally.
- epithelial cells become cuboidal.
Path from respiratory bronchioles to alveoli:
- respiratory bronchioles.
- alveolar ducts.
- alveolar sacs (lined with individual alveoli).
- alveoli have alveolar pores in their walls.
Clara cells location and function:
- Located in smallest bronchioles.
- Secrete a lipoprotein that reduces surface tension in airways to keep them open.
- Metabolize foreign materials.
- Stem cells to replace other bronchiolar epithelial cells.
Which bronchiole is the first to participate in gas exchange?
- respiratory bronchioles, which branch from terminal bronchioles.
- contain alveoli in walls.
Function of conducting system of the respiratory system:
warms, moistens and cleans the inspired air.
Function of basal cells in respiratory epithelium:
- stem cells that proliferate to replace ciliated cells and goblet cells.
