Flashcards in Histology Pulm Deck (51):
The ____ is the most anterior part of the nasal cavity and its lining is the continuation of the skin of the face, which is ____ epithelium. The epithelium contains ___ used to trap dust particles.
The ___ segment of the nasal cavity occupies most of the volume of the nasal cavity. The lining consists of 2 layers. Describe them.
1. Ciliated pseudostratified columnar epithelium with goblet cells faces the lumen. Contains 5 cell types
2. Underlying lamina propria attached to periosteum or perichondrium. Contains venous plexus of inferior and medial nasal conchae (allergic rxns when these vessels are engorged)
What are the 5 cell types in the Ciliated pseudostratified columnar epithelium of the respiratory segment of the nasal cavity?
1. Ciliated cells: tall columnar cells. Numerous in conducting parts. Move mucous.
2. Goblet cells: mucous secretion.
3. Basal cells: differentiate into other cells
4. Brush cells: receptor cells that have short blunt microvilli.
5. Small granule cells: homologous to enteroendocrine cells of the GI tract
What two cell types form the mucociliary apparatus?
Respiratory segment of the nasal cavity:
Medial wall vs. lateral wall
Lateral: forms folds called turbinates or conchae
What is the function of nasal turbinates/conchae?
Increase surface area for warming and moistening of incoming air
-also cause air turbulence which allows for conditioning of air
How is olfactory epithelium different from the rest of the respiratory epithelium?
It contains neurons and lacks goblet cells
What kinds of cells does the olfactory epithelium contain?
1. Olfactory cell
2. Basal cell
3. Supporting/sustentacular cell
Describe supporting/sustentacular cells of olfactory epithelium
tall columnar cells
apical nuclei, covered with microvilli
mechanical and metabolic support for olfactory cells through production of odorant-binding proteins
Describe olfactory cells
spans entire thickness of epithelium
Describe basal cells of the olfactory epithelium
____ cells are among the very few neurons in our body that are actively replaced in the postnatal development.
The ___ of the olfactory epithelium is unusually thick and contains the following 3 structures:
1. Bowmans glands
2. Unmyelinated axons
Describe Bowmans glands
Branched tubuloalveolar serous secreting glands
Trap odiferous substances
Washing of surfaces so new smells can be detected
Most of the larynx is lined with ___ epithelium that changes to ___ epithelium in the areas of high abrasion (i.e. Epiglottis, vocal cords, etc.)
Ciliated pseudostratified columnar
The trachea connects the ___ to the ____.
The larynx connects the ___ to the ___
1. Larynx to bronchi
2. Pharynx to trachea
The mucosa of the trachea is composed of ____ epithelium and ___
Ciliated pseudostratified columnar epithelium and lamina propria
Respiratory epithelium is ____
Ciliated pseudostratified columnar epithelium
In smokers, the basement membrane becomes ___ due to constant irritation of the mucosa.
What are the cell types found in the epithelium of the trachea?
1. Ciliated cells
2. Goblet cells
3. Brush cells
4. Small granule cells
5. Basal cells
The boundary between the mucosa and submucosa of the trachea is defined by ___
An elastic membrane
Describe the submucosa of the trachea
Seromucous glands whose ducts extend through the lamina propria and open on the surface of the epithelium where secretory products (mostly glycoproteins) are distributed along the surface
The submucosa of the trachea is separated from its adventitia by ___, which are ___ shaped and connected to the ___ muscle (which is composed of smooth muscle fibers). This muscle layer is not continuous and is only found on the ___ side of the trachea.
The ___ layer of the trachea contains larger blood and lymphatics vessels and nerves
Bronchi are characterized by the presence of ___ and a continuous layer of ____
Try or false:
Bronchi epithelium and trachea epithelium are identical
____ formed by hyaline cartilage covered with perichondrium descend into minor bronchi. When these disappear, the air tubule is designated as a bronchiole.
Discontinuous cartilaginous plates.
Adventitia of bronchi is composed of dense CT that is adjacent to that of ___
Pulmonary a. and lung parenchyma
Bronchioles are usually ___ in diameter
1 mm or less
True or false:
Walls of bronchioles contain cartilage and glands
Branching pattern of larger bronchioles:
Larger bronchioles - terminal bronchioles - respiratory bronchioles - alveoli
___ bronchioles supply pulmonary acini
Terminal bronchioles are lined with ___ epithelium that is formed by 2 cell types ____
1. Cuboidal or low columnar cells with cilia (assist in transport of secretions up the bronchioles. Outnumber other types of cells)
2. Club cells (specialized secretory cells in apical portion, lipo-proteins and club cell proteins)
As the respiratory bronchioles proceed distally what happens?
More and more alveoli open into the bronchioles until there is nothing left of the wall
This becomes the alveolar duct
Spaces surrounded by clusters of alveoli are called ___
___ represent the major site of gas exchange. Presence of these increase the internal surface area of the lung, which in a human is close to ____ meters squared
The capillaries and connective tissue of the alveolar septum constitute the ___, within which is found the richest ____ in the body
The walls of the capillaries in the alveolar septa are ___ and lined with____
Continuous (NOT fenestrated)
Very thin endothelial cells
The air spaces of the alveolus are lined with 2 main cell types:
1. Type I Pneumocyte
2. Type II Pneumocyte
Describe the Type I Pneumocyte
-95% of alveolus surface
-joined to each other by occluding junctions
-not capable of mitosis
-basal laminae are fused with endothelial cells of tight capillaries bound by occluding junctions
What cells represent the air-blood barrier? Gas exchange occurs primarily here
Type I Pneumocyte
Fused basal laminae
Describe the Type II Pneumocyte
AKA septal cell or type II alveolar cell
-large, rounded, cuboidal
-progenitors for type I Pneumocyte
-more concentrated in septal junctions
-capable of mitosis
What are multilamellar bodies?
Contain surfactant which is released by exocytosis to reduce surface tension and prevent collapse of alveoli
In premature infants the levels of surfactant synthesis may be insufficient.
Alveoli may collapse
What is this called?
Respiratory distress syndrome (RDS)
How do you reduce the risk of RDS in premature infants?
Give exogenous surfactant at birth
What do alveolar pores do?
Located in interalveolar septa
Connect neighboring alveoli
Equalize air pressure
Provide collateral air circulation of bronchioles is obstructed
Alveolar macrophages are derived from ___. They are present inside the ____ and ____
Septal walls and alveolar spaces
More than _____% of deaths worldwide are due to cigarette smoking.
The 2 most common types of malignant tumors found in the lungs are ____ and ____
____ is the most common lung cancer (75 %
of all malignant tumors of the lung), which is a fast-developing, usually metastasizing tumor. This type of lung cancer occurs in both smokers and non-smokers. The two most common types are ___ and ___
Squamous cell carcinoma