2. Airway Histology Flashcards
General Outline of the Respiratory System
• Two main portions: • Air-conducting - Passage for inhaled and exhaled air in and out of the respiratory system: • \_\_\_\_. • Nasopharynx and oropharynx. • \_\_\_\_ • Trachea, bronchi and bronchioles.
- Respiratory – Exchange of gases between air and blood:
- ____
- Alveolar ducts and sacs.
- ____• Air-conducting
○ Starts at nasal cavities, and ends in the lungs at the level of the ____
• Respiratory
○ Only at this level is where there is ____ between the alveoli and blood
○ Respiratory bronchioles are different from conducting bronchioles
nasal cavities larynx respiratory bronchioles alveoli bronchioles gas exchange
Nasal Cavity: Respiratory and Olfactory Epithelia
• Respiratory area: • \_\_\_\_ with goblet cells. • Lamina propria: • \_\_\_\_ with seromucous glands. • Continuous with \_\_\_\_ or perichondrium, forming the \_\_\_\_ of the nasal cavities.
- Olfactory portion:
- Olfactory epithelium:
- ____ cells.
- ____ olfactory neurons.
- ____ olfactory neurons.
- Supporting or ____ cells.
- ____ glands.• Two types of epithelia in each portion are very different
• Respiratory area
○ Involved in transport of air in and out
○ Pseudostratified ciliated epithelium
○ Underneath you have CT, that is continuous with the bones and cartilage
• Olfactory portion
○ Epithelium that contains ____ cells (supporting/sustentacular cells)
○ Mainly based on an epi very rich in neurons
pseudostratified ciliated epithelium
connective tissue (CT)
periosteum
wall
basal immature mature sustentacular olfactory
ciliated columnar
Nasal Cavity: Respiratory and Olfactory Epithelia
• Respiratory epithelium ○ \_\_\_\_ and it is \_\_\_\_ ○ Bones are in close proximity • Olfactory epithelium ○ Much wider ○ \_\_\_\_ ○ Rich in neurons
columnar epithelium
pseudostratified
pseudostratified epithelium
Nasal Cavity: Respiratory Epithelium
• \_\_\_\_ produce mucus ○ Secretory cells ○ Glands made by a \_\_\_\_ cell that produces mucus • In the sub-mucosa ○ Presence of glands § \_\_\_\_ glands § \_\_\_\_ glands □ Secretion in \_\_\_\_ proteins, other proteins
goblet cells single mucus serous defense
Nasal Cavity: Olfactory Epithelium
• Olfactory epithelium: Basal cells: • Mitotically \_\_\_\_. • Progenitors of \_\_\_\_. Immature olfactory neurons. Mature olfactory neurons: • \_\_\_\_ neurons. • Apical surface: \_\_\_\_. • Basal region: \_\_\_\_. Supporting cells: • \_\_\_\_ epithelium.
Olfactory glands of Bowman:
• ____.
• Secretion of serous fluid: ____
• ***
• Olfactory epithelium
○ Rich in neurons
○ Supporting cells (sustentacular)
§ Pseudostratified ciliated columnar epi
§ In the epi, there is a high abundance of neurons
□ Present in different ____
□ Neurons that are more immature, and some that are more mature
□ The mature neuron reaches the ____ of the nasal cavity, with a modified cilia where the signal transduction after binding an odorant is located
○ R: at bottom is ending of neurons, and if looking in more detail, the nuclei of the ____ is more ____ than the nuclei of the neurons which is more basal
○ Immature cells do not reach the ____
○ Presence of secretory glands: olfactory glands of Bowman
§ Create the OBP, which is involved with the ____ of sense of smell
active olfactory neurons bipolar knob-like dendrite axon pseudostratified ciliated columnar
subepithelial
odorant-binding protein (OBP)
populations
lumen
supporting cells
apical
neuron
transduction
Nasal cavity: olfactory epithelium
• Cilia from both sustentacular cells and neurons • Wider bands of the nuclei are from the \_\_\_\_ • Under the epi is the submucosa: \_\_\_\_ ○ Some have ducts that liberates OBPs into the cavity
neurons
glands of bowman
Larynx
- Wall of the larynx:
- ____ cartilage.
- ____ core of the epiglottis.
• Epithelia:
• ____ epithelium:
____ surface and a small extension of the pharyngeal surface of ____ and ____.
• ____ epithelium with goblet cells: elsewhere.
- Submucosa:
- CT, continuous with that of ____.
- Laryngeal seromucous glands (except at the ____).
- Lamina propria:
- Loose CT, rich in ____.
thyroid and cricoid hyaline
elastic cartilage
stratified non-keratinizing squamous
lingual
epiglottis
true vocal cords
pseudostratified ciliated
pharynx and trachea
true vocal cords
mast cells
Larynx: Epiglottis
• Higher magnification of the epiglottis • On the lingual side: ○ The epithelium is very \_\_\_\_ ○ \_\_\_\_ epi § \_\_\_\_ § Similar in oral mucosa, and upper 1/3 of the \_\_\_\_ § Goes all the way to the \_\_\_\_ surface • Type of epi then changes from stratified to the \_\_\_\_ squamous epi (the standard) • One feature that is associated with the pharyngeal down to trachea ○ \_\_\_\_in the submucosa
thick stratified squamous non-keratinized epiglottis pharyngeal
pseudostratified ciliated
seromucus glands
Larynx: true and false vocal cords
• Once reach false vocal cords > find \_\_\_\_ epithelium ○ See the presence of the \_\_\_\_ glands • When reach level of true vocal cords > changes from pseudostrat to \_\_\_\_ epithelium which is \_\_\_\_ ○ Switches because the vocal cords are subject to mechanical \_\_\_\_ and erosion, and a way to protect the underlying ligament is to isolate it with abundant layers of cells that are rich in keratin ○ Non-keratinizing in the sense in the extreme richness of dead cells on skin; but this epi is still much richer than the pseudostratified ciliated (which is much more fragile) • When reach the subglottis > the tissue changes back to the \_\_\_\_ columnar ○ Have the \_\_\_\_ all the way down
pseudostartified ciliated seromucous stratified squamous non-keratinizing stress pseudostratified ciliated columnar seromucous glands
Summary of the histology of the conducting and respiratory airways
• Reaching the actual pulmonary tree below the larynx that are involved in movement of air in and out of lungs, and exchange of gases inside the lung • The tree is divided into: ○ Conducting (from \_\_\_\_) ○ Respiratory (starts at \_\_\_\_) • In trachea, have the \_\_\_\_ epi with goblet cells • At one point, lose the \_\_\_\_, and the cells become less columnar and more \_\_\_\_ until you have a \_\_\_\_ epi, and then a \_\_\_\_ • Presence of ciliated cells ○ Goes all the way to the junction between the \_\_\_\_ parts • Presence of smooth muscle and presence of elastic fibers ○ Presence of both for the entire \_\_\_\_ ○ Smooth muscle regulated by hormones + autonomic system ○ Looking at abundance of SMC down to the alveoli § These cells are regulated in term of contraction and dilation by hormones, and mostly by the \_\_\_\_ § Also important in pathological situations: asthma
trachea to terminal bronchioles resp bronchioles to alveoli pseudostratified ciliated goblet cells cuboidal simple cuboidal SS conducting and respiratory tree ANS
Cells of conducting airways
• Major types (by abundance): •
Ciliated cells: • Clearing of \_\_\_\_ Club cells: • Secretion of \_\_\_\_ Goblet cells: • Secretion of \_\_\_\_.
• Minor types (by abundance): Tuft cells: • I\_\_\_\_ sensors. Neuroendocrine cells: • \_\_\_\_ sensors, signaling to other lung cells and CNS. Ionocytes: • Maintenance of \_\_\_\_ (?). • High expression of \_\_\_\_ Regulator Cl- channel. Basal cells: • \_\_\_\_ cells.
• GOBLET CELLS ARE MAJOR TYPES AND NOT MINOR TYPES • Not all cells are present in the same section at the same time • Grouping is based by \_\_\_\_ • Major types: ○ Where you find goblet cells you usually don't find \_\_\_\_ cells; distinguishes one section of the tree from another • Minor types: ○ (tuft) § Cells involved in immune defense that serve as sensors when pulm tissues are invaded by pathogen ○ NE cells § Also found in the \_\_\_\_ § Serves as a mechanical, gas and signals to other cells and the CNS ○ Ionocytes § Target for cystic fibrosis; involved with the [???] of Cl- • Memorize the three major types for the exam
mucus and debris
mucus components
mucus proteins
immune (infection) oxygen and stretch ion concentration cystic fibrosis transmembrane conductance stem and progenitor
abundance
club
GI tract
Conducting airways: Trachea
- Epithelium:
- ____ epithelium.
- Very ____ basal lamina.
- Cell types:
- ____ cells.
- ____ cells.
- ____ cells.
- Lamina propria:
- CT, rich in ____.
- Submucosa:
- ____ glands.
- Cartilage:
- Stack of ____ cartilages.
- Surrounded by ____.
- Adventitia:
- Mostly ____ tissue.• Lumen of the trachea is surrounded by hyaline cartilage forming a ring with the shape of the letter “C” > the ring is incomplete > posterior side of ring: ____(contraction/relax of the trachea)
○ This is characteristic of the trachea
• Look at the epithelium:
○ Subpops we saw before
○ Pseudostrat columnar ciliated epi
• In submucosa we will find secretory glands
pseudostratified columnar ciliated distinct ciliated goblet basal
elastic fibers
mucous and serous
C-shaped hyaline cartilages
adipose
trachealis muscle
Conducting airways: trachea
- ____ epithelial cell.
- ____ cell.
- ____ cell• L:
○ Each of three masses are sections of hyaline cartilage rings
○ Can see the seromucous glands in the submucosa
○ [???]
§ At this level both he basal lamina and lamina propia are really [???]
• R:
○ Ciliated epi cells
○ Goblet cells
○ Basal cells
§ Nuclei close to the ____
columnar ciliated
goblet
basal
basal lamina
Conducting airways: trachea
• L: ○ Position of trachealis muscle in relationship to the cartilage ○ High abundance of \_\_\_\_ glands § Producing mucus to export to the lumen • R: ○ Epithelium with ciliated cells, goblet cells ○ Apparent basal lamina ○ Lamina propia ○ Submucosa ○ \_\_\_\_ down below
seromucous
hyaline cartilage
Segmentation of the pulmonary tree
• At level of trachea • General rule: two things happen > the farther away you go from trachea into bronchi, with a higher branching order of the bronchi: ○ Diameter of the bronchi \_\_\_\_ ○ And the relative abundance of cartilage is also going \_\_\_\_ until it disappears completely • Why do trachea need cartilage, while the bronchioles do not? ○ Maintain an \_\_\_\_ airway ○ Huge volume of air at the trachea, if you have fluid moving, then the pressure decreases (venturi effect?); if not reinforced, they would \_\_\_\_ every time the air is inhaled or exhaled ○ At level of alveoli, the presence of \_\_\_\_ and smooth muscle maintain the airways open § The amount of fluid is much lower, traveling through these vessels § The tissues have enough \_\_\_\_ to resist the change in pressure
diminishes down open collapse elastic fibers and surfactant tensile strength
