Pulmonary Histology Flashcards by Megan Howell

Where is air filtered?

Nasal Cavities

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What 4 things comprise the air conduction system?

Pharynx
Larynx
Trachea
Bronchial Tree

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What is responsible for your sense of smell?

Olfactory mucosa

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What does each nasal cavity open external to? Internal with?

External - with a nostril

Internal - with a choana

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What is the most anterior portion of the nasal cavity? What type of epithelium is it lined with?

Vestibule

Stratified squamous

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What is found on the epithelium of the vestibule? What is their purpose? What is associated with these structures?

Vibrissae - stiff hairs
Trap larger dust particles
Sebaceous glands

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What segment occupies most of the volume of the nasal cavity? What 4 things constitute its function?

Respiratory segment

Warm, moisten, filter, and inspire air

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What two layers compose the lining of the respiratory segment?

Ciliated pseudostratified columnar epithelium

Lamina propria

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What 5 cells types compose the ciliated pseudo-stratified columnar epithelium? Are they found throughout the conducting part of the respiratory system?

Ciliated Cells
Goblet Cells
Basal Cells
Brush Cells
Small granule Cells
Yes

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What is the purpose of ciliated cells?

Move mucous towards to larynx

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What type of secretion do goblet cells utilize?

Merocrine

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What is formed by ciliated cells and goblet cells? What is its function?

Mucociliary apparatus

Trapping and removing small particles from the respiratory system

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Where are basal cells found in the epithelium? What is their purpose?

Near base/lamina propria

Replacement cells

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What cover brush cells? What is their purpose? Absorption?

Short blunt non-motile microvilli

Receptor cells, NOT for absorption

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What cells are small granule cells homologous to from the GI tract?

Enteroendocrine cells

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What two things can the lamina propria of the respiratory tract be attached to?

Perichondrium or periostium

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What does the lamina propria contain to help warm the inspired air? Between what two conchae is this most prominent? What happens during an allergic reaction?

Extensive venous plexus
Middle and inferior conchae
This may become engorged and obstruct airflow

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What are the two main functions of turbinates?

Increase surface area for warming/moistening air

Cause air turbulence

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How does the lamina propria of the olfactory segment differ from that of the respiratory segment?

Thick lamina propria in olfactory segment

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What type of cell does the olfactory epithelium contain that the respiratory system does not? What cell type does it lack?

Contains neurons

Lacks goblet cells

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Where does the nulcei of supporting cells, olfactory cells, and basal cells lie in the epithelium of the olfactory segment?

Supporting cells - nuclei are apical
Olfactory cells - nuclei are in middle
Basal cells - nuclei are near base (lamina propria)

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What type of cell is an olfactory cell? Where is it found in the epithelium?

Neuron

Spans entire thickness of epithelium

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What do the dendrites of olfactory cells form as they profect toward the apical pole of the cell? What is this covered with?

Olfactory vesicle - a knob like structure

Covered with immotile cilia

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What type of receptor is contained within the plasma membrane of the cilia of the olfactory vesicle? What family does it belong to?

Olfactory receptor

Belongs to G protein-coupled receptors

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What do axons of olfactory cells form?

Olfactory nerve

What is the most numerous cell type in the olfactory epithelium?

Sustentacular (supporting) cell

What two roles do sustentacular cells provide to olfactory cells?

Mechanical - support | Metabolic - produces odorant-binding proteins

What is one major unique characteristics of olfactory neurons?

Can be replaced in postnatal development

What three things compose the lamina propria of the olfactory epithelium?

Bowman's glands Unmyelinated axons Venous sinuses

What type of glands are Bowman's glands of the olfacory mucosa?

Branched tubuloalveolar serous-secreting glands

What lines the nasopharynx?

Respiratory epithelium

What is most of the larynx lined with? What does it change to in areas of high abrasion?

Ciliated pseudostratified columnar | High abrasion areas - stratified squamous

What is the flexible tube that connects the larynx to the bronchi?

Trachea

What are the 4 layers of the trachea?

Mucosa Submucosa Cartilage Adventitia

What two things compose the mucosa of the trachea?

Ciliated pseudostratified columnar epithelium | Lamina propria

What is the main component of the well developed reticular lamina of respiratory epithelium in the trachea?

Collagen

What is the boundary between the mucosa and submucosa of the trachea?

Elastic membrane

What separated the submucosa of the trachea from the adentitia?

Tracheal cartilage

What is connected to the free ends of the tracheal rings?

Trachealis muscle

Where do the submucosal glands in the trachea extend to? What do they secrete?

Extend through lamina propria and open on surface of epithelium Secrete mostly glycoproteins

Is the tracealis muscle continuous? What type of muscle is it?

No | Smooth muscle

What are two distinct characteristics of bronchi?

Cartilaginous plates | Continuous layer of smooth muscle

What are the 5 layers of the wall of a bronchi?

``` Mucosa Muscularis Submucosa Discontinuous cartilaginous plates Adventitia ```

Besides ciliated pseudostratified columnar epithelium with goblet cells over the lamina propria, what is found within the lamina propria of bronchi that is not typically found in the trachea?

BALT - bronchi-associated lymphatic tissue

What type of muscle is the muscularis?

Smooth

What two things compose the submucosa loose CT of the bronchi?

Glands and adipose tissue

What disappears as bronchi's descend that makes them turn into bronchioles?

Discontinuous cartilaginous plates disappear

How big are bronchioles?

1mm or less

What two things to bronchioles not contain?

Cartilage and glands

What separated bronchioles?

Pulmonary septa - thin layer of connective tissue

What line terminal bronchioles? What two types of cells are found here? Purpose of each?

Simple cuboidal epithelium (ciliated) Cuboidal with cilia - transport of secretions upward Club cells - specialized secretory cells - secreting lipoproteins (surface-active agents) and club cell proteins - abundant component of airway secretions

Is there a significant amount of smooth muscle in walls of terminal bronchioles?

Yes

What is the first segment to perform gas exchange?

Respiratory bronchioles

What type of cell composes a majority of the lining of respiratory bronchioles?

Club cells

Is there a significant amount of smooth muscle in the walls of respirtory bronchioles?

What does the respiratory bronchiole become when more and more alveoli open up into it?

Alveolar duct

What are spaces surrounded by clusters of alveoli called?

Alveolar sacs

How larg is the inner surface of human lungs?

75 m^2

What separateds alveoli from eachother?

Alveolar septa

What do the capillaries and the connective tissue of the septum form?

Interstitium

Where is the richest capillary network in the body found?

Interstitium of alveoli

Are the walls of capillaries surround alveoli continuous or fenestrated?

Continuous

What are the two main types of cell that line the air spaces of the alveolus?

Type I pneumocyte | Type II pneumocyte

Which pneumocyte is regenerated from the other? Discuss similarities and differences

Type I pneumocyte - flattened squamous cell, 95% surface, only 1/2 of the cells on the surface, joined by occluding junctions, basal lamina fused with tight capillaries. Regenerated from Type II Type II pneumoctye - large secretory cell, contains mulilamellar bodies contianing surfactant, constitute 1/2 of cells on alveolar surface

What three things compose the barrier that most gas exchange occurs across?

Type I pneumocyte Endothelial cells Fused basal laminae

How are granules of surfactant released?

Exocytosis

Where are Type II pneumocytes more concentrated?

Around septal junctions

What is RDS (respiratory distress syndrome)?

Insufficient synthesis of surfactant by Type II pneumocytes

What are found within the interalveolar septum that connects neighboring alveoli? What is their function?

Alveolar pores - equalize air pressure and provide collateral air circulation if bronchi are obstructed

What are alveolar macrophages derived from? What two areas are they found? What is their purpose?

Blood monocytes Septal walls and alveolar spaces Collect particles such as dust and pollen

What is the most common lung cancer and can be found in both smokers and non-smokers?

Non-small-cell carcinoma | Two types - squamous cell carcinoma and adenocarcinoma

What are the most aggressive and rapidly growing lung cancer?

Small cell carcinomas (Oat cell carcinomas)