Respiratory Histology Flashcards
Conduction portion of the RT
Collects and warms air.
Transmits air to respiratory portion.
Includes: nasal cavity, paranasal sinuses, nasopharynx, trachea, brochi and terminal bronchi.
Respiratory portion of the RT
Passes air to alveoli to assist in gas exchange.
Includes: respiratory bronchioles, alveolar ducts, alveolar sacs.
Respiratory epithelium
Pseudostratified columnar ciliated epithelium.
Includes a lamina propria which has a rich, vascular network w/ set of capillary loops.
Exist only in the airways.
Goblet cells
Secrete mucus via exocytosis.
Exist within the epithelium to trap foreign invaders.
Nasal cavities divided by nasal septum into 3 regions:
Nasal vestibule: inside of nostrils (lined by skin).
Respiratory region: inferior 2/3 of nasal cavities, lined with respiratory mucosa.
Olfactory region: upper 1/3 of cavity. Lined with olfactory mucosa.
Function of the nasal cavity
Adjust tempirature and humidity of inspired air. Enhanced by large surface area from turbinate bones.
Epithelium of nasal vestibule
Keratinized stratified squamous epithelium.
Epithelium of respiratory region of the nasal cavity
Pseudostratified columnar ciliated epithelium.
Olfactory mucosa
Has receptors for sense of smell.
Pseudostratified ciliated columnar epithelium.
Olfactory glands have serous secretions that dissolve odorant molecules.
**Hallmark: much thinner, lacks goblet cells.
Olfactory receptor cells
Have single dendritic process.
Have nonmotile cilia w/ odorant receptors that transmit signal to olfactory bulb.
Basal cells of olfactory mucosa
Stem cells for olfactory receptor and supporting cells.
Brush cells of olfactory mucosa
Ciliated, columnar epithelial cells.
Supporting/sustentacular cells of olfactory mucosa
Mechanical and metabolic support to olfactory receptor cells.
Trachea overview
Short and flexible conduit for air.
Extends from larynx and divides into main bronchi.
Lumen remains open due to cartilaginous rings.
Trachea has 4 layers which are:
Mucosa: ciliated pseudostratified epithelium and an elastic rich LP.
Submucosa: slightly denser CT than LP.
Cartilaginous layer: C-shaped hyaline cartilage.
Adevntitia: CT that binds trachea to adjacent structures.
Epithelium of terminal bronchioles
Simple cuboidal epithelium w/ clara cells.
Clara cells
Secrete lipoprotein substance that prevents luminal adhesion w/ airway collapse during exhalation.
Respiratory bronchioles
Simple cuboidal epithelium.
Elastic fibers.
Smooth muscle.
Branching of respiratory bronchiole
RB –> alveolar duct –> alveolar sac.
Alveoli overview
Lined with type I and type II pneumocytes.
Simple squamous epithelium.
Alveolar septum
Wall of alveolar capillaries surrounded by elastin and collagen fibers.
Alveolar pores
Small openings that permit movement of air between alveoli.
Type I pneumocytes
Line almost entirety of alveolar surface.
Creates surface for gas exchange.
In close association with capillaries.
Type II pneumocytes
Rounded cells comprising about 60% of epithelium, but cover 5% of surface area.
More numerous.
Secrete surfactant to prevent collapse.
Asthma
Chronic inflammation of airways.
Restriction of airflow due to inflammation and bronchospasm.
Infiltration of eosinophils, lymphocytes and MCs.
Thick bronchiolar epithelium w/ increased goblet cells, thick BM and hyperplastic smooth muscle cells.
Emphysema
Enlargement of airspaces distal to terminal bronchiole.
Destruction of alveolar walls.
Poor gas exchange.
Pneumonia
Inflammation of lung tissue.
Air spaces filled with WBCs, RBCs and fibrin.
Enlarged capillaries congested with RBCs.
Lung appears red due to increase in RBCs.
Visceral pleura
Covered in a flattened, mesothelium.
Underlying fibrous tissues of collagen and elastin fibers.
Extends into the lung as fibrous septa.
Has extensive lymphatic vessels.
