Respiratory Histology Flashcards
RESPIRATORY EPITHELIUM (TOLUIDINE BLUE)
- nuclei, ribosomes - dark blue, cytoplasm - blue
- ciliated cells
- non-ciliated goblet cells
- underlying tissue rich in blood vesseld (temp and humidity) and sero-muscous glands (secretions via ducts)
- mucous prevents dehydration of epithelium and traps particulate matter
SIMPLE/PSEUDO-STRATIFIED COLUMNAR CILIATED EPITHELIUM
with non-ciliated (basal/intermediate) stem cells - renewal of epithelium
@nose, nasopharynx, larynx, trachea, bronchi, bronchioles
NOSE (H&E AND ALCIAN BLUE)
- mucous/cartilage - blue
- central bone plate - pink
- respiratory epithelium either side
- thin walled blood vessels between epithelium and bone
- mucous containing goblet cells stained bright blue
NOSE OVERVIEW
- simple ciliated respiratory epithelium except at opening (hairy skin)
- concha covered in respiratory epithelium
- swell bodies - thin arterioles/venules deep to epithelium (nose bleeds)
- thin skin allows the escape of water (moistening air)
OLFACTORY EPITHELIUM
- @ roof of nose below cribriform plate
- pseudo-stratified columnar epithelium with basal and sustentacular (supporting cells)
- with bipolar neurons - dendritic process to surface (arrow)
- serous glands to surface (solvent for odorous substances)
- thicker than other respiratory epithelium
special cells = Bowman’s glands - small serous glands below olfactory epithelium
sustentacular cells tall, narrow, in contact w/ BM. bulky cytoplasm near lumen. cytoplasm accumulates yellow/brown pigment.
LARYNX
- respiratory epithelium, except vocal folds
- vocal folds - stratified squamous epithelium (more robust, may withstand vibration)
below epiglottis larynx -> 2 sets of folds
Vocal folds
- contain free upper margin of elastic tissue (conus elasticus)
- tensioned by voluntary skeletal muscle - vocalis muscle
FALSE FOLDS - upper - respiratory epithelium
TRUE FOLDS - lower - stratified squamous epithelium
VESTIBULE - between - respiratory epithelium
TRACHEA
- pseudo-stratified, ciliated, columnar epithelium
VOCAL CORDS
- stratified squamous epithelium
VOCAL FOLDS 2
- red arrow points to voluntary skeletal muscle
- green arrow points to sero-mucous glands
TRACEHA 2
- lumen of trachea = top
- C-shaped cartilage = bottom
- epithelium = pseudo-stratified columnar epithelium
- note serous glands visible which secrete to surface
- with H&E, goblet cells stain white
BRONCHUS (H&E)
- respiratory epithelium
- held open by hyaline cartilage framework (dark stain) which appear as isolated islands
- smooth muscle band under epithelium
- lymph nodules (MALT- mucosa associated lymph tissue) @ connective tissue
MALT NODULE (@ TRACHEA)
- left arrow points to MALT nodule
- right arrow points to smooth muscle band
LYMPH NODE = discrete, encapsulated collection of lymphoid tissue
MALT NODULE = no capsule, intimately related to epithelium
BRONCHIOLES
- simple ciliated respiratory epithelium
- no hyaline cartilage
- smooth muscle
- lymph nodules
- closely associated arteries and veins (branches of pulmonary artery/vein)
- no goblet cells
unlike bronchi may be contstricted by smooth muscle as no cartilage
TERMINAL/RESPIRATORY BRONCHIOLES (not respiratory epithelium)
terminal
- SIMPLE CUBOIDAL EPITHELIUM
- sparsely ciliated
- CLARA CELLS - many large ribosomes, ER, and granules -> function is secretory and synthetic
- sphincter-like smooth muscle ring
respiratory
- SIMPLE CUBOIDAL EPITHELIUM
- larger than terminal - beginning of respiratory portion of lung
this slide - terminal
ALVEOLI
- walls = capillaries between simple squamous epithelium
- fibroblasts in walls - produce type 3 collagen (reticulin) and elastic tissue (recoil)
- adjoining alveoli connected by pores = equal inflation
type 1 cells (thin) - flat cells, flat nuceli, 40% of population, 90% of SA
type 2 cells (globular) - secretes surfactant (lipid rich), 60% of pop., 10% SA, rounded, round dark staining nuclei
ALVEOLAR MACROPHAGES
- free roam in alveoli - phagocytose particulate matter and cell debris
- from monocytes in blood
- other macrophages stay in lung substance and engulf material that enters alveoli wall
- contain black ingested dust (carbon) particles
ALVEOLAR - enter teminal/respiratory bronchioles and pass to lymphatics or are transported by muco-ciliary escalator
FIXED/SEPTAL - remain in interstitium between cells and tissue
TYPE 2 PNEUMOCYTE
- A - alveolus
- BL - basal lamina (basement membrane)
- EP and EP1 - type 1 pneumocyte
- G - surfactant containing granules
PULMONARY BLOOD VESSELS
- large pulmonary blood vessels accompany bronchi
- indistinguishable from systemic counterparts EXCEPT large pulmonary arteries have longitudinally running elastic fibers in wall
- large pulmonary veins w/ clearly defined medial layeer of muscle and elastic tissue and well-defined internal elastic lamina
