Respiratory Tract Flashcards
what is respiratory epithelium?
pseudostratified ciliated columnar epithelium with interspersed goblet cells
what are the functions of the nose?
- filtration
- humidification
- warming
- olfaction
what is the epithelia of the nose?
near opening:
- keratinising stratified squamous epithelium
further from opening:
- non-keratinising stratified squamous epithelium
- respiratory epithelium
what produces snot in the nose and where are they found?
seromucinous glands
- loose fibrous connective tissue beneath epithelia
what do the serous glands of Bowman secrete?
watery fluid (to wash surface of nasal cavity clean)
what is the epithelium of the roof of the nasal cavity?
respiratory (no goblet cells)
what are bipolar neurons and where are they found?
dendrite extends to surface to become club-shaped ciliated olfactory vesicle
- found in roof of nasal cavity
what are the functions of the nasopharynx?
- gas transport
- humidification
- warming
- olfaction
what is the nasopharynx lined by?
respiratory epithelium
what are the nasal sinuses?
air filled spaces within bones of skull and facial skeleton
what are the functions of the nasal sinuses?
- lower the weight of the skull
- add resonance to the voice
- humidify and warm inspired air
what are the nasal sinuses lined by?
respiratory epithelium
describe the structure of the epiglottis
elastic cartilage
what is the function of the larynx?
voice production
what is the larynx lined by?
respiratory epithelium (except vocal cords)
describe the structure of the larynx
- almost entirely hyaline cartilage
- seromucinous glands
what is the function of the hyaline cartilage in the larynx?
hold larynx open against negative pressure during inspiration
what are the vocal cords lined by?
stratified squamous epithelium
describe the structure of the vocal cords
- irregular fibrous connective tissue in Reinke’s space
- vocal ligament
- vocalis muscle
what lines the trachea?
respiratory epithelium
describe the structure of the trachea
- hyaline cartilage in C-shaped rings
- gap between rings filled by trachealis (vertical smooth muscle)
- submucosa
what do the bronchi and bronchioles have in common?
- smooth muscle
- some basal neuroendocrine cells
what are the differences in the structure of the bronchi and bronchioles?
bronchi: - partial cartilaginous rings - respiratory epithelium - seromucinous glands - goblet cells bronchioles: - ciliated columnar epithelium - few goblet cells - clara cells
what are the types of bronchi?
- main
- lobar
- segmental
describe the sequence of trachea, bronchi and bronchioles
- trachea
- main bronchi
- lobar bronchi
- segmental bronchi
- terminal bronchioles
- respiratory bronchioles
where are clara cells most commonly found?
terminal bronchioles
describe the structure of clara cells
- roughly cuboidal
- pale-staining vesicular cytoplasm
describe the structure of respiratory bronchioles
- spirally-arranged smooth muscle
- no cartilage
what type of epithelia lines the respiratory bronchioles?
cuboidal ciliated
what make up 40% of the cell population of the alveoli?
type 1 pneumocytes
what makes up 90% of the surface area of the alveoli?
type 1 pneumocytes
describe the structure of type 1 pneumocytes
- squamous epithelial cells
- flattened nucleus
- few organelles
how are type 1 pneumocytes adapted to their function?
very thin
what makes up 60% of the cell population of the alveoli?
type 2 pneumocytes
what makes up 5-10% of the surface area of the alveoli?
type 2 pneumocytes
describe the structure of type 2 pneumocytes
- round/cuboidal/columnar
- central round nucleus
- rich in mitochondria
- spherical bodies
which cells produce surfactant?
type 2 pneumocytes in alveoli
what are alveolar macrophages?
phagocytic cells derived from blood monocytes
what is the function of alveolar macrophages?
phagocytose bacteria and particulate matter that have reached the alveolar air spaces
how are alveolar macrophages removed from the lungs?
- lymphatics of lungs
- mucociliary escalator
where are alveolar macrophages found?
- interstitial connective tissue of alveolar walls
- lumen of alveoli
what is the blood-air barrier?
type 1 pneumocyte resting on basement membrane shared by vascular endothelial cell of an adjacent capillary
how many layers could you say there are in the blood-air barrier?
2, 3, 4 or 8
what is the interstitium?
loose fibrous connective tissue
- where endothelial cells are not in direct contact with pneumocytes
what does the interstitium contain?
- collagen and elastin fibres
- fibroblasts
- macrophages
what are the pores of kohn?
holes in alveolar walls
what are the functions of the pores of kohn?
- equalise pressure between adjacent alveoli
- help lungs to inflate easily and evenly during inspiration
- allow pneumonic infection to rapidly spread to multiple alveoli
what are the 2 layers of pleura?
(same membrane that reflects itself)
- adheres to outer surface of lungs
- adheres to inner surface of chest wall
what type of epithelia lines the visceral pleura?
flattened squamous mesothelial cells
what are the layers of connective tissue in the pleura?
- irregular internal elastic layer
- interstitial fibrocollagenous layer
- irregular external elastic layer
