Respiratory System Flashcards
What are the functions of the respiratory system?
- air conduction/gas exchange
- phonation
- olfaction
- heat regulation
- air temperature + moisture
- protection
- acid-base regulation
- hormone conversion
What are the different functional subdivisions of the respiratory system?
- conductive system: nasal cavity, pharynx, larynx, trachea, and bronchi
- transitional system: respiratory bronchioles
- gas exchange system: respiratory bronchiole and alveoli
What are feature of the conducting system?
- brings air to respiratory portion
- cleanses, moistens, and warms incoming air
- blood in venous plexuses in mucous membranes of nasal cavity warms incoming air
- hair and secretions in nasal cavity trap particulate matter
What are features of the transitional system?
- zone between the conducting (ciliated) and the gas exchange (alveolar system) areas of the respiratory tree
- consists exclusively of respiratory bronchioles (bronchioles in wall that possess outpocketings of gas exchange tissue)
What are respiratory bronchioles lined by?
- club cells
- non-ciliated secretory cells
- a few ciliated cells
- NO goblet cells in healthy bronchiole
What are features of the exchange system?
- composed of alveoli: thin walled structures enveloped by a rich network of capillaries (pulmonary capillaries)
Alveoli are lined by ___________ (membranous) and __________
- epithelial type i
- type ii pneumonocytes
What is the path of the respiratory system?
- nasal cavity > nasopharynx > larynx > trachea > bronchi > bronchioles > exchange > respiratory bronchioles > alveolar ducts > alveolar sacs > alveoli
What are the two kinds of defense mechanisms of the respiratory system?
- non-specific (non immune-mediated)
- specific (immune-mediated)
What are kind of non-specific defense mechanisms?
- mucous trapping
- mucociliary clearance
- phagocytosis
- air turbulence (generated by coughing/sneezing)
What are kinds of specific defense mechanisms?
- antibody production
- antibody-mediated phagoytosis
- cell-mediated immunity
What is the nasal cavity, pharynx, larynx, and bronchi mostly lined by?
- pseudostratified ciliated columnar epithelium
- with secretory goblet cells and submucosal serous cells
What is the arrow indicating? What part of the respiratory system is this found?
- tubulo-alveolar gland: mainly serous, with lesser numbers of mucous and mixed glands
- used for olfaction (bowman’s glands)
- nasal cavity (pseudostratified columnar epithelium w/ goblet cells)
What is indicated by the rectangle?
- lamina propria supported by submucosa
- (in nasal cavity)
The nasal cavity is a bone supported cavity within the skull divided by a cartilaginous nasal septum. Each half has 3 regions called:
- vestibular region
- respiratory region
- olfactory region
What are features of the vestibular region of the nasal cavity?
- initial, external part with a cutaneous muscle membrane, haired skin, and glands
- lined with stratified squamous keratinized epithelium
What are features of the respiratory region?
- largest part of the nasal cavity
- lined with pseudostratified columnar ciliated epithelium with goblet cells
- the cell combination is called mucociliary apparatus, responsible for clearance - conchae turbinates: projections from the lateral wall that narrow the nasal cavity and increase area of contact with air
What are feature of the mucociliary apparatus?
- cilia
- goblet cells
What is the function of the mucociliary apparatus?
- goblet cells produce mucinogen granules
- movement of cilia removes mucus with trapped airborne inhaled particles such as dust and microorganisms
- function as a cleaning apparatus
What are features of goblet cells?
- present along the airways to the level of large bronchioles
- secretion traps particulate matter
- reaction to injury:
- hyperplasia (increased #) in smokers
- metaplasia (change from ciliated pseudostratified epithelium to squamous stratified epithelium)
What are features of ciliated epithelial cells?
- each cell has ~250 cilia on its surface
- tips have “claws” of dyein
- cells connected via gap junctions
- dysfunction caused by immobile cilia syndrome (kartagener’s syndrome): dyein missing
What are features of the olfactory region?
- lined with olfactory epithelium: much thicker than respiratory epithelium
- lack goblet cells
- lamina propria contains serous olfactory glands and non-myelinated axons of CN1
- swell bodies
Label each epithelium type
- A: respiratory
- B: olfactory
What are features of olfactory epithelium?
- located in dorsal part of nasal cavity
- thick
- cells:
- olfactory neurons: smell = olfaction (CR1)
- supporting (sustentacular cells)
- basal cells: stem cells for others
- NO GOBLET CELLS
Both olfactory and respiratory regions are rich in __________ which are distended with blood
- venous plexuses aka SWELL BODIES
Label the features of olfactory mucosa
- A: axons of CN1
- B: basal cell
- G: serous olfactory gland
- O: olfactory neuron
- S: supporting cell
What are the purposes of the vomeronasal organ?
- chemoreception, sexual behavior (pheromone detection)
What are features of the larynx?
- includes cartilage, vocal folds, and skeletal muscle
- initially: stratified squamous epithelium
- after vocal chords: pseudostratified ciliated columnar epithelium
What is this image showing? What are some features?
- trachea
- rings of cartilage, incomplete dorsally
- connective tissue adventitia
- birds have complete cartilage rings
What is this image showing? What are some features?
- trachea
- lined by ciliated pseudostratified columnar epithelium
- lamina propria and submucosa not clearly differentiated
- serous glands
What is this? Label features?
- trachea
- A: hyaline cartilage
- B: perichondrium
- C: pseudostratified ciliated columnar epithelium
What is this? Label features?
- trachea
- A: cilia
- B: goblet cell
- C: basal cells
What is this image showing? What is a defining feature?
- bronchus
- plates of hyaline cartilage
- trachea bifurcates into the bronchi which enter the lung and branch extensively
What is this? Label features?
- bronchus
- lined by ciliated pseudostratified columnar epithelium
- smooth muscle surrounds the lamina propria followed externally by CT containing:
- circle: mixed bronchial glands
- arrow: plate of hyaline cartilage
- mixed seromucous glands secrete mucin, lactoferrin and lysozyme (bacteriostatic/cidal)
What part of the respiratory tract is this?
- bronchus
Label the features of this lung slide
- A: alveoli
- B: cartilage
- C: pulmonary artery
- D: bronchus
What is this feature? Label the arrows?
- bronchioles
- lack cartilage and glands
- A: terminal bronchioles
- B: respiratory bronchioles
What part of the respiratory system is this? What are some features?
- terminal bronchiole
- lined by ciliated cuboidal cells with few/ no goblet cells
What are the labeled features? Their functions?
- A: club cells (bronchiolar exocrine cells)
- located in terminal and respiratory bronchioles
- bulge at surface
- secretory: source of surfactant-like substance which aids in maintaining latency of airway
- metabolize airborne toxins, may have immune function
- metabolize xenobiotic compounds
- B: ciliated cells
What is indicated in this image of ___________?
- respiratory bronchioles
- ciliated cuboidal epithelium which becomes flattened distally
- incomplete muscularis mucosae
- respiratory bronchioles subdivide into alveolar ducts
- histological appearance of respiratory bronchioles is similar to that of terminal bronchioles, with the exception of alveoli interruption
What is shown in this image? What are some features?
- alveolar ducts
- part of exchange system and empty into alveolar sacs and alveoli
- simple squamous epithelium
- edge surrounding the opening of each alveoli contains smooth muscle cells
What are features of alveolar sacs?
- lack smooth muscle
- branches off of alveolar ducts
What are alveoli lined by?
- 2 distinct epithelial cells:
- pneumocytes type i
- pneumocytes type ii
What is indicated in this image?
- pulmonary edema
- alveolar spaces filled with proteinaceous fluid
What are alveolar pores (septal pores of kohn)?
- neighboring alveoli connect with each other via pores,providing equalization of pressure and collateral ventilation if a bronchiole is obstructed
- allow macrophage to pass from one aveolus to another
What are features of pulmonary interstitium?
- interconnecting network of interstitial stroma tissue supporting the blood and lymphatic vessels, nerves, bronchi, bronchioles, and alveoli
- bronchovascular interstitium - main bronchiand pulmonary vessels
- interlobar interstitium - separating pulmonary lobules and supporting small blood and lymph vessels
- alveolar interstitium - supporting alveolar walls that contain pulmonary capillaries and alveolar epithelial cells (no lymphatic vessels)
- pulmonary changes such as edema, emphysema, and inflammation can affect one or more of these interstitial compartments
What is pulmonary septum?
- diving wall composed of interstitium plus cells
What are features of alveolar septum?
- contain fibroblasts, capillaries
- “dust” cells
- collagen type III is present in alveolar wall
- collagen type I is present in conducting airways
- elastic fibers!
What are features of pneumocyte type i (squamous alveolar type i cell)?
- forms walls of alveoli
- 95% of alveolar surface area
- extremely thin, have occluding junctions to prevent fluid passage
- gas permeability is desired function
- NOT mitotic
- organelles are grouped around nucleus
What are features of pneumocyte type ii (granular alveolar type ii cell/granular pneumocyte/great alveolar cells)?
- 5% of alveolar surface area
- secretory cell
- surfactant is produced via lamellar bodies/granules
- can be mitotic > produces type i and type ii cells
What is indicted in this image? Which type pneumocyte is it?
- lamellar granules (contain recently synthesized surfactant)
- pneumocyte type ii
What are features of surfactant?
- mono-molecular layer of phospholipoprotein
- functions to reduce surface tension reducing effort needed to inflate alveoli, thus preventing alveolar collapse (known as atelectasis)
- constantly produced by type ii cells
- cortisol stimulates production of surfactant in fetus just prior to parturition
- absence of surfactant in newborns is known as a hyaline membrane disease
What is shown in this image?
- lung capillaries
What are features of the blood-air barrier?
- composed of:
- vascular endothelium
- basement membrane of endothelial cell
- basement membrane of type i pneumocyte
- cytoplasm of type i pneumocyte covered by surfactant
- basal laminae are fused alveolar + capillary endothelium
What is the pathway of the air-blood barrier?
What are the types of pulmonary macrophages?
- alveolar macrophages “PAMS’
- intravascular macrophages “PIMS’
What is pulmonary blood supply and innervation?
- pulmonary arteries (arterioles)
- capillaries (continuous)
- pulmonary veins
- lymphatic vessels to lymph nodes: drain towards hilum, none in alveolar walls
- innervated by the parasympathetic system via vagus nerve and sympathetic system via middle cervical and cervical thoracic ganglia
The pulmonary blood supply is dual, what does this entail?
- functional part: pulmonary arteries (unoxegenated to lungs)
- nutritive/trophic: bronchial arteries (oxygenated to lungs)
What is visceral pleura of the lung composed of?
- connective tissue and lined by simple squamous epithelium (aka mesothelial cells)
- interstitium is connective tissue that supports the bronchial tree and separates lung into lobules
