TOB Respiratory (16)

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TOB Respiratory (16)
2013-10-29 17:21:59
Tissue Organ Biology

Exam 4
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  1. What are the different components of the respiratory system?
    • 1. Ventilating mechanism
    • 2. Conducting portion
    • 3. Respiratory Portion
    • 4. The Defense Mechanism
    • 5. The Blood and Lymphatic vessels
    • 6. The Nerves
    • 7. The Pleura
  2. Ventilating mechanism
    • mechanism that moves air in (inspiration) & out (expiration) of the lungs
    • it includes the diaphragm, rib cage, intercostal muscle, abdominal muscles, & lung elastic CT
  3. Conducting portion
    • includes structures that carry air to & from sites of gas exchange while warming, moistening, & cleansing it
    • no gas exchange takes place IN the conducting portion because the walls of the structures are too thick
  4. What is the path air flows through in the conducting portion of the respiratory system?
    nasal cavity --> nasopharynx --> larynx --> trachea --> bronchi --> bronchioles --> terminal bronchioles
  5. respiratory epithelium
    • an epithelium that covers the surfaces of the conducting portion and is made up of several cell types
    • b/c of how thick it is, no gas exchange takes place across it
  6. Respiratory Portion
    • where gas exchange takes place, specifically in the thin-walled alveoli
    • order: respiratory bronchioles --> alveolar ducts --> alveolar sac --> alveoli
  7. Defense Mechanism
    cleans the air & inactivates harmful agents
  8. blood & lymphatic vessels
    a vast network of capillaries for rapid gas exchange, associated with arteries, veins & lymphatics
  9. respiratory nerves
    • they control breathing & change the diameter of the airways
    • there are some sensory nerves as well
  10. Pleura
    the lung coverings: double-walled sac divided into parietal & visceral layers
  11. ciliated columnar cells
    move mucous film and dirt particles out of the respiratory system
  12. goblet cells
    secret mucus that forms a film on the surface of the epithelium
  13. brush cells
    • contain numerous microvilli and may be involved in fluid absorption or
    • chemoreceptor function
  14. neuroendocrine (Kulchitsky’s) cells
    • contain peptide hormones and catechol amines
    • are part of DNES (diffuse neuroendocrine system)
    • can't be observed using H&E
  15. basal reserve cells
    differentiate into other cells type when the need arises
  16. basement membrane (basal lamina)
    • made up of 3 parts
    • 1. lamina lucida
    • 2. lamina densa
    • 3. lamina reticularis: made of fine fibrillary collagen (thickens in asthma + other inflammatory airway conditions)
  17. layers of the respiratory tract wall
    • inner --> outer
    • 1. epithelium: pseudostratified, ciliated, columnar (+ goblet cells)
    • 2. lamina propria: contains collagen, elastic fibers, seromucous glands
    • 3. smooth muscle: controls luminal diameter
    • 4. adventitia: contains cartilage, collagen & elastic fibers
  18. How does the thickness and complexity of the wall change as the diameter of the conducting structures decreases with each dichotomous branching?
    • both the thickness & complexity decrease
    • *while the surface area to volume ratio INCREASES
  19. Elastic fibers are found in which 2 portions of the respiratory system?
    • conducting & respiratory portion
    • provide structures w/ flexibility, allowing them to retract at expiration & force air out
    • destruction of elastic fibers causes some of the pathogenesis of emphysema & other respiratory system diseases
    • respiratory epithelium
    • can see pseudostratified epithelial cells
    • can see the cilia at the top
    • dark line under cilia = basal bodies; don't have that on villi
    • not great goblet cells
    • goblet cells visualized in respiratory epithelium
    • goblet cells don't have cilia b/c they open up & exocytose their contents (mucus granules
  20. How does the skin type change from the nares (nostrils) to the inner vestibules & nasal fossae?
    • outside & nares: stratified squamous keratinized
    • to mucous membrane
    • vestibule + nasal fossae: respiratory epithelium
  21. vibrissae
    coarse short hairs that filter and trap large particles from inspired air
  22. nasal fossae
    • located posterior to the vestibules
    • on the lateral fossae wall there are three turbinates (bony conchae) that slow the incoming air flow and condition it (clean, warm, moisten)
  23. swell bodies
    • venous plexus in the conchal mucosa that every 20-30 minutes on each side become engorged with blood
    • air flow on the swollen side is restricted, limiting drying of mucosal surfaces
  24. superior concha
    • roof and upper third of the nasal septum
    • a small area above it is covered by olfactory mucosa, a thick epithelium with sustentacular (supporting) cells, olfactory nerve cells, & basal cells
  25. Bowman’s (Serous) glands
    • located in the submucosa above the superior concha secrete a fluid which washes over the surface epithelium
    • all odorants (things to smell) dissolve in this liquid and bind to receptors on the olfactory cells
    • everything you smell has to be in fluid form
  26. olfactory nerve cells
    • bipolar neurons with modified, non-motile cilia present at knob-like endings
    • receptors for odorants are present on the surface of the CILIA - such cells turn over constantly (unusual for CNS)
  27. Paranasal Sinuses
    • sinuses lined with mucous membrane continuous with the nasal mucosa
    • ciliated cells move the mucus secreted by the goblet cells
    • oftentimes filled with mucus material during a cold
    • Larynx
    • this portion of conducting pathway isn't covered by respiratory epithelium - larynx contains stratified squamous epithelium (SSNKE)
    • contains vocal chords & vocalis muscle that controls the vocal chords
    • several cartilages (most hyaline, a few elastic) anchor the vocalis muscle
  28. epiglottis
    • directs food away from the airway during swallowing
    • has non-keratinized stratified epithelium on its superior surface and has respiratory epithelium on its inferior surface
    • lamina propria contains some seromucous glands + an elastic cartilage plate
  29. vocal apparatus
    • consists of:
    • vestibular folds (false vocal cords) - respiratory epith.
    • true vocal cords - stratified squamous epith, control phonation
    • each true vocal cord has a large elastic fiber bundle, vocal ligament, & a parallel SKELETAL muscle bundle, the vocalis muscle
    • Trachea
    • hollow tube organ with mucosa, submucosa, & an adventitia segmented by C-shaped hyaline cartilage in the adventitia
    • it's open in the posterior portion (near the esophagus) and here trachealis muscle (smooth muscle) + elastic tissue bridge the free ends
  30. what the layers of the trachea contain
    • mucosa (innermost layer, closest to lumen): covered by respiratory epithelium, has a PROMINENT basement membrane, & an underlying lamina propria
    • submucosa: contains MANY seromucous glands & is separated from mucosa by a layer of elastic fibers
  31. primary (chief/main/principle) bronchi
    near the lungs, the trachea branches into two of them, one for each lung; have a similar histology to that of the trachea
  32. Which lung do aspirated foreign materials tend to enter more readily?
    • the RIGHT one
    • this is because the right primary bronchus is wider, shorter & more VERTICAL than the left, and it makes a smaller angle with the axis of the trachea than the left (more room for things to enter)
    • trachea cross-section
    • top: film of mucous
    • underneath wave: respiratory epith.
    • under that: lamina propria
    • *if there is no smooth muscle and only CT, must be trachea
    • bubbles: seromucous glands
    • bottom layer: hyaline cartilage
  33. Subdivisions of the Lungs
    • divide into smaller & smaller compartments
    • Lobes
    • Bronchopulmonary segments
    • Acinus (Terminal Respiratory Unit)
    • Secondary lobules
    • Primary lobules
  34. What separates the different bronchopulmonary segments from each other?
    • connective tissue septa
    • right lung: divided into three lobes, each with its secondary bronchus
    • left lung: divided into two lobes and thus two secondary bronchi
    • can theoretically remove one bronchopulmonary segment without affecting other parts of the lung because they each have their own blood supply & conducting airway
  35. Intrapulmonary Bronchi
    • aka cartilaginous airways that arise from subdivisions of the primary bronchi via dichotomous branching
    • intrapulmonary bronchi themselves divide a lot to give rise to lobar & segmental bronchi
    • as bronchial diameter decreases, the thickness & complexity of the wall decreases
  36. generation
    the name given to each bronchi branching; there can be as many as 23 generations of branching for the conducting airway
  37. bronchial fluid
    formed from secretions of seromucous glands in the submucosa and goblet cells in the respiratory epithelium
  38. bronchi adventitia
    contains pieces of cartilage in the form of “plates” or “islands” which may calcify with aging
    • intrapulmonary bronchus histological features
    • inner respiratory epithelium
    • *SMOOTH MUSCLE BAND - muscularis mucosa
    • can see islands of HYALINE cartilage in the adventitia (outermost layer, circles, dark purple blobs)
    • Bronchioles - membranous airways
    • larger bronchioles' lumen = lined by respiratory epithelium
    • smaller bronchioles' epithelium = may contain Clara cells
    • muscularis mucosa of the bronchiole is THICK relative to the diameter of the tube; the smooth muscle controls bronchioles' diameter
    • *adventitia doesn't contain cartilage or glands; is made up of CT w/ abundant elastic fibers
    • high magnification of bronchioles
    • smooth muscle [increases with asthma, decreased lumen diameter]
    • no glands
    • NO cartilage (much less resistance)
    • Clara/Club cells
    • non-ciliated, dome-shaped apex, with the ultrastructure of a protein secreting cell
    • 1. have abundant smooth ER, rich in cytochrome P450, & are involved in detoxifying chemicals we inhale
    • 2. CCSP (clara cell secretory proteins) contribute to the bronchial fluid & reduce surface tension (bronchiolar surfactant)
    • 3. act as progenitor cells of the bronchiole epithelium during regeneration and repair
  39. Terminal Bronchioles
    • smallest, last portion of the conducting pathway
    • epithelium contains Clara/Club cells & some cuboidal ciliated cells (to remove any mucous which might move this far)
    • lamina propria consists of collagen + elastic fibers
    • muscular layer is made up of an incomplete circular layer of smooth muscle
    • each terminal bronchiole divides into 2 or more respiratory bronchioles
  40. respiratory bronchioles
    • make up the first part of the respiratory portion
    • cuboidal epithelium (with ciliated cells, goblet cells & clara/club cells) is similar to that of a terminal bronchiole BUT the wall is interrupted by alveoli
  41. as the respiratory bronchioles divide, the number of
    • alveoli in the walls __________, but the number of goblet & ciliated cells ___________
    • alveoli increase in number
    • goblet cells disappear
    • frequency of ciliated cells decreases
  42. alveolar ducts
    • the last generation of respiratory bronchioles
    • they give rise to alveolar ducts
    • their wall consists almost completely of alveolar sacs & the lining is made up of small ‘knobs’ of smooth muscle covered by cilia-free simple cuboidal cells
  43. atria & alveolar sac
    atrium = distal termination of an alveolar duct; it leads to several alveolar sacs: multiple alveoli wrapped in elastic fibers
    • left: terminal bronchiole
    • right: see bubbles = alveoli [that's how you know the left portion is the terminal bronchiole]

  44. pulmonary lobule
    • made up of a terminal bronchiole + the associated structures distal to it (several respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli)
    • separated from other lobules by connective tissue septa
  45. acinus (terminal respiratory unit)
    • the functional unit of the lung: where gas exchange takes place
    • includes all the structures distal to a respiratory bronchiole (alveolar ducts, alveolar sacs, and alveoli)
  46. Alveolar Pores (of Kohn)
    • small pores that may interrupt alveolar septum & connect one alveolus to another
    • they equalize pressure and allow collateral air flow, important when small airways are blocked
    • can also play a role in the spread of infection from one alveolus to another
  47. Type I Alveolar Cells
    • simple squamous epithelial cells that make up 97% of the alveolar surfaces
    • most of the cell is flattened into a thin sheet which forms part of the blood-air barrier
    • their nucleus & organelles are clustered together in the ‘thick’ part of the cell
    • alveolar type II cell (septal cell)
    • cuboidal cells w/ round nuclei found among the type I cells at the ‘corners’ of the alveoli
    • have mitotic capacity
    • are responsible for regeneration/repair of the alveolar surface
    • secret pulmonary surfactant packaged in multilamellar bodies (cytosomes) to reduce the surface tension at the air-blood interface
  48. Surfactant
    • a mixture of lipids, proteins, and a little carbohydrate
    • lipids are mainly phospholipids (dipalmitoyl phosphatidyl-choline
  49. What surfactant phospholipid appears late in fetal development and can be used as an indicator of lung maturation?
    phosphatidyl glycerol
  50. gas exchange
  51. How does the pulmonary system defend against pathogens?
    • 1. goblet cell, seromucous gland, clara cell, & immune cell SECRETIONS
    • 2. mucociliary clearance mechanism (back up to throat)
    • 3. alveolar macrophages
    • 4. immune/inflammatory cells in the interstitium (eg. macrophages, lymphocytes, plasma cells)
    • black spots = alveolar macrophages, or DUST CELLS
    • they crawl on the surface of the alveoli and ingest surfactant, bacteria, viruses, & duct particles
    • BALT (bronchus associated lymphoid tissue)
    • because airways are inward extensions of the outside world, lymphoid aggregates [BALTS] can be found in the walls of the tubes
    • it's a type of MALT (mucosa associated lymphatic tissue)

  52. Two main suppliers of blood (blood vessels) of the Lung
    • 1. Pulmonary Arteries: carry deoxygenated blood
    • comes from the pulmonary trunk
    • runs WITH conducting airways (share adventitia)
    • low pressure/resistance system
    • thin walled
    • END as capillary networks
    • 2. Pulmonary Veins: carry oxygenated blood
    • usually run by themselves
    • aren't connected to the conducting airway (separated by a sea of alveoli)
    • pulmonary vein
    • thin walled blood vessel surrounded by "a sea of" alveoli
    • in the pulmonary system/lungs will carry OXYGENATED blood
  53. Bronchial Arteries & Veins

    • supply nutrients to & remove waste from pulmonary tissues
    • are NOT involved in gas exchange
    • arteries (typically muscular) carry oxygenated blood
    • veins (small) carry deoxygenated blood
    • are both found IN the walls of the bronchial tree
  54. pleura
    • double layer serous membranes made of simple squamous/low cuboidal mesothelial cells
    • visceral pleura: envelops the lungs proper, is continuous with the
    • parietal pleura: adherent to the thoracic wall
    • between the two layers is a film of clear serous fluid that serves as a lubricant, allowing the layers to move against each other during breathing with minimal friction