Exam 3 - lecture 21 Pulmonary Histology

Question 1

What is the epithelium that lines nares ?

Answer 1

• Stratified squamous epithelium contunous with epidermis
• contains sebacous glands, sudoriferous glands, and hair follicles

Question 2

What are the characteristics of the respiratory epithelium ?

Answer 2

• The respiratory system consists of a conducting portion and a gas excahgne portion
• Respiratory muscosa lines the respiratory passagway and is made of ……
  
  • psuedotratified ciliated columnar epithelium
    
    • respiratory epithelium
    • lines most of conducting strutures
  • Lamina propria
    
    • thin layer of loose connective tissue
  • submucosa
    
    • dense irregular connective tissue

Question 3

What are the cells that make up the olfactory epithelium?

Answer 3

• Susentacular cell
• basal cell
• olfactory cell
• glands of bowman

Question 4

What is a sustentacular cell?

Answer 4

support cells) with pigment granules

Question 5

What is a basal cell?

Answer 5

stem cells that give rise to immature olfactory cells

Question 6

what is an olfactory cell?

Answer 6

• BIpolar neurons
• apical end projects into nasal cavity as a knoblike ending with nonmotile cells
• cilia posses G protein linked odor specific receptors
• basal end of the cell extends as an unmyelinated axon, bundled with other similiar axons, through the ethmoid plate to mitral cells located in the olfactory bulb\Olfactory cells senesce and are replpaced from basale cells

Question 7

what are glands of bowman?

Answer 7

• Located in the lamina propria
• secrete odorant-binding protein
• odorant binding protein binds to odorant molecule in nasal cavity

Question 8

What kind of tissues (including epithelium) that are found in various parts of the larynx?

Answer 8

• Epiglottis
  
  • Lingual surface
    
    • Covered with stratified squamous epithelium
    • lamina propria with loose Ct and Elasic fibers
  • Pharygeal Surface
    
    • covered with pseudostratified ciliated epithelium
    • lamina propria with tubloacinar sermucous glands
  • core of epiglottis consists of elastic cartilage
• False vocal cords (vestibular folds)
  
  • covered with pseudostratified ciliated epithelium and tip covered by squamous epithelium
  • lamina with seromucous glands
• True Vocal Cords
  
  • Covered with stratified squamous epithelium
  • lack seromucous glands in lamina propria
• Remainder of larnyx is covered with pseudostratified epithelium

Summary

• Epithelium
  
  • respiratory epithelium (pseudostratified ciliated columnar)
• Cartilage
  
  • hyaline cartilages
    
    • thyroid, cricoid, aryenoids
  • Elastics cartilages
    
    • corniculates, cuneiforms, tips of arytenoids, epiglottis
• Muscle
  
  • skeletal muscle

Question 9

What is the histology of the three layers of the trachea

Answer 9

• Mucosa
  
  • respiratory epitelium with thick basement membrane
  • lamina propria with delicate FEECT and lymphatic tissue
• Submucosa
  
  • many sero-mucous glands
• Adventitia
  
  • 16-20 horse show shaped cartilages interconnected by fect
  • Opening between arms of horseshoe shaped cartilages closed by
    
    • FECT, Mucous Membrane, and Smooth muscles (trachealis muscles)
  • Mixed glands and capillaries

Question 11

What are the componets of the respiratory system?

Answer 11

• Nose and olfactory mucosa
• paranasal sinuses
• pharynx
• larynx
• trachea
• lung

Question 12

What is the histology of the nose?

Answer 12

• contains the nares
  
  • squamous epithelium with epidemrmis
• mucosa begins at level of nasal septum; includes:
  
  • respiratory epithelium (pseudtratidied ciliated columnar epithelium)
  • Basement membrane
  • Lamina Propria (blends with underlyning bone or cartilage)
  • depending on location, mucosa may be called mucoperiosteum, mucoperichondrium, or schneiferian membrane.

Question 14

What is olfactory epithelium?

Answer 14

• located in nala cavity roof
• pseudostratified columnar epithelium without globet cells
• no distinct basement membrane
• includes
  
  • sustentacular cells
  • basal cells
  • olfactorycells
  • olfactory glands of Bowman

Question 15

What is the histology of the nasopharynx?

Answer 15

• Mucosa
  
  • respiratory epithelium
  • lamina propria with FECT, mucous glands, serous, and mixed glands and diffuse lympatic tissue
• Submucosa
  
  • loose CT
  • MALT (mucosa-assocatied lympoid tissue around nasopharynx)
• Waldeyers RIngs
  
  • Ring Lympoid tissue around the nasopharynx
  • includes tonsils and adenoids

Question 16

What is the lung?

Answer 16

• Refers to all the respiratory system components distal to the trachea. This includes the broncial tree and alveoli and CT tissue support system and vascular system
• two lungs divided into lobes.
• three on the right and two on the left

Question 17

What are the Bronchus (bronchi) ?

Answer 17

• Trachea divides into two primary bronchi one to each lung.
• Lie outside of the lung and are refered to as extrapulmonary
• reinforced by circular cartilage rings
• Each primary bronchus divides into three (to the right lung) and two (to the left lung) (secondary bronchi also refered to as lobar bronchi)
  
  • lobar bronchi are mostly intrapulmonary
  • thes bronchi reinforced by circular rings of hyaline cartilage transition to irregular plates
• As bronchi become smaller there is a
  
  • decrease in the height of the epithelium
  • decrease in cartilage and glands
  • increase in the proportion of elastic fibers and smooth muscles

Question 18

What are the aveolar ducts?

Answer 18

• Continuations of respiratory bonchioles
• cone shaped
• squamous epithelium
• Wall consists of smooth muscle with FECT

Contains alveolar sacs where each sac is composed of several alveoli

Question 19

What are alveoli?

Answer 19

• contained with alevolar sacs seperated by albeolar septa
• Walls of alveoli and septa are thin and composed of
  
  • Type 1 alveolar cells (type 1 pneuocytes)
    
    • less in nymber than type 2
    • cover largest surface area
  • Type II alveolar cells (type 2 pneumocytes)
    
    • Cubodial or rounded
    • serve as stem cells for type 1 and type 11 pneumocytes
  • macrophages (dusts cells)
  • Pores of Kohn
    
    • openings between adjacent alveoli

Question 20

What are the differnces between type 1 pneumocytes and type 2 pnemocytes ?

Answer 20

• Type 1 pneumocytes
  
  • Very thin cytoplasm
  • Cover about 95% of the alveolar surgace
  • Tight junctions connect with other type 1 cells
  • Basal Lamina may be fused with basal lamina of nearby capillaries
• Type 2 pneumocytes
  
  • Rounded cells that bulge into the alveolar lumen
  • cover about 5% of the alveolar surface
  • can divide and replace type 1 pneuocytes

Question 21

What are neuroendocrine cells?

Answer 21

• Small granule cells
• may be associated with sensory reception and are more prevelent in infants
• release catecholamines

Question 22

What are clara cells ?

Answer 22

• Cells are found only in brochioles
• number of clara cells increases as ciliated columnar cells decrease
• apical surface that plunges into lumen of airway
• secrete surface active lipo protein that prevense collapse of bronchioles during exhalation
  
  • SURFACTANT
• contain abundant rER

Question 23

What are dust cells?

Answer 23

• Dust cells are macrophages and derived from monocytes
• dust cells phagocytize particles such as polluatants, bacteria, and surfactant that are not trapped in the mucous and expectorated
• in congestive heart failure, fluid containing the breakdown products of hemoglobin (iron containing hemosiderin ) leak into alveolar spaces and are phagocytized by dust cells
  
  • IRon containing duist cells referred to as heart failure cells

Question 24

What are the 3 componets of the blood air barrier ?

Answer 24

• THin capillary endothelium (continuous endothelium)
• Thin epithelium of pneumocyte
• Intervening basal lamin produced by both types

Permits gas exchange but does not allow fluids or cells to enter alveoli ( normally)

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