Lecture #29: Pulmonary Histology Flashcards Preview

Histology -- Zach H. > Lecture #29: Pulmonary Histology > Flashcards

Flashcards in Lecture #29: Pulmonary Histology Deck (82):
1

What is the specific name of respiratory epithelium?

Pseudostratified Ciliated Columnar Epithelium

2

What are the names of the two portions that make up the respiratory system?

Conducting Portion and Gas Exchange Portion

3

What does the respiratory mucosa that lines the respiratory passageway consist of?

Pseudostratified Ciliated Columnar Epithelium
- lines most of conducting structures

Lamina Propria
- thin layer of loose connective tissue

Submucosa
- dense irregular connective tissue

4

What kind of epithelium lines the nares? Also, what glands and structures do you find within this epithelium?

>Stratified Squamous Epithelium (continuous with epidermis)

> Contains:
- sebaceous glands
- sudoiferous glands
- hair follicles

5

The mucosa in the nose begins at the level of the nasal septum. What does this mucosa include?

> respiratory epithelium

> basement membrane

> lamina propria (blends with underlying bone or cartilage)

> depending on location, mucosa may be called mucoperiosteum, mucoperichondrium, or the Schneiderian membrane.

6

True or False:

Olfactory epithelium is located on the nasal cavity floor and roof.

False - olfactory epithelium is located on the nasal cavity roof, only.

7

What different cell types make up the olfactory epithelium?

> Sustentacular Cells (support cells) with pigment granules.

> Basal Cells with pigment granules
- stem cells - give rise to immature olfactory cells

> Olfactory Cells
- bipolar neurons
- apical end projects into nasal cavity as a knoblike ending with nonmotile cilia
- cilia possess G-protein-linked odor-specific receptors
- basal end of the cell extends as an unmyelinated axon, bundled with other similar axons, through the ethmoid plate to mitral cells located in the olfactory bulb
- olfactory cells senesce and are replaced from basal cells

> Olfactory glands of Bowman

8

What type of cell is considered a support cell in olfactory epithelium?

Sustentacular cells (support cells) with pigment granules.

9

What type of cell, with pigment granules, gives rise to immature olfactory cells; thus is a stem cell?

Basal Cells (with pigment granules)

10

What type of neuron are olfactory cells?

Bipolar neurons

11

What kind of receptors do cilia of olfactory cells have?

Cilia possess G-protein-linked odor-specific receptors.

12

Is the basal end of the olfactory cell axon that extends through the ethmoid plate to mitral cells located in the olfactory bulb a myelinated or unmyelinated axon?

Unmyelinated axon


* basal end of the cell extends as an unmyelinated axon, bundled with other similar axons, through the ethmoid plate to mitral cells located in the olfactory bulb.

13

True of False:

The apical end of olfactory cells project into the nasal cavity as a knoblike ending with non-motile cilia.

True

14

What does the olfactory glands of Bowman secrete?

They secrete odorant-binding protein

15

What does odorant-binding protein, secreted by olfactory glands of Bowman, bind to?

Odorant-binding protein binds to odorant molecule in nasal cavity.

16

Describe the steps in the generation of an action potential starting at the odorant-binding protein + odorant molecule complex.

Odorant-binding protein + odorant molecule

binds to odorant receptor protein (G protein) on olfactory cell cilium

G-protein activated adenyl cyclase

ATP -> cAMp

Opening of sodium channels

Action potential

17

Look Over Figure 13-3

Have a big picture understanding of olfactory epithelium and its structure.

18

What makes up the mucosa of the nasopharynx?

> respiratory epithelium

> lamina propria:
- FECT
- mucous glands
- serous glands
- mixed glands
- diffuse lymphatic tissue


* FECT = fibroelastic connective tissue

19

What makes up the submucosa of the nasopharynx?

> Loose Connective Tissue

> MALT (mucosa-associated lymphoid tissue)

20

What is the Waldeyer's ring of the nasopharynx?

> Ring of lymphoid tissue around nasopharynx

> Includes tonsils and adenoids

21

What kind of cartilage makes up the core of the epiglottis?

Core of epiglottis consists of elastic cartilage.

22

What of the two surfaces of the epiglottis?

> lingual surface

> pharyngeal surface

23

What kind of epithelium covers the lingual surface of the epiglottis?

Covered with stratified squamous epithelium.

24

True or False:

The lamina propria of he lingual surface of the epiglottis has loose connective tissue and elastic fibers.

True

25

What kind of epithelium covers the pharyngeal surface of the epiglottis?

Covered with pseudostratified ciliated epithelium.

26

What type of glands are found in the lamina propria on the pharyngeal surface of the epiglottis?

Lamina propria with tubuloacinar seromucous glands.

27

What type of epithelium is the false vocal cords (vestibular folds) covered with?

Covered with pseudostratified ciliated epithelium.

28

What type of glands are found in the pseudostratified ciliated epithelium of false vocal cords?

Lamina with seromucous glands.

29

What type of epithelium covers the true vocal cords?

Covered with stratified squamous epithelium.

30

True or False:

True vocal cords have seromucous glands in the lamina propria like false vocal cords have.

False - true vocal cords lack seromucous glands in the lamina propria. False vocal cords (vestibular folds) have lamina propria with seromucous glands.

31

Given that the true vocal cords are part of the larynx and are covered with stratified squamous epithelium, what type of epithelium is found covering the remainder of the larynx?

Pseudostratified Ciliated Epithelium

32

What type of muscle is found in the larynx?

Skeletal Muscle

33

What types of cartilage are found in the larynx?

> Hyaline Cartilages
- thyroid, cricoid arytenoids

> Elastic Cartilages
- corniculates, curneiforms, tips of arytenoids, epiglottis

34

What types of epithelium make up the larynx?

1) Respiratory Epithelium
2) Stratified Squamous Epithelium

35

What kind of epithelium makes up the mucosa of the trachea?

Respiratory Epithelium with a thick basement membrane.

36

What kind of glands are found in the submucosa of the trachea?

Many sero-mucous gland are found in the submucosa of the trachea.

37

What closing the opening between the arms of the horseshoe-shaped cartilage in the trachea?

> FECT
> mucous membrane
> smooth muscles (trachealis muscles)

38

What makes up the adventitia of the trachea?

> 16-20 horseshoe-shaped cartilages interconnected by FECT.

> Opening between arms of horseshoe-shaped cartilages closed by:
- FECT, mucous membrane, and smooth muscles

> Mixed glands and capillaries

39

In the context of this lecture, the word "lung" refers to all the respiratory system components distal to the trachea. For our purposes, this includes the bronchial tree and the alveoli, which are actually terminations of the bronchial tree, as well as the connective tissue support system and vascular system.

From his lecture.

40

Histologically, we are mostly interested in the hierarchical changes that occur in the bronchial tree form the primary bronchi to the smallest divisions of the bronchial tree - the respiratory bronchioles - as well as the terminations of the bronchial tree - the alveoli.

From Dr. Anderson's Lecture.

41

What 3 components make up the blood-air barrier?

1) thin capillary endothelium (continuous endothelium)

2) thin epithelium of pneumocyte

3) intervening basal lamina produced by both cell types

42

What does the blood-air barrier permit?

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

43

What type of cells secrete surfactant?

Surfactant secreted by:
- Clara Cells
- Type II Alveolar Cells

44

What does surfactant function to do?

Surfactant reduces surface tension on alveolar surface.

45

What do type II alveolar cells do with old surfactant?

Phagocytize it

*Type II alveolar cells phagocytize old surfactant.

46

What does type II alveolar lamellar bodes contain?

Contain dipalmitoyl phophatidylcholine (lechithin)
- secreted from apical domain of cells
- combine with proteins from Clara cells

47

What percent of alveolar surface is covered by type I pneumocytes?

Type I pneumocytes cover about 95% of the alveolar surface.

48

True or False:

Tight junctions connect type I pneumocytes.

True

49

Is the cytoplasm of type I pneumocytes thin or thick?

Very thin cytoplasm

50

True or False:

Type II pneumocytes cannot divide and replace type I pneumocytes.

False - type II pneumocytes can divide and replace type I pneumocytes.

51

Where are Clara cells found?

Found only in bronchioles

52

What is the relationship between Clara cells frequency and ciliated columnar cells frequency?

Number of Clara cells increases as ciliated columnar cells decrease.

53

How is the Clara cell histologically identified?

Histologically, these cells can be identified by an apical surface that bulges into the lumen of the airway.

54

We have discussed that Clara cells secrete surface-active lipoprotein, but what exactly is its function?

Clara cells secrete surface-active lipoprotein that prevents collapse of terminal bronchioles during exhalation.

55

True or False:

Clara cells contain abundant SER.

TRUE

56

What are Dust cells and what are they derived from?

Dust cells are macrophages and are derived from monocytes.

57

What do Dust cells function to do?

Dust cells phagocytize particles such as pollutants, bacteria, and surfactant that are not trapped in the mucous and expectorated.

58

What role do Dust cells play in congestive heart failure?

>In CHF, fluid containing the breakdown products of hemoglaobin (iron-containing hemosiderin) leak into alveolar spaces and are phagocytized by the dust cells.

>The iron-containing dust cells are referred to as heart failure cells.

59

Define pore of Kohn.

The alveolar pores of Kohn connect adjacent alveoli. The pores are responsible for collateral respiration when blockage of a small bronchiole occurs. Thus, in case of a blockage, adjacent unobstructed bronchioles and associated alveoli continue to provide alveolar ventilation through the pores of Kohn.

60

Are primary bronchi extrapulmonary or intrapulmonary?

Extrapulmonary

61

Are the cartilage rings that reinforce primary bronchi circular or horseshoe-shaped like in the trachea?

The cartilage rings that reinforce primary bronchi are circular rather than horseshoe-shaped.

62

True or False:

Segmental (secondary) bronchi are mostly intrapulmonary.

True

63

What type of circle cartilage rings reinforce segmental (secondary) bronchi, and what does it transition into?

Segmental (secondary) bronchi are reinforced by circular rings of hyaline cartilage that transitions to irregular plates.

64

We are not concerned with the individual names for the various subdivisions of the bronchi. We will focus on the changes in the histology of the bronchial tree from the larger intrapulmonary bronchi to the respiratory bronchioles.

Generalization:
- as the bronchi become smaller there is a decrease in the height of the epithelium, a decrease in cartilage and glands, and an increase in the proportion of elastic fibers and smooth muscles.

Examine figures 13-6 and 13-7 for the general structure of the bronchial tree and the changes that occur from the segmental bronchi to the terminal bronchioles.

65

As the bronchi become smaller, what is the relationship between:
- height of epithelium
- cartilage and glands
- elastic fibers
- smooth muscles

As the bronchi become smaller there is a decrease in the height of the epithelium, a decrease in cartilage and glands, and an increase in the proportion of elastic fibers and smooth muscles.

66

What is the makeup of the mucosa of intrapulmonary bronchi?

Mucosa:
- similar to trachea and extra-pulmonary bronchi
- mucosal folds may be present due to smooth muscles
- elastic fibers are prominent

67

What is the submucosa of intrapulmonary bronchi characterized by and what does it contain?

> Characterized by loose CT and lymphatic tissue.

> Contains mixed glands and mucous glands.

68

What does the adventitia of intrapulmonary bronchi contain?

Contains hyaline cartilage plates surrounded by dense FECT.

69

What are the general characteristics of bronchioles?

> absence of cartilage

> absence of glands

> sparse goblet cells, especially in terminal bronchioles

> large amount of smooth muscle tissue

> diameter ranges from 1 mm to about 0.3 mm

> epithelium transitions from ciliated columnar with a few goblet cells to ciliated cuboidal with no goblet cells (terminal bronchioles)

> smallest bronchioles are the terminal bronchioles

> each terminal bronchiole branches to form two or more respiratory bronchioles

70

True or False:

Each terminal bronchiole branches to form two or more respiratory bronchioles.

True

71

Which bronchioles are the smallest?

terminal bronchioles

72

What is the epithelium transitions through the bronchioles?

Epithelium transitions from ciliated columnar with a few goblet cells to ciliated cuboidal with no goblet cells (terminal bronchioles).

73

What are the general characteristics of respiratory bronchioles?

> Diameter Epithelium of low columnar to low cuboidal

> Cilia present only in larger respiratory bronchioles

> Goblet cells absent

> Wall consists of smooth muscle within FECT

> May have a few alveolar outpocketings:
- because gas exchange may occur here for the first time in the respiratory tree, these bronchioles are referred to as respiratory bronchioles.

74

What does the wall of the alveolar duct consist of?

Alveolar duct wall consists of smooth muscle with FECT.

75

What kind of epithelium lines alveolar ducts?

squamous epithelium

76

What separate alveoli within alveolar sacs?

Alveoli within alveolar sacs are separated by alveolar septa.

77

You know that the walls of alveoli and septa are thin. What are they composed of?

> Type I alveolar cells (type I pneumocytes)
- less numerous than type II pneumocytes
- cover largest surface area

> Type II alveolar cells (type II pneumocytes)
- cuboidal or rounded
- serve as stem cells for type I and type II pneumocytes

> Macrophages (dust cells)

78

What are pores of Kohn?

Openings between adjacent alveoli.

79

What are the cell types in the mucosa of respiratory epithelium?

ciliated columnar cells

non-ciliated columnar cells

stem cells

80

What are goblet cells?

> mucous secreting cells
> also stem cells; can replace other cells of epithelium

81

What are neuroendocrine cells (small granule cells)?

> may be associated with sensory reception and are more prevalent in infants.

> release catecholamines

82

Do neuroendocrine cells release catecholamines?

Yes