Respiratory Tract Histology Flashcards Preview

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Flashcards in Respiratory Tract Histology Deck (53)
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1
Q

The ______ portion of the respiratory system begins as a system of cavities that collect and warm air and transmit that air to the respiratory portion

A

Conducting

2
Q

What structures are associated with the conducting portion of the respiratory system?

A
Nasal cavity
Paranasal sinuses
Nasopharynx
Trachea
Primary, secondary, and tertiary bronchi
Bronchioles, terminal bronchioles
3
Q

The ______ portion of the respiratory system passes air to the alveoli with the purpose of gas exchange to blood in capillaries

A

Respiratory

4
Q

What structures are associated with the respiratory portion of the respiratory system?

A

Respiratory bronchioles
Alveolar ducts
Alveolar sacs

5
Q

What is the role of the conducting portion of the respiratory system?

A

Collects and warms air, transmits it to respiratory portion

6
Q

What is the purpose of the respiratory portion of the respiratory system?

A

Passes air to alveoli with purpose of gas exchange

7
Q

What type of epithelium is the respiratory epithelium

A

Pseudostratified columnar ciliated

8
Q

What is unique about the pseudostratified columnar ciliated epithelium lining the respiratory tract?

A

It has the appearance of 2+ cell layers, but it is a simple epithelium

All the cells rest on the basement membrane with the nuclei located at varying levels

[note that cilia are NEVER present on true stratified epithelia]

9
Q

T/F: the pseudostratified columnar ciliated respiratory epithelium is confined to the airways

A

True

10
Q

Whate are the major cell types associated with respiratory epithelium?

A

Ciliated columnar epithelial cells
Nonciliated colmnar epithelial cells
Goblet cells

11
Q

What is the purpose of the nonciliated columnar cells that are found among the ciliated columnar cells in the respiratory epithelium?

A

They are typically stem cells responsible for regenerating epithelia throughout life

12
Q

_______ cells are modified columnar epithelial cells that synthesize and secrete mucous

A

Goblet

13
Q

Describe the cytoplasm and “stem” of goblet cells

A

Apical cytoplasm that contains a dense aggregation of mucigen granules

“Stem” is occupied by basal nucleus and crammed with organelles

14
Q

Goblet cells have apical cytoplasm that contains a dense aggregation of mucigen granules. How are these released?

A

Released by exocytosis, then combine with water to form mucus

15
Q

Visceral pleura is covered in a flattened ________, which is a simple squamous epithelium found as part of the serous membrane

There are underlying fibrous tissues of _______ and ______ fibers

A

Mesothelium

Collagen; elastin

16
Q

The visceral pleura extends into the lung as fibrous septa and is continuous with lung _________, serving the purpose of dividing it into lobes and structures; it contains extensive _______ vessels

A

Parenchyma; lymphatic

17
Q

How does the height of epithelium change from the trachea (highest part of conducting portion) to alveolar sacs (lowest part of respiratory portion) of the respiratory tract?

A

Fairly constant in conducting portion

Decreases significantly in respiratory portion

18
Q

How does the distribution of goblet cells change from the trachea (highest part of conducting portion) to alveolar sacs (lowest part of respiratory portion) of the respiratory tract?

A

Goblet cell distribution begins to decrease in secondary bronchioles and completely disappears after tertiary bronchi

[none in terminal bronchioles or respiratory portion]

19
Q

How does the distribution of ciliated cells and glands change from the trachea (highest part of conducting portion) to alveolar sacs (lowest part of respiratory portion) of the respiratory tract?

A

Ciliated cells stick around until just after respiratory portion begins

Glands begin to dcrease in secondary bronchi and disappear at the tertiary bronchi level

20
Q

How does the distribution of hyaline cartilage change from the trachea (highest part of conducting portion) to alveolar sacs (lowest part of respiratory portion) of the respiratory tract?

A

Gradually decreases beginning in the trachea, disappears after tertiary bronchi (none in terminal bronchioles or respiratory portion)

21
Q

How does the distribution of smooth muscle change from the trachea (highest part of conducting portion) to alveolar sacs (lowest part of respiratory portion) of the respiratory tract?

A

Steady distribution from trachea to tertiary bronchi, starts to decrease in terminal bronchioles, and stops just after respiratory portion begins

22
Q

How does the distribution of elastic fibers change from the trachea (highest part of conducting portion) to alveolar sacs (lowest part of respiratory portion) of the respiratory tract?

A

Elastic fibers are abundant from the trachea down to the terminal bronchioles, start to decrease in respiratory bronchioles, and end in the alveolar sacs

23
Q

The trachea is made up of C-shaped _____ cartilage and is under the control of the ______ muscle.

Its submucosa is rich in ________ glands. It is lined with respiratory epithelium and its distal end forms a ring of fibroelastic tissue. It is also associated with a ______ ______ rich in blood vessels.

A

Hyaline; trachealis

Seromucinous; lamina propria

24
Q

Describe the epithelia associate with the primary bronchus

A

Pseudostratified columnar ciliated

Cells shorter in height

Fewer goblet cells

25
Q

Describe the lamina propria of the primary bronchus

A

Increased elastic fibers; separated from submucosa by smooth muscle

26
Q

Describe the submucosa of the primary bronchus

A

Fewer seromucinous glands; incomplete cartilage plates

27
Q

Describe the epithelia associated with the bronchioles

A

Simple columnar ciliated

Fewer goblet cells

28
Q

Describe the lamina propria associated with the bronchioles

A

Increased elastic fibers

Prominent smooth muscle

29
Q

T/F: bronchioles do not have submucosa, airways are <1 mm diameter, and they are associated with hyaline cartilage

A

False: they do not have submucosa, airways are <1 mm diameter, and they are NOT associated with cartilage!!

30
Q

Smooth muscle controls what functions of the bronchioles?

A

Bronchoconstriction

Bronchodilation

31
Q

Describe the epithelia associated with terminal bronchioles

A

Simple columnar ciliated

Clara cells (secrete surfactant)

32
Q

_______ cells are nonciliated dome-shaped cells with granular cytoplasm and they secrete surfactant to reduce surface tension and prevent bronchiole collapse

A

Clara

33
Q

Describe the lamina propria associated with the terminal bronchioles

A

Increased elastic fibers; 1-2 layers of smooth muscle

34
Q

What are the levels of branching of the respiratory bronchioles?

A

Respiratory bronchioles branch into:

Alveolar ducts –> alveolar rings –> alveolar sacs –> alveoli

35
Q

Alveolar _____ end in alveolar sacs

A

Ducts

36
Q

Alveolar _____= 2+ clusters of alveoli

A

Sacs

37
Q

Alveolar ____ = aggregates of smooth muscle, collagen, and elastic fibers that form rings around alveolar ducts

A

Rings

38
Q

_____ = blind-ended sacs lined with pneumocytes

A

Alveoli

39
Q

Describe the epithelium associated with alveoli

A

Simple squamous, associated with supporting tissue and blood vessels

40
Q

How many types of pneumocytes are there?

A

2 - Type I and Type II

41
Q

______ ______ = wall of alveolar capillaries surrounded by elastin and collagen fibers

A

Alveolar septum

42
Q

______ ______ = small opening that permit movement of air between alveoli

A

Alveolar pores

43
Q

_______ ______ aka dust cells are also present in the alveoli

A

Alveolar macrophages

44
Q

What 3 components make up the “respiratory membrane”

A

Alveolar epithelium

Fused basement membranes of the alveolar epithelium and capillary endothelium

Capillary endothelium

45
Q

Which type of pneuomocytes lines almost the entire alveolar surface, creating surface for gas exchange, and is closely associated with capillaries?

A

Type I pneumocytes

46
Q

Which type of pneumocyte consists of rounded cells that comprise about 60% of the epithelium and secrete surfactant that prevents collapse during respiration?

A

Type II pneumocytes

47
Q

Type II pneumocytes are associated with ____ _____ that hold pulmonary surfactant after processing its components in the rough ER and golgi

A

Lamellar bodies

48
Q

What region of the respiratory tract would you find no cartilage, no submucosa, few goblet cells, prominent smooth muscle, and less than 1 mm diameter?

A

Bronchioles

49
Q

How would you distinguish between bronchioles and terminal bronchioles?

A

Bronchioles are first branches from primary bronchi, they still have prominent smooth muscle while the terminal bronchioles will have less smooth muscle

50
Q

Bronchioles have no cartilage, no submucosa, few goblet cells, prominent smooth muscle, and are les than 1 mm in diameter. What type of epithelium is associated with the bronchioles?

A

Simple columnar ciliated epithelium

[note that the bronchioles are the first area of transition from pseudostratified columnar ciliated]

51
Q

What type of epithelium is associated with the alveoli?

A

Simple squamous

52
Q

While viewing a section of an alveolus, you see that about 60% of the alveolar epithelial cells have a large rounded nucleus. What type of cells are these?

A. Goblet cells
B. Type I pneumocytes
C. Type II pneumocytes
D. Alveolar macrophages

A

C. Type II pneumocytes

[goblet cells are not found in alveoli, type I cells are thin, flat cells associated with gas exchange]

53
Q

Which of the following is covered by a flattened mesothelium and has extensive lymphatic channels?

A. Visceral pleura
B. Alveoli
C. Parietal pleura
D. Trachea

A

A. Visceral pleura