Respiratory Tract Histology

Question 1

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

Answer 1

Conducting

Question 2

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

Answer 2

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

Question 3

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

Answer 3

Respiratory

Question 4

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

Answer 4

Respiratory bronchioles
Alveolar ducts
Alveolar sacs

Question 5

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

Answer 5

Collects and warms air, transmits it to respiratory portion

Question 6

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

Answer 6

Passes air to alveoli with purpose of gas exchange

Question 7

What type of epithelium is the respiratory epithelium

Answer 7

Pseudostratified columnar ciliated

Question 8

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

Answer 8

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]

Question 9

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

Answer 9

True

Question 10

Whate are the major cell types associated with respiratory epithelium?

Answer 10

Ciliated columnar epithelial cells
Nonciliated colmnar epithelial cells
Goblet cells

Question 11

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

Answer 11

They are typically stem cells responsible for regenerating epithelia throughout life

Question 12

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

Answer 12

Goblet

Question 13

Describe the cytoplasm and “stem” of goblet cells

Answer 13

Apical cytoplasm that contains a dense aggregation of mucigen granules

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

Question 14

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

Answer 14

Released by exocytosis, then combine with water to form mucus

Question 15

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

Answer 15

Mesothelium

Collagen; elastin

Question 16

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

Answer 16

Parenchyma; lymphatic

Question 17

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?

Answer 17

Fairly constant in conducting portion

Decreases significantly in respiratory portion

Question 18

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?

Answer 18

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

[none in terminal bronchioles or respiratory portion]

Question 19

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?

Answer 19

Ciliated cells stick around until just after respiratory portion begins

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

Question 20

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?

Answer 20

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

Question 21

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?

Answer 21

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

Question 22

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?

Answer 22

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

Question 23

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.

Answer 23

Hyaline; trachealis

Seromucinous; lamina propria

Question 24

Describe the epithelia associate with the primary bronchus

Answer 24

Pseudostratified columnar ciliated

Cells shorter in height

Fewer goblet cells

Question 25

Describe the lamina propria of the primary bronchus

Answer 25

Increased elastic fibers; separated from submucosa by smooth muscle

Question 26

Describe the submucosa of the primary bronchus

Answer 26

Fewer seromucinous glands; incomplete cartilage plates

Question 27

Describe the epithelia associated with the bronchioles

Answer 27

Simple columnar ciliated Fewer goblet cells

Question 28

Describe the lamina propria associated with the bronchioles

Answer 28

Increased elastic fibers Prominent smooth muscle

Question 29

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

Answer 29

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

Question 30

Smooth muscle controls what functions of the bronchioles?

Answer 30

Bronchoconstriction | Bronchodilation

Question 31

Describe the epithelia associated with terminal bronchioles

Answer 31

Simple columnar ciliated Clara cells (secrete surfactant)

Question 32

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

Answer 32

Clara

Question 33

Describe the lamina propria associated with the terminal bronchioles

Answer 33

Increased elastic fibers; 1-2 layers of smooth muscle

Question 34

What are the levels of branching of the respiratory bronchioles?

Answer 34

Respiratory bronchioles branch into: Alveolar ducts --> alveolar rings --> alveolar sacs --> alveoli

Question 35

Alveolar _____ end in alveolar sacs

Answer 35

Ducts

Question 36

Alveolar _____= 2+ clusters of alveoli

Answer 36

Sacs

Question 37

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

Answer 37

Rings

Question 38

_____ = blind-ended sacs lined with pneumocytes

Answer 38

Alveoli

Question 39

Describe the epithelium associated with alveoli

Answer 39

Simple squamous, associated with supporting tissue and blood vessels

Question 40

How many types of pneumocytes are there?

Answer 40

2 - Type I and Type II

Question 41

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

Answer 41

Alveolar septum

Question 42

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

Answer 42

Alveolar pores

Question 43

_______ ______ aka dust cells are also present in the alveoli

Answer 43

Alveolar macrophages

Question 44

What 3 components make up the "respiratory membrane"

Answer 44

Alveolar epithelium Fused basement membranes of the alveolar epithelium and capillary endothelium Capillary endothelium

Question 45

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

Answer 45

Type I pneumocytes

Question 46

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

Answer 46

Type II pneumocytes

Question 47

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

Answer 47

Lamellar bodies

Question 48

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?

Answer 48

Bronchioles

Question 49

How would you distinguish between bronchioles and terminal bronchioles?

Answer 49

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

Question 50

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?

Answer 50

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

Question 51

What type of epithelium is associated with the alveoli?

Answer 51

Simple squamous

Question 52

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

Answer 52

C. Type II pneumocytes [goblet cells are not found in alveoli, type I cells are thin, flat cells associated with gas exchange]

Question 53

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

Answer 53

A. Visceral pleura