Tracheobronchial tree - Gross anatomy and microscopic

Question 1

At which vertebral level does the trachea begin?

Answer 1

C6

Question 2

At what level does the trachea end?

Answer 2

T5

Question 3

What surrounding structurs of the trachea kept it open?

Answer 3

Cricoid cartilages - C shaped rings

Question 4

What structures are these in the trachea?

Answer 4

Question 5

Trachealis muscle is found at the end of cricoid C shape rings. What type of muscle is Trachealis?

Answer 5

Smooth muscle

Question 6

What type of epithelium lines the tracheal mucosa?

Answer 6

Ciliated Pseudostratified columnar

Question 7

The epithelium of the trachea has columnar ciliated epithelial cells. What cellls in the epithelium produce mucus?

Answer 7

Question 8

The respiratory mucosa is made up of the Epithelium and underlying lamina propria. What is the lamina propria?

Answer 8

thin layer of areolar connective tissue that lies underneath the epithelium of the mucosa (the white line under the epithelium in photo)

Question 9

What other type of cells found in the epithelial layer of the trachea help generate the epithelial population?

Answer 9

Stem cells (basal stem cells)

Question 10

The combination of the sweeping movements by the ciliated epithelium and mucus from the goblet cells form the mucociliary escalactor. What is the function of the mucociliary escalator?

Answer 10

• To trap inhaled particles and pathogens, moving them up the airways to be swallowed and destroyed

Question 11

Describe the contents of the respiratory submucosa

Answer 11

• Thick layer of connective tissue that surrounds the epithelium contains many glands
• Water secretions from the glands help humidify the inspired air

Question 12

The trachea branches into two bronchi, at a point called what?

Answer 12

The carina

Question 13

State the order of structures from trachea to alveolus

Answer 13

Trachea

Primary Bronchi

Secondary Bronci

tertiary Bronci

Bronchioles

Terminal Bronchioles

Respiratory bronchioles

Alveolar duct

Alveolar sac

Alveolus

Question 14

What surface anatomical landmark is a good going to where the trachae biforcates?

Answer 14

The sternal angle

Question 15

Describe the differences between the right left main bronchus

Answer 15

Right:

• Wider, shorter, descends more vertically

Left:

• Longer

Question 16

Within the lung, the main (primary) bronchi, splits in lobar (secondary) bronchi. Each secondary bronchi supplies a lobe of the lung - therefore, how many secondary bronchi would you expect for the right and left lung?

Answer 16

Right secondary bronchi - 3

Left secondary bronchi - 2

Question 17

The lobar (secondary) bronchi branch into tertiary (segmental) bronci. Each of these supplies a BRONCHOPULMONARY SEGMENT.

In the simplest terms, what are bronchopulmonary segments

Answer 17

Just subdivisions of lung lobes that are separated by connective tissue. There are 10 segements in the right lung and 8 in the left.

Question 18

Like trachea, bronchi also have cartilage (cartilage STOPS at bronchioles). Describe how they are different from the tracheal cartilages, and what happens to the amount of smooth muscle as we go down the bronchi?

Answer 18

• Still cartilage but becomes less frequent and in primary bronchi they are still C shaped, but by the tertiary bronchii, it is no longer circular and is just present as sporadic “plates”
• AS CARTILAGE BEGINS TO DECREASE, THE AMOUNT OF SMOOTH MUSCLE INCREASES

Question 19

The segmental (tertiary) bronchi go onto form Bronchioles. They do not contain any cartilage or mucus secreting. They have are dominated by SMOOTH MUSCLE. Given the presence of smooth muscle, what is the likely function of this muscle?

Answer 19

• Brochodilation (sympathetic)
• Bronchoconstriction (parasympathetic)

Question 20

Describe the type of cells found in the epithelium found in bronchioles

Answer 20

• In LARGER bronchioles, the columnar cells are CILIATED
• In SMALLER bronchioles, the columnar cells are NON-CILIATED
• NO GOBLET CELLS
• Have Club cells (also known as Clarssa cells) - which secrete SURFACTANT - prevents the airways sticking together

Question 21

Respiratpry bronchioles are connected to alveoli along regions known as what?

Answer 21

Alveolar ducts

Question 22

What are the chambers called that contain many individual alveoli(alveolus)?

Answer 22

Alveolar Sacs

Question 23

What type of epithelium do alveoli have?

Answer 23

Siimple squamous

Question 24

What cells are the main cells involved in gas exchange in the alveoli?

Answer 24

Type 1 Pneumocytes

Question 25

What is the role of type 2 pneumocytes in alveoli?

Answer 25

Produce a surfactant, which reduces surface tension in the alveoli, making it less likely for the alveolar walls to collapse.

Question 26

What is the immune cell found on the alveolar surfaces?

Answer 26

• Alveolar macrophages (also known as dust cells)
• Remove debris and pathogens

Question 27

The site of gas exchange occurs at the respiratory membrane of alveoli. What are the 3 layers of the respiratory membrane?

Answer 27

• Alveolar epithelium
• Endothelial endothelium
• And in between, the FUSED basement membranes of the alveolar and endothelium cells

Question 28

What is the typical disatnce of the respiratory membrane? What does this small

Answer 28

0.1um to 0.5um - allows for rapid gas exchange

Question 29

Study the basic layers of the the mucous membrane