Lecture 8 1/29/24

Question 1

What are the characteristics of larynges in birds?

Answer 1

-two larynges present
-anterior larynx similar to mammals
-caudal larynx/syrinx found at caudal end of trachea by bifurcation

Question 2

What are the characteristics of the trachea in birds?

Answer 2

-overlapping, complete cartilage rings
-lined by resp. epithelium over glands
-increasing goblet cells and decreasing glands moving caudally
-lots of elastin fibers in submucosa

Question 3

What are the characteristics of the syrinx?

Answer 3

-voice box in birds
-located at tracheal bifurcation
-wall composed of internal and external tympanic membranes
-supported by intersyringeal cartilages and pessalus/bone wedge

Question 4

What are the characteristics of the bronchi?

Answer 4

-conduction portion
-trachea divides into primary bronchi
-extensive branching occurs of primary bronchi into secondary bronchi into tertiary bronchi
-increasingly narrow diameter leads to more inertia

Question 5

What type of epithelium lines the bronchi?

Answer 5

ciliated pseudostratified columnar that becomes flatter as the diameter becomes smaller (eventually cuboidal)

Question 6

What structures surround the bronchi?

Answer 6

-smooth muscle
-glands
-plates of cartilage
-collagen
-adjacent blood vessels
-BALT

Question 7

How do the bronchi walls change as the diameter narrows?

Answer 7

-folds in the bronchi increase with smaller diameter
-larger bronchi are more smooth

Question 8

What is BALT?

Answer 8

dense unencapsulated lymphoid tissue adjacent to the bronchi that provides immune surveillance

Question 9

What are the characteristics of the bronchioles?

Answer 9

-arise after the smallest branches of the bronchi
-no cartilage or glands
-surrounded by smooth muscle
-mucosa typically folded

Question 10

What happens to the epithelium as bronchioles become smaller?

Answer 10

-epithelium shortens and loses cilia with decreased diameter
-goes from ciliated, pseudostratified columnar to ciliated, simple cuboidal to non-ciliated, simple cuboidal

Question 11

What are the characteristics of terminal bronchioles?

Answer 11

-last of the strictly conducting portion
-cuboidal epithelium
-transitions to the respiratory bronchioles

Question 12

What are the characteristics of respiratory bronchioles?

Answer 12

-transition zone between conducting and gas exchange
-branch from ends of terminal bronchioles
-lined by cuboidal epithelium that flattens distally
-wall has smooth muscle
-alveoli in the walls

Question 13

What are the characteristics of club cells?

Answer 13

-located within respiratory bronchioles
-often indistinct
-make club cell secretory protein

Question 14

What are the effects of club cell secretory protein?

Answer 14

-anti-inflammatory
-important for metabolism

Question 15

What are the characteristics of alveolar ducts?

Answer 15

-branch from respiratory bronchioles
-entrance composed of circumferential smooth muscle
-walls composed of alveoli
-ducts branch into alveolar sacs

Question 16

What are the characteristics of alveolar sacs?

Answer 16

-groups of individual alveoli
-branch off the alveolar ducts
-gas exchange occurs within individual alveoli

Question 17

What are the characteristics of alveoli?

Answer 17

-where gas exchange occurs
-lined by type 1 and type 2 pneumocytes
-separated by alveolar septa composed of type 1 pneumocytes, collagen, and elastin

Question 18

What are the characteristics of type 1 pneumocytes?

Answer 18

-simple squamous
-very thin
-allows for gas diffusion

Question 19

What are the characteristics of type 2 pneumocytes?

Answer 19

-cuboidal
-thicker
-not good for gas exchange
-produce pulmonary surfactant
-proliferate to repair if type 1 pneumocytes are damaged

Question 20

What is the blood-air barrier?

Answer 20

fused basement membrane, endothelial cells, and type 1 pneumocytes

Question 21

What are the characteristics of the alveolar septa?

Answer 21

-composed of small amount of collagen and elastin
-allows for compliance/changes in size and shape

Question 22

What are the characteristics of alveolar macrophages?

Answer 22

-within alveolar lumens and septa
-provide immune surveillance and clean up

Question 23

What are the interlobular septa?

Answer 23

connective tissue (collagen) divisions between lung lobules

Question 24

What are the two blood supplies within the lungs?

Answer 24

-pulmonary vascular system (primary)
-bronchial vascular system (secondary)

Question 25

What is the blood flow path followed by the pulmonary vascular system?

Answer 25

-deoxygenated blood from right atrium
-pulmonary arterial trunk
-right and left pulmonary arteries at hilus along mainstem bronchi

Question 26

How do the arterial branches of the pulmonary vascular system arrange?

Answer 26

they follow the branches of the bronchi

Question 27

Which elastic arteries are seen in the pulmonary vascular system?

Answer 27

-proximal pulmonary artery
-main pulmonary trunk
-larger pulmonary arteries

Question 28

Which type of artery is seen at the level where bronchi become bronchioles?

Answer 28

muscular arteries

Question 29

What happens as the pulmonary arteries continue to follow the bronchi and bronchioles?

Answer 29

-become smaller
-become discontinuous in the pulmonary arterioles
-lead to pulmonary capillaries
-blood becomes oxygenated
-blood exits through pulmonary venules and veins

Question 30

What are the characteristics of the bronchial vascular system?

Answer 30

-minor system
-provides oxygenated blood to structures within the lung itself
-also follows bronchial tree

Question 31

What are the two types of pleura?

Answer 31

-visceral/covering lungs
-parietal/covering inner thoracic wall

Question 32

What type of epithelium forms the pleura?

Answer 32

simple squamous