Respiratory Histology

Question 1

What are alveolar sacs?

Answer 1

2+ clusters of alveoli

Question 2

What is the order of path from a bronchiole to an alveolus?

Answer 2

terminal bronchiole –> respiratory bronchiole –> alveolar duct –> alveolar sac

Question 3

What is the function of the conducting portion of the respiratory system?
What parts make it up?

Answer 3

collects and warms air --> transmits to respiratory part
nasal cavities, sinuses
trachea
primary, secondary, and tertiary bronchi
bronchioles, terminal bronchioles

Question 4

At what point in the respiratory tract do you stop seeing goblet cells, glands, and hyaline cartilage?

Answer 4

in the bronchioles

Question 5

What type of epithelium lines the olfactory region of the nasal cavities?
How is it different than respiratory region?

Answer 5

pseudostratified ciliated columnar

much thicker and lacks goblet cells
has olfactory glands –> serous secretions that dissolve odorant molecules

Question 6

What are the characteristics of terminal bronchioles?

Answer 6

simple cuboidal epithelium w/ clara cells
increased elastic fibers
1-2 layers smooth muscle

Question 7

What are the 4 layers of the trachea?

Answer 7

mucosa (ciliated pseudostratified columnar w goblet cells)
submucosa (denser CT than lamina propria)
cartilage
adventitia - binds trachea to adjacent structures

Question 8

What are the characteristics of olfactory receptor cells/neurons?

Answer 8

have single dendritic process
nonmotile cilia w/ odorant receptors
ligand binds –> signal to olfactory bulb

Question 9

What is special about the lamina propria of the respiratory epithelium?

Answer 9

has a rich vascular network w/ complex set of capillary loops

Question 10

What layer of the trachea contains glands to coat the mucosa?

Answer 10

submucosa

glands = submucosal glands

Question 11

What are the characteristics of type I pneumocytes?

Answer 11

very flat, line almost the entire alveolar surface

create surface for gas exchange w/ capillaries

Question 12

What layer of bronchi contains the irregular cartilage plates?

Answer 12

submucosa

Question 13

What are the 3 regions of the nasal cavities?

Answer 13

nasal vestibule - just inside nostriles, lined by skin
respiratory region - inferior 2/3, lined w/ respiratory mucosa
olfactory region - upper 1/3, lined w/ olfactory mucosa

Question 14

How do goblet cells secrete mucus?

Answer 14

mucigen granules released through exocytosis –> combine w/ water –> mucus

Question 15

What are the characteristics of visceral pleura?

Answer 15

covered in mesothelium
underlying fibrous CT of collagen and elastic fibers
extends into lung as septa continuous w/ lung parenchyma
contains a lot of lymphatic vessels

Question 16

What is emphysema caused by?

Answer 16

smoking cigarettes

chronic inhalations of particulate material

Question 17

What layer of the trachea contains BALT?

Answer 17

epithelia

Question 18

What are the major characteristics of bronchioles?

Answer 18

airways < 1 mm
clara cells in epithelia
increased elastic fibers in epithelia
no submucosa or cartilage

Question 19

What is the function of nasal cavities?

Answer 19

adjust the temperature and humidity of inspired air (enhanced by large surface area from turbinate bones)

Question 20

What type of epithelium lines the respiratory region of the nasal cavities?

Answer 20

pseudostratified columnar ciliated with goblet cells

Question 21

What is pneumonia?

Answer 21

inflammation of lung tissue
air spaces filled w/ exudate containing WBCs, RBCs, and fibrin
enlarged capillaries congested w/ RBCs –> lung appears red, firm, and heavy

Question 22

What are the two types of drugs for asthma?

Answer 22

short term bronchodilators

long term corticosteroids

Question 23

What are the main types of cells in the alveoli?

Answer 23

type I and II pneumocytes

macrophages

Question 24

What are the major differences between bronchi and the trachea?

Answer 24

no regular rings of cartilage - irregular plates
smooth muscle layer present that is continuous in larger bronchi and loosely organized in smaller ones
fewer submucosal glands and goblet cells

Question 25

What type of tissue lines the pleura?

Answer 25

mesothelium

Question 26

What is emphysema?

Answer 26

chronic obstruction of airflow due to narrowing of bronchioles --> destruction of alveolar wall --> significant area for gas exchange is lost

Question 27

Where do olfactory neurons lie?

Answer 27

in the middle of the olfactory mucosa

Question 28

What are alveolar pores?

Answer 28

small openings that permit movement of air btw alveoli

Question 29

What are the characteristics of type II pneumocytes?

Answer 29

rounded cells that are 60% of the cells, but cover 5% of SA | secrete surfactant from lamellar bodies --> exocytosis

Question 30

What are basal cells of olfactory mucosa?

Answer 30

stem cells for olfactory receptor and supporting cells

Question 31

What are the main cell types in olfactory mucosa?

Answer 31

olfactory receptor cells basal cells brush cells supporting/sustentacular cells

Question 32

What type of epithelium is found in alveoli?

Answer 32

simple squamous

Question 33

What is an alveolar septum?

Answer 33

wall of alveolar capillaries surrounded by elastin and collagen fibers

Question 34

When do you stop seeing simple ciliated columnar epithelium and start seeing simple cuboidal?

Answer 34

in the small bronchioles

Question 35

What are clara cells?

Answer 35

cells that secrete lipoprotein surfactant for the lungs | found in bronchioles and terminal bronchioles

Question 36

At what point in the respiratory tract do you stop seeing ciliated cells?

Answer 36

after respiratory bronchioles (once you reach alveolar ducts)

Question 37

How does asthma affect the airway?

Answer 37

chronic inflammation --> brochiolar walls infiltrated w/ eosinophils, lymphocytes, and mast cells --> super thick epithelium w/ more goblet cells, thick BM and hyperplastic smooth muscle --> makes airway chronically smaller and harder to move

Question 38

What are alveolar rings?

Answer 38

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

Question 39

what length of respiratory tract is considered the trachea?

Answer 39

from larynx into the primary bronchi

Question 40

What type of epithelium lines the respiratory tract?

Answer 40

pseudostratified columnar ciliated epithelium with goblet cells (confined to airways)

Question 41

What is the purpose of the respiratory portion of the system? What parts make it up?

Answer 41

passes air to alveoli --> gas exchange | respiratory bronchioles, alveolar ducts, alveolar sacs

Question 42

How is the epithelium in bronchi different than the trachea?

Answer 42

cells shorter in height in bronchi fewer goblet cells increased elastic fibers in LP