Respiratory system week 3

Question 1

Components of the conducting zone of respiratory tract (RT)

Answer 1

nose, pharynx, larynx, trachea, bronchi, bronchioles and terminal bronchioles

Question 2

Components of respiratory zone of RT

Answer 2

respiratory bronchioles, alveolar ducts, alveolar sacs and the alveoli

Question 3

Components of the upper RT

Answer 3

nasal cavity through the start of larynx

Question 4

Components of the lower RT

Answer 4

larynx through to the lungs also contains the whole respiratory zone

Question 5

functions of nasal passage (4)

Answer 5

1. warms and humidifies air
2. removal and retention of pathogens/particulate matter (anything bigger than 5-10 nm
3. olfaction
4. trap and drain paranasal sinuses and lacrimal ducts

Question 6

What are turbinates?

Answer 6

bone shelf projections, force air into a regular steady flow over mucosal surfaces

Question 7

What are the components of the mucosa?

Answer 7

• Lamina propria- complex capillary loop system to heat inspired air
• Seromucus glands release water to humidify air and trap air impurities
• Lots of IgA produced by plasma B cells

Question 8

What are the two types of epithelium in the nasal passage?

Answer 8

1. Respiratory epithelium(ciliated pseudostratified columnar) found on inferior and middle turbinates and rest of conducting portion of system
2. Olfactory epithelium (specialized pseudostratified) and covers the superior turbinate and roof of nasal cavity.

Question 9

Components of olfactory epithelium

1. olfactory neruons

Answer 9

ciliated bipolar olfactory neurons with membrane chemoreceptors(axons from CN I)

Question 10

Components of olfactory epithelium

2. supporting cells

Answer 10

pseudostratified columnar cells that support the olfactory cells

Question 11

Components of olfactory epithelium

3. basal cells

Answer 11

the stem cells that replace every 2-3 months

Question 12

Components of olfactory epithelium

4. Brush cells

Answer 12

columnar cells with microvilli. Afferent conncection to CN V (trigeminal)

Question 13

Components of olfactory epithelium

5. lamina propria contains Bowman’s glands

Answer 13

olfactory glands-produce liquid to facilitate odor detection

Question 14

The larynx

Answer 14

• passage of air between pharynx and trachea
• rigid wall for protection
• cartilage movements participate in sound production during phonation
• Serves as gate for GI and RT via epiglottis

Question 15

Histology of larynx

Answer 15

• lingual surface has stratified squamous epithelium
• transition to respiratory epithelium that covers vestibular folds
• vocal cords are covered with stratified squamous epithelium

Question 16

Trachea

Answer 16

larynx to carina
16-20 C-shaped hyaline cartilage rings
100-120 mm long and 25 mm in diameter
C-rings are joined by smooth muscle called trachealis

Question 17

Layers of the Trachea 3

Answer 17

1. respiratory epithelium(mucosa)
2. Lamina propria(tunica fibromusculocartilaginea)
   mixed seromucus glands that humidify air
3. Tunica adventitia

Question 18

terminal bar components

Answer 18

tight junctions
zonula adherenes
desmosomes

Question 19

3 cell types in the mucosa of trachea

Answer 19

1. mucous goblet cell
2. Basal cell-progenitor cells
3. Ciliated columnar cell-push stuff up and out

Question 20

supporting structures of the trachea

Answer 20

C shape hyaline cartilage and trachealis smooth muscle

Question 21

As you descend the lower RT what alterations occur?

Answer 21

1. epithelium height and complexity decreases
2. cartilage rings become irregular plates and then go away at the level of the bronchioles
3. Trachealis muscle is replaced with bundles of smooth muscle (SM) that spiral airways
4. Amount of elastic fibers and SM proportionally increases. Goblet cells and glands decrease

Question 22

3 layers of bronchi

Answer 22

1. mucosa (RE gives to simple ciliated columnar as you go down
2. lamina propria (SM, elastic tissue, C-rings give to plates at level of secondary bronchi)
3. Adventitia (CT)

Question 23

Bronchioles

Answer 23

• ciliated simple cuboidal epithelium with some goblet cells

- NO cartilage

Question 24

Terminal bronchioles

Answer 24

• end of conduction
• Some simple cuboidal ciliated cells
• club cells
• no cartilage, some SM but not much

Question 25

What are club cells in the terminal bronchioles?

Answer 25

club shaped, non ciliated, secretory granules, secret surfactant and antimicrobial peptides, progenitor cell population

Question 26

pathway from terminal bronchiole to alveoli

Answer 26

TB->respiratory bronchiole->alveolar duct->alveolar sac

->alveoli

Question 27

Alveoli

Answer 27

Structural and functional unit of lung
specialized for gas exchange
300 mil/lung
made of simple squamous epithelium

Question 28

Alveoli structure

Answer 28

• thin sacs separated by inter-alveolar septa
• connected by alveolar pores aka pores of Kohn
• these distribute air evenly
• prevent total loss of ventilation
• aid in spread of of bacteria and neoplasms.

Question 29

Alveolar cell types

type I

Answer 29

type I physically make up the very thin membrane for gas exchange
make up most of alveolar surface
joined by tight junctions

Question 30

Alveolar cell types

type II

Answer 30

type II larger cuboidal cells that make surfactant and serve as progenitor cells for tissue renewal

Question 31

Alveolar cell types

Dust cell

Answer 31

these are the Macs of the alveoli