Lecture 5: Respiratory Histology

Question 1

What is the function of the conduction portion of the lungs?

Answer 1

Warms and filters air passing through

-no gas exchange!

Question 2

What portions of the respiratory tract compose the conduction portion of the lungs?

Answer 2

Nasal Cavity to Terminal Bronchioles

Question 3

What is the function of the respiratory portion of the lungs?

Answer 3

Pass air to alveoli for gas exchange

Question 4

What portions of the respiratory tract compose the respiratory portion of the lungs?

Answer 4

Respiratory Bronchioles to Alveolar sacs

Question 5

The wall of the larynx is reinforced by what types of cartilage?

Answer 5

Hyaline and small elastic cartilage

Question 6

What type of epithelium is found in true vocal folds?

Answer 6

Non-keratinized stratified squamous epithelium

-protects mucosa from abrasions

Question 7

What type of epithelium is respiratory epithelium?

Answer 7

Pseudostratified ciliated columnar epithelium

Question 8

What is the function of respiratory epithelium?

Answer 8

Protect airway via mucus production

Transport mucus out of tract via cilia

Question 9

What type of cells are found in respiratory epithelium?

Answer 9

Ciliated cells
Goblet cells: secrete and synthesize mucus
Basal cells

Question 10

What are the four layers of the trachea?

Answer 10

1) Mucosa: Respiratory epithelium w/ elastic lamina propria
2) Submucosa: dense CT
3) Cartilaginous: c-shaped hyaline cartilage rings
4) Adventitia: CT that binds trachea to adjacent structure - trachealis muscle

Question 11

What are some defining histological features of bronchi?

Answer 11

Cells short in height
Fewer goblet cells
Increased elastic fibers 
Full cartilage rings and plates
Loose/areolar CT

Question 12

What are some defining histological features of bronchioles?

Answer 12

Transition b/t simple ciliated columnar to simple cuboidal
Few goblet cells
Increased elastic fibers
No submucosa
NO CARTILAGE

Question 13

What are club cells?

Answer 13

Cells found in terminal bronchioles

• prevent luminal adhesion w/ airway collapse during expiration
• detoxifies inhaled materials
• secretes antimicrobial peptides

Question 14

What do respiratory bronchioles branch into?

Answer 14

Alveolar ducts –> alveolar sacs –> alveoli

Question 15

What are some defining histological features of respiratory bronchioles?

Answer 15

Simple cuboidal
Club cells
Elastic fibers

Question 16

What type of epithelium is found in alveolar ducts, rings, and sacs?

Answer 16

Simple squamous epithelium

Question 17

What are alveolar rings?

Answer 17

Aggregates of smooth muscle, collagen, and elastic fibers that surround alveolar ducts

Question 18

What lines alveoli sacs?

Answer 18

Type I and Type II Pneumocytes

Question 19

What type of epithelium is found in pneumocytes?

Answer 19

Simple squamous epithelium

Question 20

What is the function of Type I pneumocytes?

Answer 20

Surface for gas exchange

Question 21

What is the function of Type II pneumocytes?

Answer 21

Secrete surfactant to reduce surface tension w/in alveoli to prevent collapse during respiration

Question 22

What is the precursor for Type I and Type II pneumocytes?

Answer 22

Type II Pneumocytes

Question 23

Type I pneumocytes are ____ shaped/

Type II Pneumocytes are _____ shaped.

Answer 23

Type I Pneumocytes: Squamous (flat)

Type II Pneumocytes: Cuboidal/round

Question 24

What fluid is found in the pleural cavity?

Answer 24

Serous fluid

Question 25

What covers the pleura?

Answer 25

Mesothelium

Question 26

Describe the blood-air barrier.

Answer 26

Barrier that oxygen and CO2 have to cross in order for gas exchange to occur

Question 27

What are the components of the blood-air barrier?

Answer 27

1) Type I Pneumocytes
2) Fused basal laminae
3) Capillary endothelial cells

Question 28

Describe the physiology of asthma.

Answer 28

• Sudden constriction of smooth muscle in bronchioles

- Infiltration by eosinophils, lymphocytes, and mast cells

Question 29

Describe the physiology of emphysema.

Answer 29

Permanent enlargement of air spaces distal to terminal bronchiole

• significant loss of gas exchange due to decreased SA
• destruction of alveolar walls

Question 30

Describe the physiology of pneumonia.

Answer 30

Inflammation of lung tissue

• air spaces filled with WBC, RBC, and fibrin
• enlarged capillaries
• fewer air spaces