Histology of the Respiratory System

Question 1

What are some functions of the respiratory system?

Answer 1

Supplies oxygen to the blood for delivery to cells throughout the body.
Removes carbon dioxide that has been accumulated in the blood from the tissues of the body.
Phonation. (speaking)
Olfaction. (smelling)

Lungs function in blood pressure control via renin-angiotensin system (angiotensin I > angiotensin II via angiotensin-converting enzyme (ACE) in lung capillaries).

Question 2

What does the nasal cavity allow for?

Answer 2

Warming, moistening, filtering of the inspired air

Question 3

What type of epithelium covers the initial nasal cavity?

Answer 3

Keratinised stratified squamous

Question 4

What then lines the rest of the majority of the conducting part of the resp system?

Answer 4

Pseudo-stratified ciliated columnar epithelium with goblet cells (also known as respiratory epithelium)

Question 5

What do the goblet cells do?

Answer 5

Release mucous etc

Question 6

Describe the lining of the nasal cavity underneath the Resp epithelium?

Answer 6

There is the lamina propria - a band of connective tissue which contains seromuscous glands, and also a rich venous plexus which can quickly engorge with blood and therefore block the nose

Question 7

What is the oropharynx lined with and why?

Answer 7

Non-keratinized stratified squamous epithelium as well as most of the epiglottis - as it transmits both air and food so much resist abrasion.

Question 8

What epithelium is the larynx lined with?

Answer 8

Respiratory epithelium

Question 9

What is the vocal folds in the larynx lined with?

Answer 9

Stratified squamous (they are moving all the time)

Question 10

Is stratified squamous epithelium good or bad at producing secretions?

Answer 10

BAD

Question 11

Describe the trachea?

Answer 11

Continuous with the larynx and terminates by diving into bronchi
Contains C shaped cartilages

Question 12

Describe the tracheas lining?

Answer 12

It is lined with resp epithelium

Backed by a basal lamina and a lamina propria which contains loose connective tissue and seromucous glands

Question 13

Describe the change in cartilage when the trachea terminates and further divides into bronchi?

Answer 13

The C shaped hyaline cartilage are replaced by irregularly shaped cartilage plates.

Question 14

Describe how the cells of the wall of the conducting airways obtain O2 and nutrients etc?

Answer 14

There is a very small secondary blood supply to the lungs that enter with the bronchi (bronchiole arteries)

Question 15

Do bronchioles contain cartilage?

Answer 15

NO

Question 16

What does the terminal bronchioles give rise to?

Answer 16

Respiratory bronchioles - the first part of the tree that has respiratory function

Question 17

What type of innervation do the smooth muscle of the bronchioles respond to?

Answer 17

Parasympathetic

Question 18

What type os epithelium lines terminal bronchioles?

Answer 18

Cuboidal epithelium - include ciliated cells and non-ciliated club cells

Question 19

What are Club cells?

Answer 19

Also known as clara cells - functions = stem cells, detoxification, immune modulation, surfactant production

Question 20

Describe type 1 alveolar cells?

Answer 20

Simple squamous epithelium that lines the alveolar surfaces, provide a barrier and allow gas exchange

Question 21

Describe type 2 alveolar cells?

Answer 21

Covered in microvilli, contain and secret surfactant which reduces the surface tension .

Question 22

Where does the conduction portion of the resp system end and the respiratory portion start?

Answer 22

Ends at the terminal bronchiole, and starts at the respiratory bronchiole

Question 23

Describe alveoli?

Answer 23

Lined by an epithelium that consist of type 1 and type 2 alveolar cells.

Question 24

Describe alveolar macrophages?

Answer 24

Also known as dust cell.
Usually migrating over the surfaces of alveoli, phagocytose any inhaled particles that have reached the alveoli, migrate the particles up to the pharynx where they are swallowed.

Question 25

What type of cells does the air-blood barrier contain?

Answer 25

Type 1 cells.