Histology and Embryology

Question 1

What are 5 functions of the respiratory system?

Answer 1

Supplies oxygen to the blood
Removes CO2 from the blood
Speech
Smell
Lung function in BP control

Question 2

The nasal cavity provides an extensive area for what?

Answer 2

Warming, moistening and filtering air

Question 3

What is the roof of the nasal cavity composed of?

Answer 3

Specialised olfactory epithelium

Question 4

What is the initial part of the nasal cavity known as?

Answer 4

The vestibule

Question 5

What is the nasal vestibule lined with?

Answer 5

Keratinised stratified squamous epithelium

Question 6

What happens to the epithelium as you travel further into the nasal cavity?

Answer 6

First, keratin is lost and then further on it turns into respiratory epithelium

Question 7

What is respiratory epithelium?

Answer 7

Pseudostatified ciliated columnar epithelium with goblet cells

Question 8

What are basal cells?

Answer 8

Stem cells

Question 9

Why are basal cells present in respiratory epithelium?

Answer 9

Because this epithelium gets regenerated quickly, about once a week

Question 10

What is underneath the respiratory epithelium?

Answer 10

Lamina propria

Question 11

What is the lamina propria?

Answer 11

Band of connective tissue containing seromucus glands and a rich venous plexus

Question 12

What is the oropharynx and anterior part of the epiglottis lined with?

Answer 12

Non-keratinised stratified squamous epithelium

Question 13

What are the walls of the larynx made up of?

Answer 13

Muscle, cartilage and respiratory epithelium

Question 14

What is the exception in the larynx which is not covered by respiratory epithelium?

Answer 14

Vocal cords and adjacent structures

Question 15

What are the vocal cords covered with instead of respiratory epithelium?

Answer 15

Stratified squamous epithelium

Question 16

What is continuous with the larynx?

Answer 16

Trachea

Question 17

How does the trachea terminate?

Answer 17

By branching into the main bronchi

Question 18

How many cartilages does the trachea have?

Answer 18

15-20

Question 19

The open side of a C shaped tracheal cartilage is spanned by what?

Answer 19

Fibro-elastic tissue and smooth muscle

Question 20

What lines the surface of the trachea?

Answer 20

Mucus

Question 21

What are the effects of smoking on removal of foreign substances from the airway?

Answer 21

First, cilia is lost. Second, respiratory epithelium will be turned into stratified squamous so no mucus can be moved

Question 22

What type of cartilage is found in the trachea?

Answer 22

Hyaline

Question 23

What happens to hyaline cartilage in the bronchi?

Answer 23

Rings are replaced by irregularly shaped plates

Question 24

What allows oxygen supply to the lungs and large airways?

Answer 24

Bronchial blood supply

Question 25

What is the rough diameter of a bronchi?

Answer 25

< 1mm

Question 26

What do bronchioles lack?

Answer 26

Cartilage and glands

Question 27

What happens to the epithelium as you progress down the respiratory tree?

Answer 27

It gets shorter and changes from columnar to cuboidal

Question 28

What are the smallest bronchiole which lack gas exchange function known as?

Answer 28

Terminal bronchioles

Question 29

Terminal bronchioles branch to give what?

Answer 29

Respiratory bronchioles- first part which can perform gas exchange

Question 30

Smooth muscles of the bronchioles respond to what to cause contract and constrict?

Answer 30

Parasympathetic innervation and histamine

Question 31

What are club/clara cells?

Answer 31

Bronchiolar exocrine cells

Question 32

What are the two types of club cells?

Answer 32

Ciliated and non-ciliated

Question 33

What are different roles of club/Clara cells?

Answer 33

Stem cells, detoxification, immune modulation, surfactant production

Question 34

What is another name for alveolar cells?

Answer 34

Pneumocytes

Question 35

What are type 1 alveolar cells?

Answer 35

Simple squamous epithelium that lines 90% of alveolar surface

Question 36

What do type 2 alveolar cells do?

Answer 36

Produce surfactant

Question 37

How is surfactant released and what does it do?

Answer 37

Exocytosis- reduces surface tension to prevent alveoli collapsing

Question 38

Why do premature infants struggle to keep their airways open?

Answer 38

Alveoli haven't developed properly and so surfactant isn't produced

Question 39

What other cell is present in alveoli?

Answer 39

Macrophages

Question 40

What do macrophages in the alveoli do?

Answer 40

Phagocytose inhaled particles which have escaped mucus entrapment and travel up to the pharynx to be swallowed

Question 41

Embryologically, where does the lining of the trachea and bronchial tree come from?

Answer 41

Endoderm

Question 42

Embryologically, where does all other lung tissue come from?

Answer 42

Visceral mesoderm

Question 43

What are two congenital respiratory conditions?

Answer 43

Oesophageal atresia and trachea-oesophageal fistula

Question 44

What is oesophageal atresia?

Answer 44

Oesophagus has a blind ending instead of connecting normally to the stomach

Question 45

What part of lung development occurs in the embryological phase? When is this?

Answer 45

26 days-6 weeks: respiratory diverticulum forms and there is initial branching to give lungs, lobes and segments

Question 46

What stage does the branching of the terminal bronchioles occur? When is this?

Answer 46

Pseudoglandular: 6-16 weeks

Question 47

What happens in the canalicular stage of development? When is this?

Answer 47

16-28 weeks: terminal bronchioles divide to respiratory bronchioles and alveolar ducts

Question 48

In what developmental stage do terminal sacs form and capillaries establish contact? When is this?

Answer 48

28-36 weeks: saccular

Question 49

What stage of development do the alveoli mature? When is this?

Answer 49

Alveolar- 36 weeks-early childhood

Question 50

What does not enough surfactant cause in babies?

Answer 50

Respiratory distress syndrome