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Flashcards in Histology and Embryology Deck (50):
1

What are 5 functions of the respiratory system?

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

2

The nasal cavity provides an extensive area for what?

Warming, moistening and filtering air

3

What is the roof of the nasal cavity composed of?

Specialised olfactory epithelium

4

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

The vestibule

5

What is the nasal vestibule lined with?

Keratinised stratified squamous epithelium

6

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

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

7

What is respiratory epithelium?

Pseudostatified ciliated columnar epithelium with goblet cells

8

What are basal cells?

Stem cells

9

Why are basal cells present in respiratory epithelium?

Because this epithelium gets regenerated quickly, about once a week

10

What is underneath the respiratory epithelium?

Lamina propria

11

What is the lamina propria?

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

12

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

Non-keratinised stratified squamous epithelium

13

What are the walls of the larynx made up of?

Muscle, cartilage and respiratory epithelium

14

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

Vocal cords and adjacent structures

15

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

Stratified squamous epithelium

16

What is continuous with the larynx?

Trachea

17

How does the trachea terminate?

By branching into the main bronchi

18

How many cartilages does the trachea have?

15-20

19

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

Fibro-elastic tissue and smooth muscle

20

What lines the surface of the trachea?

Mucus

21

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

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

22

What type of cartilage is found in the trachea?

Hyaline

23

What happens to hyaline cartilage in the bronchi?

Rings are replaced by irregularly shaped plates

24

What allows oxygen supply to the lungs and large airways?

Bronchial blood supply

25

What is the rough diameter of a bronchi?

< 1mm

26

What do bronchioles lack?

Cartilage and glands

27

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

It gets shorter and changes from columnar to cuboidal

28

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

Terminal bronchioles

29

Terminal bronchioles branch to give what?

Respiratory bronchioles- first part which can perform gas exchange

30

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

Parasympathetic innervation and histamine

31

What are club/clara cells?

Bronchiolar exocrine cells

32

What are the two types of club cells?

Ciliated and non-ciliated

33

What are different roles of club/Clara cells?

Stem cells, detoxification, immune modulation, surfactant production

34

What is another name for alveolar cells?

Pneumocytes

35

What are type 1 alveolar cells?

Simple squamous epithelium that lines 90% of alveolar surface

36

What do type 2 alveolar cells do?

Produce surfactant

37

How is surfactant released and what does it do?

Exocytosis- reduces surface tension to prevent alveoli collapsing

38

Why do premature infants struggle to keep their airways open?

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

39

What other cell is present in alveoli?

Macrophages

40

What do macrophages in the alveoli do?

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

41

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

Endoderm

42

Embryologically, where does all other lung tissue come from?

Visceral mesoderm

43

What are two congenital respiratory conditions?

Oesophageal atresia and trachea-oesophageal fistula

44

What is oesophageal atresia?

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

45

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

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

46

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

Pseudoglandular: 6-16 weeks

47

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

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

48

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

28-36 weeks: saccular

49

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

Alveolar- 36 weeks-early childhood

50

What does not enough surfactant cause in babies?

Respiratory distress syndrome