WEEK 4: Basic Histology; Respiratory System

Question 1

2 main functions of histological features of respiratory system include?

Answer 1

air conduction and air modification
external respiration - exchange of gases between air and the blood

Question 2

What are the conduction pathways of the body?

Answer 2

nostrils, pharynx larynx, trachea, bronchi, terminal bronchioles

Question 3

what is external respiration carried out by?

Answer 3

respiratory bronchioles, alveolar ducts, alveoli

Question 4

What is the general layered wall plan to tubes in the airway?

Answer 4

• Mucosa
• Submucosa
  -Adventitia

Question 5

What is the mucosa made up of?

Answer 5

• epithelium
  -basement membrane
  -lamina propria (glands & smooth muscle)

Question 6

What is the submucosa made up of?

Answer 6

Dense connective tissue
Hyaline cartilage & large veins

Question 7

What is the adventitia made up of?

Answer 7

Connective tissue

Question 8

Respiratory mucosa is lined by ?

Answer 8

Respiratory epithelium

Question 9

What is a respiratory epithelium?

Answer 9

It is a pseudostratified columnar with ciliated cells and goblet cells

Question 10

What is the connective tissue under the epithelium called?

Answer 10

Lamina propria

Question 11

What does the connective tissue in the trachea wall contain?

Answer 11

• a lot of seromucous glands
• trachealis smooth muscle
• C shaped hyaline cartilage

Question 12

What is the role of the C shaped hyaline cartilage

Answer 12

To keep the airway patent and enable inflow/outflow of air

Question 13

What are the most easily picked out cell types in the respiratory epithelium

Answer 13

1. ciliated cells
2. goblet cells
3. basal cells (stem cells)

Question 14

What are the less common cells that can be found in the respiratory epithelium?

Answer 14

Brush cells with microvilli
small granule cells

Question 15

What does the lamina propria contain?

Answer 15

Defense cells
Elastic fibres
Seromucous glands
mucosal venules

Question 16

What kind of defense cells are present in the lamina propria?

Answer 16

• macrophages
• lymphocytes
• plasma cells

Question 17

What kind of transition is it from loose to dense connective tissue (lamina propria -> submucosa)

Answer 17

A gradual transition with the presence of smooth muscle/cartilage with no identifiable boundary

Question 18

The loose CT of the lamina propria will be closer to the __

Answer 18

lumen

Question 19

The denser CT of submucosa has deeper location relative to the __

Answer 19

Lumen

Question 20

What is the overarching function of respiratory mucosa

Answer 20

1. secretions from cells within that coat the epithelial surface with sticky viscous film that traps inhaled particles & microorganisms
2. debris that is trapped is moved towards the pharynx via ciliary action
   Overall acting as filtration of air !

Question 21

What other functions can the respiratory mucosa have?

Answer 21

• serous secretions keep viscous coating layer hydrated and humidify air
• heat transfer from mucosal blood vessels warm air
• removal of pathogens

Question 22

What does the removal of pathogens involve?

Answer 22

• immunoglobulins, antiproteases and lysozyme in viscous film disable bacterial functions
• defense cells in lamina propria target and destroy pathogens that cross epithelium

Question 23

cartilage holds larger airways open to maintain ___

Answer 23

Airflow

Question 24

What is the adventitia?

Answer 24

The outermost CT layer of wall that merges into surrounding CT to hold tube in place

Question 25

What are alevoili

Answer 25

Air sacs located deep in lungs at ends of alveolar ducts

Question 26

Adjacent alveoli share walls called?

Answer 26

Interalveolar septae

Question 27

Alveolar walls are lined by simple __ ___

Answer 27

squamous epithelium

Question 28

Centre of the septae contains?

Answer 28

- little smooth musce - a lot of elastic fibres - extensive capillary network

Question 29

what does the alveolar epithelium consist of?

Answer 29

- type 1 alveolar cell/septal cell/pneumocyte - type 2 alveolar cell - other cells including the alveolar macrophage (may sit on top of the epithelium)

Question 30

type 1 alveolar cell is squamous for

Answer 30

exchange

Question 31

function of type 2 alveolar cell is to

Answer 31

secrete sufactant onto surface of alveoli

Question 32

type 2 cells are located at

Answer 32

septal junctions

Question 33

what functions do secretions in type 2 cells have?

Answer 33

- decreased alveolar surface tension - assistance in clearing foreign materials - modulate alveolar immune response

Question 34

what other function do type 2 cells have?

Answer 34

- producing surfactant which are secretory granules that contain phospholipids, neutral lipids and proteins

Question 35

what are alveolar macrophages

Answer 35

cells that start as monocytes that differentiate to become macrophages

Question 36

Alveolar macrophages can migrate into the __ and back to ___

Answer 36

alveoli and septae

Question 37

what do alveolar macrophages do?

Answer 37

scavenge alveolar surfaces to remove particulate matter & remove escaped rbcs from septal CT

Question 38

The connective tissue core of the interalveolar septum contains an extensive ____

Answer 38

pulmonary capillary network that is supplied by pulmonary arteries

Question 39

With increasing proximity to the respiratory exchange surface, the airway walls reduce in __ and __

Answer 39

thickness, complexity