Respiratory System

Question 1

Why do we have so many defense mechanisms for the respiratory system

Answer 1

It is so exposed to the outside world with three big holes on our face

Question 2

What are the paranasal air sinuses

Answer 2

Question 3

Role of hair and mucous in nose

Answer 3

Trapping things that aren’t supposed to be there

Question 4

Epithelia in Respiratory System

Answer 4

Pseudo stratified columnar ciliated epithelium

Same in entire respiratory system (except alveoli)

Question 5

Role of cilia in respiratory system

Answer 5

Beating the mucous which traps dirt and microbes out of the respiratory system to keep it free of such things

Question 6

Components of lower respiratory system

Answer 6

Airways: Progressively smaller tubes ending in blind ending sacs which conduct air to the sites for gaseous exchange and defence mechanisms

Alveoli: Sacs for gaseous exchange - Simple squamous epithelia

Connective tissue: Interstitium

Question 7

Rings aroud trachea and their function

Answer 7

Cartilaginous rings to keep the airway open and give it structural support

They are C-shaped rings; smooth muscle is between the ends of the C

Cartilage is needed specifically in the trachea as SM wouldn’t really keep the airways open properly; a bit of SM at the back to open it and close it; also to protect

Additionallly SM sits against the oesophagus, preventing them from pushing on each other

Question 8

Carina

Answer 8

Question 9

Describe the changes in cartilage as you go through the airway from the trachea to the bronchioles/alveoli

Answer 9

They go from rings, losing cartilage to become plates in bronchi and then disappear in bronchioles; SM increases along the system

Question 10

Describe the change in epithelial type along the airway system

Answer 10

They become more and more squashed/cuboidal and less ciliated. They become completely flat at the alveoli

Question 11

Mucosa of the Lungs

Answer 11

Respiratory Epithelium
Pseudostratified columnar ciliated epithelia (with basement membrane)

Goblet Cells
Produces mucous (part of epithelia i think)

Lamina Propria
Connective tissue, blood and lymph that sits below the epithelia

Question 12

Airway layers of the lung below the mucosa

Answer 12

Thin band of smooth muscle

Submuscosa containing different glands that produce mucous

Question 13

What are the different layers [respiratory tract] (ignore the bottom one)

Answer 13

Top to Bottom:

Respiratory Epithelia
Lamina Propria
(Smooth muscle but its not labelled)
Submucosa

note the cauliflour shaped things are mucous producing glands and purple things are watery producing glands

Question 14

Club Cells

Answer 14

Cells in terminal bronchioles that replace goblet cells and produce less mucous but more surfactant

Question 15

What would poorly functioning cilia cause

Answer 15

Long term respiratory damage

Bronchiectosis

Mucous would build up/clog and lead to coughs and then infection

Question 16

Metaplasia

Answer 16

Change in type of cell
(e.g. as a result of smoking)

Can lead to change in epithelial type and loss of cilia in lungs

Question 17

General trend in variation of cartilage, smooth muscle, glands and cell thickness as airways narrow

Answer 17

Less cartilage, more SM, fewer glands, flatter cells

Question 18

Simply describe what would happen if the airways are clogged up/blocked; think FEV1:FVC

Answer 18

The lung volume wouldn’t change but it would be slower, leading to breathlessness

Question 19

What type of cells are the type I and II pneumocytes

Answer 19

They are the epithelial cells of the alveoli

Question 20

Vaguely, when do type II pneumocytes form during gestation

Answer 20

Quite late in foetal development as their lungs are fluid filled; lack of II pneumocytes are a major killer in premature babies

Need to give steroids to encourage their growth

Question 21

What does lung surfactant do

Answer 21

Enables the lung to open and close as it is a friction free fluid

Think of it like putting dish cleaning soap between two sheets of cling film

Question 22

Alveolar pores

Answer 22

Small pores that link alveoli to one another

Question 23

Are there alveolar macrophages

Answer 23

Yes

Been called dust cells in the past I think

Question 24

Intersititium

Answer 24

Lung connective tissue; consists of the capillaries and connective tissue in between them as well as fibroblasts and macrophages

Think of it as pieces of cotton wool between a bunch of grapes (the grapes being the alveoli)

It is what they expand into

It is very delicate/soft and elastic (elastin dense) that allows alveoli to (relatively) easily expand into them

Question 25

What happens if interstitium is damaged; what is a cause of this

Answer 25

Scar tissue forms which has strong type I collagen

Total lung capacity will be affected as the alveoli will struggle more to expand

A cause is the inhalation of asbestos

Question 26

Lung Defense Mechanisms

Answer 26

Nasal Hair, Mucous on surfaces, Cilia, Saliva (with IgA), replacement of epithelial cells

Cough, sharp-angled airway branching, Ig production

Alveolar macrophages/cytokines/neutrophils