Lungs

Question 1

Respiratory system is spilt into 2 zones, what are they?

Answer 1

Conducting zone which is at the start of the respiratory system (leads air to gas exchange environment)
Respiratory zone which is deeper in the lungs

Question 2

what is the function of the conducting zone?

Answer 2

Filters, warms and moistens air, which allows for more efficient gas exchange

Question 3

The lungs contain something called the mucoconciliary escalator what does it do?

Answer 3

it traps and removes potential pathogens from the lungs

Question 4

forms of airways defense

Answer 4

Nose - filters air, large particles
Mucus
Cough
immune system

Question 5

What is mucociliary clearance

Answer 5

it defends against inhaled pathogens, with a mucus layer on ciliated epithelium, goblet cells in the CZ secrete mucus which traps pathogens and foreign material.

Question 6

What is the mucociliary escalator

Answer 6

it is a mechanism that moves mucus from the lungs to the mouth with the use of ciliated cells

Question 7

What is cystic fibrosis

Answer 7

A defect in the cystic fibrosis transmembrane regulator (CFTR) gene, it is responsible for chloride transport across the epithelial membrane = loss of airway surface liquid and creates a build-up of thick mucus

Question 8

What is airflow obstruction

Answer 8

it is both bronchoconstriction, mucus hyper secretion

Question 9

the 4 stages to atopic asthma

Answer 9

1. sensitization to allergen (antibody ige generation)
2. Early phase response (Re-exposure, mast cell response)
3. Late phase response (severe response, eosinophil driven)
4. Airway remodelling (chronic inflammation)

Question 10

Sensitization summary

Answer 10

Allergen is internalized by dendritic cells, broken down into peptides which are presented to t cells, t cells produce IL-4 which activates B cells to produce antibodies against allergen

Question 11

Early phase summary

Answer 11

IgE binds to mast cells in lungs, stimulates mast cell degranulation = pro-inflammatory mediators released from granules, these stimulate bronchoconstriction and mucus secretion, and eosinophil recruitment

Question 12

Late phase summary

Answer 12

Eosinophils are responsible for the symptoms associated with late phase asthma, recruited to airways following mast cell activation, Granules release inflammatory mediators which stimulate bronchoconstriction and mucus production

Question 13

Airway Remodelling?

Answer 13

Bronchoconstriciton and mucus secretion are reversible but over time the airway becomes hyper-sensitive and get worse with age

Question 14

What is airway obstruction?

Answer 14

Mucus hypersecretion and airway walls thickening

Question 15

2 categories of asthma treatment

Answer 15

Anti-inflammatory agents and bronchodilators

Question 16

how do B2 agonists help asthma

Answer 16

they block nerve signals

Question 17

How do Methylxanthines help asthma

Answer 17

they inhibit the activity of phosphodiesterase in SMC, which increases cyclic AMP concentration in SMC and causes SMC relaxation

Question 18

4 types of anti- inflammatory agents

Answer 18

1. Corticosteroids
2. Leukotriene antagonists
3. Mast cells degranulation inhibitor
4. Neutralization of IgE

Question 19

Corticosteroids pathway

Answer 19

1. taken up by cells
2. Bind to glucocorticoid receptors in teh cytoplasm
3. Receptor drug complex travels to the nucleus
4. Binds to specific sites in DNA that encode anti-inflammatory proteins
5. Stimulates expression of anti-inflammatory genes

Question 20

the arachidonic acid pathway

Answer 20

AA is turned into 2 types of inflammatory mediators: Leukotrienes and Prostaglandins, leukotrienes antagonists prevent the production of leukotrienes by inhibiting LT receptor activation

Question 21

What do the inflammatory inhibitors Leukotrienes and Prostaglandins do?

Answer 21

Leukotrienes - promote Bronchoconstriction and mucus secretion
Prostaglandins - promote Bronchoconstriction

Question 22

The inhibition of mast cell degranulation does what

Answer 22

stops mast cells from releasing their inflammatory mediators