Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Respiratory System > 6. Lung Cell Biology > Flashcards

6. Lung Cell Biology Flashcards

1
Q

What can the surface area of the lungs be compared to (size)?

A

Tennis court

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How does the cross sectional area of the lungs change across the structure?

A

Increases peripherally

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How many generations are there in the lungs?

A
  • 23 generations

* Each generation bifurcates into the next

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What can the volume of surfactant in the lungs be compared to?

A

One wine glass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the role of the epithelium in the lung?

A
  • Continuous barrier
  • Produce secretions (via mucociliary escalator)
  • Metabolise foreign and host-derived compounds
  • Release mediators
  • Trigger lung repair processes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the 3 main functions of mucus?

A
  • Facilitate clearance
  • Protect underlying cells
  • Maintain reduced surface tension (in alveoli)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What proportion of epithelial cells to goblet cells roughly make up?

A

1/5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How does the phase of mucus change in the airways?

A
  • Thin sol phase overlaying the cells

* Thick gel phase at the air interface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does mucus contain?

A
  • For viscoelasticity: mucin proteins, proteoglycans and glycosaminoglycans
  • Serum-derived proteins: albumin and alpha 1-antitrypsin/alpha 1-proteinase inhibitor (combats microorganisms and phagocyte proteases)
  • Antiproteases: secretory leucoprotease inhibitor (combats microorganism and phagocyte proteases)
  • Antioxidants: uric and ascorbic acid (blood), glutathione (cells)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What happens to goblet cells in smokers?

A
  • Number doubles (hyperplasia)
  • Secretions increase in quantity
  • Thicker secretions (can’t be transported)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the positives and negatives of the modified gel phase in smokers?

A
  • Traps cigarette smoke particles

* Traps and harbours microorgansism => enhancing chances of infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What percentage of epithelial cells are ciliated?

A

80%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Where is mucus pushed towards?

A
  • Epiglottis

* Swallowed or expectorated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What phase is the mucus in at the tips of the cilia?

A

Sol phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How do the ciliated cells change in smokers?

A
  • Severely depleted

* Beat asynchronously

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How far down in the lungs are cilia found?

A

Down to the bronchioles

17
Q

What happens to the small airways in COPD?

A
  • Narrowed
  • Broken down by enzymes and inflammatory cells
  • Trapped mucus
18
Q

What are Clara Cells and where are they found?

A
  • Non-ciliated secretory epithelial cells
  • Found in large, central and small airways, and bronchi and bronchioles
  • Found in most conducting airways
  • Increase proportionally distally
19
Q

What is the main role of Clara Cells?

A

Xenobiotic Metabolism - metabolism of foreign compounds deposited by inhalation

20
Q

What do Phase I and Phase II enzymes do in Clara Cells?

A

Phase I enzymes
• Cytochrome P450 oxidases
• Designed to metabolise foreign compounds so phase II enzymes can react and neutralise the toxic agent
• Unfortunately, (CYPIRA1) can activate a precarcinogen into a carcinogen e.g. benzopyrene (in tar) => benzypyrene-diol-epoxide (BPDE)

Phase II enzymes
• Glutathione S-transferase
• BPDE => small molecule (neutralised)
• Some people don’t have this enzyme - if they also have CYPIRA1 extensive metaboliser gene, 40x more likely to get lung cancer

21
Q

What do Clara Cells synthesise and secrete?

A
  • Phase I and II enzymes
  • Antiproteases
  • Lysozyme
22
Q

What happens to the structure of the alveoli in smokers?

A
  • Holes appear - reduce SA

* Elastic tissue loss - expansion reduced - increased dead space

23
Q

What 2 types of epithelial cells do alveolar walls consist of?

A

Type I
• 95% alveolar surface
• Thin and cover capillaries
• Allow gas exchange

Type II [Pneumocytes]
• 5% alveolar surface
• More susceptible to damage
• Lamellar bodies storing surfactant (phospholipid surface active material)
• Synthesise and secrete antiproteases
• Corners of alveoli
• Embedded in the interstitium with the apical membrane facing the air
• Close to capillaries
• Precursor for Type I cells (replace them when damaged)

24
Q

What does the alveolar unit consist of?

A
  • Type I cells
  • Type II cells
  • Stromal fibroblasts
  • Capillary endothelium
25
Q

What is the role of the stromal fibroblasts?

A
  • Make ECM
  • Make collagen and elastin for compliance and elasticity
  • Divide to repair
26
Q

Describe the role of alveolar macrophages

A
  • 70% of phagocytes in a normal lung (enriched in LRT)
  • Increase 5-10 fold in a smokers lung
  • Phagocytosis and recruits inflammatory cells
  • Synthesise and secrete serin proteases and metalloproteases (can lead to inflammation)
  • Generates oxidants during phagocytosis
  • Generates antioxidants e.g. glutathione to neutralise oxidative molecules (inhaled or generated)
  • Contain enzymes that metabolise toxicants
27
Q

Describe the role of polymorphonuclear neutrophils

A
  • 5% of LRT phagocytes
  • Increase 5-10 fold individually and become up to 30% of total phagocytes in smokers and infection
  • Higher proportion in conducting airways
  • High levels of proteases in granules
  • Release oxidative molecules e.g. hydroxyl anions
28
Q

Outline classic emphysema

A
  • Centrilobular - begins at the centre of the lobule
  • Fibroblasts adjacent to epithelial cells - available for proliferation
  • Infection => chronic damage (Type 1 cell death) => Alveolar Fibrosis
  • Increased Type II cells
  • Communication between Type II cells and fibroblasts determines normal/abnormal repair mechanisms
  • Normal repair - Type I cell death => growth factor release => Type II cell proliferation
  • Abnormal repair - excess tissue breakdown and elevated growth factor release => fibrotic effect (increase Type II cells and connective tissue synthesis in interstitial space) => irreversible damage
29
Q

How does smoking chemically affect the alveolar unit?

A
  • Blocks proliferation and differentiation of Type II into Type I cells - stimulates necrosis instead
  • Blocks communication between Type II cells and fibroblasts
  • Increases number of macrophages and neutrophils
  • Procarcinogens activated by Phase I enzymes - normally made water soluble, metabolised and excreted, but smoking overloads the pathway and may inactivate the enzyme => DNA binding => mutation

Respiratory System (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions