Brainscape's Knowledge GenomeTM

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


See full index

Respiratory System > Resp 5 - Lung cell biology > Flashcards

Resp 5 - Lung cell biology Flashcards

1
Q

The cross sectional area of the lungs increases peripherally. How many generations of gas exchange units are there?

A

23

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

What are the gas exchange units lined with?

A

Surfactant

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

Contrast the function and coverage of type 1 epithelium ad type 2 epithelium of the alveoli.

A

Type 1 - 95% coverage. Surface for gas exchange to occur.

Type 2 - 5% coverage, synthesise and releases lung lining liquid (including lung surfactant - prevents lungs from collapsing at low pressure on exhalation).

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

Name 5 roles of epithelium in the lungs

A
  1. Forms continuous barrier
  2. Secretions which facilitate clearance via mucociliary escalator and protects underlying cells (also maintains low surface tension in alveoli)
  3. Metabolises foreign and host derived compounds
  4. Triggers lung repair processes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How common are goblet cells?

A

Normally 1/5 of epithelial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Mucus is at solution phase overlaying cells. What phase it at the air interface?

A

Thick gel phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What do mucin proteins, GAGs and proteoglycans enable?

A

It enables mucus to have viscoelasticity

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

What does mucus contain (except mucin/gags/proteoglycans)?

A
  1. Albumin and Alpha 1 antitrypsin/alpha 1 proteinase inhibitor - inhibits polymorphonuclear neutrophil proteases. Combats microorganism and phagocyte proteases.
  2. Antiproteases (synthesised by epithelial cells) - combats microorganism and phagocyte proteases
  3. Antioxidants - from blood and epithelial cells. Combats inhaled oxidants and counteracts excessive oxidants released by activated phagocytes.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What happens in smokers to mucus/goblet cells?

A
  1. Goblet cell number doubles
  2. Secretions increase in quantity
  3. Thicker secretions

Gel phase traps cigarette smoke but also traps microorganisms which increases the chance of infection.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Ciliated cells - how frequent are they?

Describe the tips of cilia

A

80% of epithelial cells.

The tips of cilia are in the sol phase of mucus and push mucus towards the epiglottis - mucus usually swallowed/spit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe cilia in smokers

A
  1. Cilia cells depleted severely
  2. Cilia beat asynchronously
  3. Cilia found in bronchioles (despite reduction in airways)
  4. Cilia unable to transport thick mucus - less mucus cleared.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What can reduced mucus clearance lead to in smokers?

A

Respiratory infection and bronchitis.

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

Are the small airways cartilagenous?

A

No

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

What happens to the small airways in COPD?

A
  1. Mucus trapped so narrow airway

2. Mucus broken down by enzymes and inflammatory cells - reduces peripheral gas exchange.

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

What are Clara cells and what is their major role?

A

They are non-ciliated secretory epithelial cells found in large, central and small airways, as well as bronchi and bronchioles. More found in bronchi and bronchioles (they increase proportion distally)

Major role is xenobiotic metabolism - they metabolise foreign material deposited by inhalation.

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

Clara cells contain phase 1 and phase 2 enzymes.

What do Phase 1 enzymes do?
What do Phase 2 enzymes do?

A

Phase 1 enzymes include p450 cytochrome oxidases. They metabolise foreign material into a format that phase 2 enzymes can act on (neutralise toxic agent). They often activate a pre carcinogen though (benzopyrene)

Phase 2 enzymes (e.g. Glutathione S-transferase) enable BPDE to be conjugated to a small molecule, neutralising its activity.

17
Q

What is the pre carcinogen and how is it made into a carcinogen via Phase 1 enzymes?

A

Precarcinogen (benzopyrene) made into benzopyrene diol epoxide (BPDE - carcinogen) through cytochrome oxidases.

If you have Cytochrome P450 oxidase and no glutathione-S-transferase, you are 40x more likely to get lung cancer

18
Q

2 things that Clara cells synthesise and release?

A

Antiproteinases and lysozyme

19
Q

How does smoking affect the alveoli?

A

Increases dead space in the alveoli - holes in alveoli cause alveoli to become larger. This causes a reduction in SA for gas exchange.

May be seen as elastic tissue loss. This causes reduced expansion during breathing.

20
Q

Which type of alveolar epithelial cells are more susceptible to damage?

Which cells are actually damaged more?

A

Type 2 more susceptible to damage.

Type 1 damaged more

21
Q

Describe Type 2 cell structure, function and location

A
  1. Contain lamellar bodies - stores surfactant before release
  2. Synthesises and secretes antiproteinases
  3. Positioned in the corners of the lung. Embedded in the interstitium - apical membranes face the air.
  4. Very close to capillaries.
22
Q

What are Type 2 alveolar epithelial cells a precursor for

A

Precursor for alveolar type 1 epithelial cells - they divide and differentiate to replace damage damaged type 1 cells.

23
Q

Describe surfactant

A

Phospholipid rich surface active material. it prevents lung collapse on expiration and has immunological functions.

24
Q

What 5 things does an alveolar unit consist of?

A
  1. Type 1 cells
  2. Type 2 cells
  3. Stromal fibroblasts
  4. Alveolar macrophages
  5. Capillary endothelium

(There are more type 2 than 1, but 1 covers 95% of the area)

25
Q

What do stromal fibroblasts do?

A
  1. Make ECM
  2. Make collagen and elastin
  3. Divide to repair
26
Q

Give 1 adaptation of capillary endothelium?

A

They are in close proximity to alveolus - reduces diffusion distance

27
Q

Alveolar macrophages - describe their functions and properties.

A
  1. Constitute 70% of total phagocytic cells in a normal lung
  2. They are 5-10x more common in smokers lungs
  3. They are important scavengers - they phagocytose debris and microorganisms
  4. They can recruit other inflammatory cells during an infection/toxic inhalation
  5. Synthesise and secrete proteases
  6. Generate oxidants during phagocytosis - kills pathogens
  7. Generates antioxidants (e.g. Glutathione) - neutralises oxidative molecules that may be inhaled/generated in infection
  8. Contain enzymes that metabolise toxicants.
28
Q

Where are alveolar macrophages more common?

A

In the lower respiratory tract

29
Q

Describe polymorphonuclear neutrophils in the respiratory system

A
  1. Only makes up 5% of lower respiratory tract phagocytes.
  2. Makes about 30% of upper respiratory phagocytes (upto 70% in smokers)
  3. Found in greater numbers in conducting airways.
  4. Increase significantly in smokers.
30
Q

What do polymorphonuclear neutrophils store in high levels in granules?

A

Potent proteases that are released on activation. They also release oxidative molecules e.g. hydroxyl anions
Smokers contain many of the proteases.

31
Q

What are the 3 main structures of lung blood vessels?

A
  1. Muscular
  2. Partially muscular
  3. Nonmuscular
32
Q

Which lobe does emphysema typically affect?

A

Central lobe

33
Q

In normal repair of emphysema, what happens?

A

Type 1 cell death stimulates GF release which increases type 2 cell proliferation/differentiation

34
Q

In abnormal repair of emphysema, what happens?

A

Excess tissue breakdown causing elevated GF release. This causes a fibrotic effect (increase type 2 cells and stromal/fibroblast connective tissue synthesis - irreversible damage)

35
Q

What are the effects of smoking?

A
  1. Blocks proliferation and differentiation of type 2 cells into type 1 cells (also stimulates apoptosis and necrosis of type 1 and 2 cells). Also blocks communication between type 2 cells and fibroblasts which hinders repair
  2. Increases number of macrophages and neutrophils tenfold. Serine proteases and metalloproteases are secreted which can recruit pro-inflammatory mediators and cause alveolar inflammation. Antimicrobial oxidants are released which fragments connective tissue which causes damage (peroxides)
  3. Contains pro carcinogens that are activated by phase 1 enzymes. Smoking overloads the normal pathway of it being metabolised and excreted (metabolised as it becomes water soluble)

Respiratory System (16 decks)

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