Natalie - Compliance and Elastic Recoil Flashcards

1
Q

What are two other names for the alveolar region of the lung?

A

Acinar region

Parenchymal region

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2
Q

What are the main functions of the alveolar region?

A

Gas exchange

Support

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3
Q

What is the name given to a support tissue?

A

Parenchymal tissue

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4
Q

Give an example of a disease brought on by the lack of alveoli and closed airways

A

Emphysema

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5
Q

What are the alveolar walls also called?

A

The respiratory membrane

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6
Q

Write a note on the alveolar walls
(5)

A

Simple squamous epithelium

Endothelial cells line the capillaries

Fused basal laminae -> alveoli share walls for efficient gas diffusion

Septal cells

Alveolar macrophages - patrol epithelium and engulf foreign particles

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7
Q

Write a note on the simple squamous epithelium found in the alveoli.
(5)

A

Type 1 alveolar cell/type 1 septal cell/type 1 pneumocyte

Provide structure to the wall

Have energy-dependent membrane associated pumps

Important in removal of fluid which could potentially prevent gas exchange

These cells cannot divide when they are damaged or dying

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8
Q

Write a note on type 2 pneumocytes
(5)

A

Pneumocytes
Type 2 alveolar/septal cells

Scattered in respiratory membrane, more rounded than type 1

Produce surfactant - keep alveoli open during breathing and reduce surface tension

Twice as abundant as type 1

Can replace type 1 when they die

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9
Q

What type of cells produce surfactant?

A

Type 2 septal cells/pneumocytes

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10
Q

What are alveolar macrophages also called?

A

Dust cells

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11
Q

What determines the rate at which air flows into and out of the lungs?
(2)

A

The pressure gradient between the atmosphere and alveoli

The airway resistance

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12
Q

Define lung compliance
(2)

A

A measure of the ease at which our lungs can stretch

The change in lunge volume that results from a given change in transpulmonary pressure

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13
Q

What is the equation for lung compliance?

A

Change in lung volume/change in transpulmonary pressure

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14
Q

Why is a large lung compliance advantageous?
(2)

A

Because a smaller change in transpulmonary pressure is needed to bring a given volume of air

Therefore less work/muscle contraction is required

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15
Q

Describe the chest wall in infants

A

Very soft cartilaginous chest wall = very compliant

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16
Q

Describe the chest wall in the elderly
(2)

A

They develop arthritis and chest muscle wasting

This can affect stiffness of chest wall which decreases compliance

17
Q

Describe the chest wall in the diseased

A

Altered compliance because of the effects on the chest wall -> restrictive conditions such as muscular dystrophy can decrease compliance

18
Q

How is compliancy affected by fibrosis?

A

Stiffer lung = less compliant = harder to inhale

19
Q

How is compliancy affected by emphysema?
(3)

A

Alveoli are lost

Lung more compliant on inhalation because the spaces fill quickly

Air can’t get out on exhalation

20
Q

How does elastic recoil compare to lung compliancy?
(2)

A

Compliant = lung can stretch out

Elastic recoil = lung can recoil in and can resist being overstretched

21
Q

Define elastic recoil

A

Lungs ability to return to its resting volume after distension

22
Q

What is responsible for the lungs elastic nature?

A

Elastin nature of tissues (elastin and collagen)

Surface tension in alveoli

23
Q

What gives rise to the surface tension in the alveoli?

A

It arises from liquid molecules lining alveoli (surfactant) having a stronger attraction to each other than to air (made by type 2 pneumocytes)

24
Q

In relation to elastic recoil, how does the alveolus work?
(3)

A

It resists stretching

It recoils back into shape after stretching

It favours reduced surface area

25
Q

The lung and chest wall system is in dynamic equilibrium, what does this mean?
(3)

A

The chest wall expands OUT, the lung recoils IN

The two forces are of equal magnitude but in opposite directions

Therefore they are in dynamic equilibrium

26
Q

What type of disorder is emphysema?

A

Obstructive

27
Q

What happens in emphysema?
(4)

A

Loss of alveoli from lung

Airways become narrowed because alveoli around them collapse - can’t hold airways open (loss of radial traction)

Initially increases compliance but overall leads to reduced compliance because air becomes trapped (cant exhale)

Less alveolar wall = less gas diffusion

28
Q

What is radial traction?

A

How the alveoli hold the airways open