Respiration I Flashcards

1
Q

What is laminar flow

A

flow of a fluid when each particle follows a smooth path

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2
Q

What is flow type governed

A

determination of flow type

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3
Q

Describe the alveolar pressure during expiration

A

alveolar pressure is greater than atmospheric pressure

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4
Q

Under laminar conditions what is flow rate proportional to

A

the pressure gradient

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5
Q

Where does maximum rate of flow occur

A

centre of a tube

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6
Q

What is turbulent flow rate proportional to

A

square root of the pressure gradient/difference

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7
Q

TRUE or FALSE - in most places of the lung air flow is laminar

A

FALSE

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8
Q

What do you need to achieve a set flow rate under turbulent conditions

A

greater pressure gradient

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9
Q

Describe the relationship between flow rate and pressure under laminar conditions

A

positive linear correlation

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10
Q

Under what circumstances do eddies develop

A

when turbulent air hits branching points

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11
Q

Describe transitional flow

A

when air becomes turbulent then returns to being laminar

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12
Q

Where is cross sectional area of the airways high

A

respiratory zone

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13
Q

Why does the respiratory zone have high cross sectional area

A

branches

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14
Q

Describe the relationship between velocity and cross sectional area

A

velocity decreases as cross sectional area increases

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15
Q

What is the normal flow type at high velocity

A

turbulent

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16
Q

Name some factors reducing airway diameter

A

inflammation, increased mucous production, oedema

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17
Q

What is COPD

A

progressive lung diseases characterised by increased airway resistance and decreased airflow

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18
Q

Examples of COPD

A

Chronic bronchitis, emphysema

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19
Q

Describe chronic bronchitid

A

long term inflammation of bronchi and bronchioles

20
Q

Describe emphysema

A

destruction of alveoli walls

21
Q

True or False - There is a cure for emphysema

A

false

22
Q

What are gluco-corticosteroids used for

A

reduce background inflammation and maintain decent air flow

23
Q

Why do the airways become floppy in emphysema

A

loss of elastic nature

24
Q

What can be used to manage COPD

A

gluco-corticosteroids, and bronchodilators

25
Q

What are bronchodilators

A

anti-cholinergics or B2 adrenoreceptor agonists

26
Q

Example of beta 2 adrenoreceptor agonist

A

salbutamol

27
Q

What is Poiseuille’s law

A

Airway resistance is proportional to gas viscocity and the length of the tube

28
Q

What is airway resistance inversely proportional to

A

fourth power of the radius

29
Q

What is the difference in airway resistance in COPD

A

huge resistance in small airways compared to normal.

30
Q

What is oedema

A

increased fluid retention in the lungs

31
Q

Describe the pressure in the alveoli at the end of normal respiration

A

same as barometric pressure

32
Q

describe the pressure in the intrapleural space at rest

A

sub atmospheric

33
Q

What happens if alveolar and intrapleural pressure are equal

A

collapsed lung

34
Q

What is transmural pressure

A

difference in pressure between two sides of a wall

35
Q

Where is the maximum pressure gradient in the lungs during inspiration

A

alveoli

36
Q

What is the net effect of the transmural pressure during inspiration

A

airway expansion

37
Q

What is the value of transmural pressure during inspiration

A

positive

38
Q

What is the effect of transmural pressure during inspiration

A

causes airway expansion, therefore decreasing the resistance

39
Q

How can patients with emphysema overcome airway collapse

A

exhale through pursed lips or expire slowly

40
Q

Describe the relationship between lung volume and airway resistance

A

as lung volume increases, airway resistance reduces

41
Q

When is airway resistance highest

A

small lung volume

42
Q

Describe the relationship between resistance and inflation

A

when resistance is increased inflation is impaired

43
Q

Under what time constant do lungs inflate rapidly

A

small time constant

44
Q

What is the time constant under normal conditions

A

low time constant

45
Q

Describe the time constant in COPD

A

increased, lungs dont inflate as quickly