Body Systems L19 Notes Flashcards

1
Q

Name the factors effecting pulmonary compliance

A

Ease of lung expansion

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2
Q

Describe how the elasticity of connective tissue of the lungs is measured

A
  • Measure -> Elastic recoil

- Lung volume changes -> pressure change

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3
Q

What is the equation for calculation of compliance?

A
  • Compliance = δV / δP (litres/cm H2O)
    Eg. Patient inhales 500ml air. Intrapleural pressure before insp. = -5cm H2O & -8cm at
    end. Calc. compliance of lungs.
    &raquo_space; δV = 500 ml = 0.5L (0->500)
    &raquo_space; δP = (-8) – (-5) = -8 + 5 = -3cm
    = δ = 3cm
    &raquo_space; Compliance = 0.5 / 3 = 0.1667L/cm H2O
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4
Q

Describe how surface tension is created

A

 Surface tension
- Caused -> Intermolecular forces between mol. of liquid
- Air-fluid interface surface -> fluid
» Under tension -> (similar to stretching thin mem. Eg. Fluid layer between
alveolar cells & air)

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5
Q

What is Laplace’s law?

A
  • Laplace’s Law:
    » Relationship between pressure (P) , Surface Tension (T) & Radius (r) of an
    alveolus (bubble).
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6
Q

What does Laplace’s law state?

A

> > At equilibrium -> Tendency of Incr. pressure expands alveolus
&raquo_space; Balances tendency of surface tension to collapse alveolus

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7
Q

What is the equation for Laplace’s law?

A

> > P = 2T / r

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8
Q

Name a major factor influencing surface tension & describe what effect it has

A
  • Pulmonary Surfactant:
    » Reduces surface tension
    -> Incr. compliance
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9
Q

Describe the role of pulmonary surfactant in reducing surface tension

A

> > Equalises pressure differences between large & small alveoli.
Maintains uniform alveolar size
Tension decreases as alveoli decr. in size
Enables adjustment of alveoli -> rates of inflation & deflation.

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10
Q

How does pulmonary surfactant maintain uniform alveolar size?

A

> > Maintains uniform alveolar size

 - > Higher conc. -> Smaller alveoli 
 - > Lower surface tension helps equalise pressure -> alveoli of different sizes. 
 - > Easier inflation -> Smaller alveoli
 - > Energy required -> Alveolae expansion reduced with incr. no. of breaths.
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11
Q

Name the two factors which cause resistance to breathing

A

Lung volume

Bronchial Smooth muscle

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12
Q

What is airway resistance?

A

 Airway Resistance

 Major non-elastic source -> Gas flow resistance

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13
Q

Describe the effect of air resistance on gas flow

A

 Incr. resistance -> Decr. gas flow

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14
Q

What is airway resistance determined by?

A

 Resistance determined -> radius

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15
Q

Name the influencing factors on the radius of the airway

A

Lung volume

Bronchial Smooth muscle

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16
Q

Describe how lung volume influences airway resistance

A
  • Lung Volume:

|&raquo_space; Dilation -> Bronchi -> Lung expansion

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17
Q

Describe the two ways by which bronchial smooth muscle is influenced in order to influence airway resistance

A

Parasympathetic Nerves

Sympathtic nerves & adrenaline

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18
Q

Describe how the parasympathetic nerves effect the bronchial smooth muscle to influence airway resistance

A
  • Bronchial Smooth Muscle:
    » Parasympathetic Nerves
    -> Bronchoconstriction
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19
Q

Describe how the sympathetic nerves & adrenaline effect the bronchial smooth muscle to influence airway resistance

A

> > Sympathetic Nerves & Adrenaline

-> Bronchodilation

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20
Q

What causes stimulation of bronchodilation by via the sympathetic nervous system & adrenaline?

A

> > Sympathetic Nerves & Adrenaline

       - > Bronchodilation
                - ->> Caused 
                          - > Smoke & Dust irritance
                          - > Histamine (Allergic response)
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21
Q

What is the equation for measuring air resistance?

A

 Measuring Airway Resistance:

- ( FEV1 / FVC ) x 100

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22
Q

What two equational factors influence airway resistance?

A
  • Forced Vital Capacity (FVC)

- Forced Expiratory Volume (FEV1)

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23
Q

What is the forced vital capacity?

A
  • Forced Vital Capacity (FVC)
    » Forceable exhalation
    » Little difference to VC
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24
Q

What is the forced expiratory volume?

A
  • Forced Expiratory Volume (FEV1)

|&raquo_space; Vol. of air expired per second

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25
Q

What is the forced expiratory volume used for?

A

> > Used -> Assess changes in airflow resistance
Eg. Athsmatic patients.
Expressed as & of FVC

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26
Q

What affect does inspiration have on lung volume & intra-pleural pressure?

A

 Incr. Lung vol (ml)

 Decr. Intra-pleural pressure (cm H2O)

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27
Q

What affect does expiration have on lung volume & intra-pleural pressure?

A

 Decr. Lung vol (ml)

 Incr. Intra-pleural pressure (cm H2O)

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28
Q

What kind of shape represents lung volume on a graph?

A
  • Lung volume:

 Positive Bell shaped curve -> Inspiration & Expiration

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29
Q

What is the peak value of lung volume on a graph?

A

> > Peak -> 500ml

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30
Q

What shape does intra-pleural pressure create on a graph?

A
  • Intra-pleural pressure:

 Negative (irregularly-shaped) bell curve -> Inspiration & Expiration

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31
Q

What is the peak value of intra-pleural pressure on a graph?

A

> > Peak -> -8 cm

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32
Q

What shape represents intra-pleural pressure on a graph if no airway resistance present?

A

> > If no airway resistance -> V-shaped graph

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33
Q

What effect does elastic recoil of the lungs have on inspiration & expiration?

A
  • Elastic recoil -> lungs
     Opposes inspiration
     Aids expiration
34
Q

What factors influence the value of airway resistance in the lungs?

A
Forced vital Capacity (FEV)
Forced expiratory volume (FEV1)
Inspiration 
Expiration
Lung Volume 
Intra-pleural pressure
Elastic recoil
Surface tension -> Alveoli
35
Q

Describe neonatal respiratory distress syndrome

A

• Neonatal Respiratory Distress Syndrome:
- Lack of surfactant secretion -> premature babies (28-32wks gestation)
» Reduced compliance
» Alveolar collapse -> Exhalation
» Difficulty -> Lung inflation
- 50% die without rapid treatment

36
Q

What are the methods used to assess lung function?

A

 Breath Sound
 Pulmonary Function Tests
 Spirometer

37
Q

How is breath sound used to assess lung function?

A

 Breath Sound
 Presence -> mucous / fluid
 Absence -> Breathing sounds -> Possible collapsed lung

38
Q

How are pulmonary function tests used to assess lung function?

A

 Pulmonary Function Tests
 Peak Flow meter
» Measures speed of air exhalation

39
Q

What is regularly used to assess lung function of chronic asthmatics?

A

> > Regularly used -> Chronic asthmatics

40
Q

What is a spirometer used for? What units are it’s findings given in?

A

 Spirometer
 Measures lung volumes & capacities
 Findings: (Litres)

41
Q

What does a spirometer measure?

A
>> Inspiratory Reserve Volume (IRV)
   >> Tidal Volume (TV)
   >> Expiratory Reserve Volume (ERV)
   >> Residual Volume (RV)
>> Total Lung Capacity
42
Q

What are the normal Inspiratory Reserve Volume (IRV) values for men & women?

A

> Men -> 3.3

> Women -> 1.9

43
Q

What are the normal Expiratory Reserve Volume (ERV) values for men & women?

A

> Men -> 1.0

> Women -> 0.7

44
Q

What are the normal Residual Volume (RV) values for men & women?

A

> > Residual Volume (RV)
> Men -> 1.2
> Women -> 1.1

45
Q

What are the normal Total Volume Capacity of the lungs (IRV) for men & women?

A

> > Total Lung Capacity
> Men -> 6.0
> Women -> 4.2

46
Q

What is the Tidal volume?

A

• Tidal Volume: (TV)

- Volume of air inhaled / exhaled per breath

47
Q

What is the functional residual capacity?

A

• Functional Residual Capacity:

- Volume of air remaining in lungs after normal, passive inhalation

48
Q

What is the equation for the calculation of the functional residual capacity?

A
  • > > Expiratory Reserve Volume + Residual Volume
49
Q

What is the purpose of the functional residual capacity?

A
  • Helps stabilise composition of alveolar air
50
Q

What value cannot be measured using a spirometer?

A

Functional Residual capacity

51
Q

What is the expiratory reserve volume (IRV)?

A

• Expiratory Reserve Volume: (ERV)

- Volume of air forcibly exhaled following normal tidal volume exhalation

52
Q

What is the inspiratory reserve volume (ERV)?

A

• Inspiratory Reserve Volume: (IRV)

- Volume of air forcibly exhaled following normal tidal volume inhalation

53
Q

What is the residual volume (RV)?

A

• Residual Volume: (RV)

- Volume of air remaining in lungs following max expiration

54
Q

What is the vital capacity (VC)?

A

• Vital Capacity: (VC)

- Maximum volume of air expired after max. inspiratory effort

55
Q

What is the equation for calculation of the vital capacity?

A
  • VC = TV + IRV + ERV
56
Q

What are the normal values of vital capacity (VC) for men & women?

A
  • Normal Values:
    » Men -> 4.8 L
    » Women -> 4.2 L
57
Q

What is the inspiratory capacity (IC) ?

A

• Inspiratory Capacity: (IC)

- Maximum volume of air inspired after normal expiration

58
Q

What is the equation for calculation of the inspiratory capacity (IC)?

A
  • IC = TV + IRV
59
Q

What is the functional residual capacity (FRC)?

A

• Functional Residual Capacity: (FRV)

- Volume of air remaining in lungs following normal tidal expiration

60
Q

What is the equation for calculation of the functional residual capacity (FRC)?

A
  • FRC = RV + ERV
61
Q

What is the total lung capacity (TLC)?

A

• Total Lung Capacity: (TLC)

- Maximum volume of air contained in lungs following maximum inspiratory effort

62
Q

What is the equation for calculation of total lung capacity (TLC)?

A
  • TLC = TV + IRV + ERV + RV
63
Q

What are the normal values of total lung capacity (TLC) in men & women?

A
  • Normal Values:
    » Men -> 6.0 L
    » Women -> 4.2 L
64
Q

What two factors does the respiratory system alter to adapt to varying oxygen demands?

A

Respiratory rate

Tidal volume

65
Q

What is the respiratory rate?

A
  • Respiratory Rate

|&raquo_space; No. of breaths per minute

66
Q

What is the tidal volume?

A
  • Tidal Volume

|&raquo_space; Volume of air inhaled / exhaled per breath

67
Q

What is the pulmonary ventilation rate?

A

• Pulmonary Ventilation Rate:

> > Volume of air inhaled / exhaled per minute

68
Q

What is another term representing the respiratory minute volume?

A

• Pulmonary Ventilation Rate

69
Q

How is the pulmonary ventilation rate / respiratory minute volume calculated?
Give an example of this equation numerically using the standard values found in humans for each component.

A
  • Respiratory Rate x Tidal Volume

|&raquo_space; 0.5 L x 12 /min = 6 L/min

70
Q

What is the normal respiratory rate of adult humans?

A

12-15 breaths per min

71
Q

What is anatomical dead space?

A

> > Anatomical Dead Space
-» Volume of air in conducting passages doesn’t participate in gas exchange
Doesn’t reach alveolar surfaces for gas exchange

72
Q

What volume of air doesn’t reach alveolar exchange surfaces for every 0.5L tidal volume?

A

0.15L

73
Q

What portion of the air in the respiratory system does not participate in gas exchange?

A

Volume of air in conducting passages doesn’t participate in gas exchange

74
Q

What is alveolar ventilation?

A

• Alveolar Ventilation:

- Volume of air reaching alveoli per minute

75
Q

What is the equation for alveolar ventilation? Give a numerical example of this equation using the standard values for each component

A
  • [Respiratory Rate] x [(Tidal Volume) - (Anatomical dead space)]
    » 12 x (0.5 – 0.15) = 4.2 L/min
76
Q

What would produce variants between individuals’ lung measurements?

A

Lung size

77
Q

List the circumstances of an individual which may lead them to have larger lung volumes

A
	Males
	Taller individuals
	Athletes
	Individuals -> Higher Altitudes
	Non-smokers
78
Q

List the circumstances of an individual which may lead them to have smaller lung volumes

A
	Females
	Shorter Individuals
	Non-Athletes
	Individuals -> Lower Altitudes
	Smokers
79
Q

List the factors affecting ease of lung expansion

A

 Elasticity of connective tissue -> Lungs
 Mobility -> Chest wall
 Surface tension

80
Q

What does airway resistance oppose?

A

Elastic tension

81
Q

What are the normal tidal volumes (TV) for men & women?

A

> > Tidal Volume (TV)
> Men -> 0.5 – 4.8
> Women -> 0.5 – 3.1