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Medsci 142 > Respiratory > Flashcards

Respiratory Flashcards

1
Q

Define cellular resipration

A

The process through which cells create ATP by breaking down glucose in the presence of oxygen

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2
Q

Define internal (tissue) respiration

A

The process of gas exchange between blood in systemic capillaries and the tissue fluid and cells which surround them

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3
Q

Define external respiration

A

the process where oxygen is absorbed from the atmosphere into blood within the oukmonary capillaries, and carbond dioxide is excreted

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4
Q

What are the nasal conchae responsible for?

A

humidifying, filterning and warming the air

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5
Q

What are the ciliated epithelium responsible for?

A

filtering the air

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6
Q

What are the vibrissae responsible for?

A

filtering the air

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7
Q

What are the secretion of the goblet cells responsible for?

A

humidifying the air

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8
Q

What is th rich blood supply responsible for?

A

warming the air

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9
Q

What are the secretion sof the seromucous glands responsible for?

A

filtering the air

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10
Q

During swallowing, food mus pass through what structure to enter the oesophagus?

A

oropharynx

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11
Q

Label the airways in the diagram (CCA1)

A

trachea - main stem bronchus - loabr bronchi - segmental bronchi - smaller bronchus - bronchiole - terminal bronchioles - respiratory bronchiole - alveolar duct - aleveolus - alveolar sac

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12
Q

Label the diagram of a bronchus (CCA1)

A

goblet cell - pseudostratified ciliated columnar epithelium - smooth muscle - mucous/seromucous gland - cartilage - alveoli

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13
Q

What types of secreting cells do bronchus have vs bronchioles?

A

goblet cells in bronchus, club cells in bronchiole

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14
Q

What type of epithelium is found in the bronchus vs bronchioles

A

pseudostratfied ciliated columanr epithelium in the bronchus vs. simple columnar/cuboidal ciliated epithelium in the bronchiole

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15
Q

what structure in the repsiratory system contains cartilage?

A

traches, bronchus (cartilage plates, c shaped)

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16
Q

Which structure between bronchus and bronchioles contains relatively more smooth muscle?

A

bronchiole

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17
Q

Which structure between bronchus and bronchile contains mucous glands?

A

bronchus

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18
Q

What type of airway is most drmatically affected during an asthma attack?

A

bronchiole - smooth muscle constrict

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19
Q

State the types of cells found within the alveolus

A

Type 1 pneumatocytes, red blood cells, alveolar macrophages, capillary endothelial cells, Type 2 pneumatocytes/surfactant

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20
Q

What is the role of alveolar macrophages?

A

phagocytose and remoce dust and other particles

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21
Q

What do type 2 pneumatocytes secrete? What is the purpose of this secretion?

A

surfactant - reduces surface tension, preventing alveolar collapse

(Increased surface tension increases cohesion within the alveoli, pulling the alveoli closed. surfactant decreases the surface tension in the airways reducing the amount of energy required to expand the lungs)

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22
Q

Indicate the order of layers that an oxygen molecule must pass through to reach a red blood cell, starting in the lumen of the alevoulus

A
  1. lumen of alveolus
  2. Type 1 pneumatocyte cytoplasm (squamous pneumatocyte)
  3. fused basement membrane of Type 1 aleveolar cell and endothelial cell (capillary end)
  4. cytoplasm of capillary endothelium
  5. blood plasma
  6. red blood cell
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23
Q

How thick is the diffusion barrier?

A

0.5 µm

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24
Q

Why are the right and left lungs slightly different in size and shape?

A

to accomodate the heart

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25
Q

How many lobes are in each lung?

A

3 in the right, 2 in the left

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26
Q

Each lobe is supplied with a ____ bronchi

A

secondary

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27
Q

During quiet breathing, inspiration is produced by the contraction of the _____

A

external intercostal muscles

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28
Q

The external intercostal muscles moves the ribcage ____ during inspiration

A

upward and outward

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29
Q

Explain the mechanism of quiet breathing during inspiration and expiration

A

during quiet breathing, inspiration is produced by the contraction of the external intercostal muscles which moves the ribcage upwards, and outwards and the contraction of the diaphragm. Both these mechanisms increase the volume of the thoracic cavity.

Expiration is passive during quiet breathing, but during active/forceful expiration (eg. exercise) the interal intercostal muscles are engaged

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30
Q

The diaphragm is innervated by which nerve? Where does this nerve arise form?

A

phrenic nerve, C3-C5 levels of the spinal cord

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31
Q

The intercostal muscles are innervated by which nerve? where does this nerve originate from?

A

intercostal nerve, T1-L1 levels of the spinal cord

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32
Q

The rectus absominus is innervated by what nerve? Where does this nerve arise from?

A

abdominal nerve, T7-L1 level of the spinal cord

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33
Q

What is the approximate dead space volume in a 70 kg healhy subject?

A

approx. 150 mL

approx. 2.2 ml per kg

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34
Q

Draw out the intrapleural pressure curve

A

//

intrapleural pressure is always negative physiologically.

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35
Q

Draw out the alveolar pressure cuve

A

//

alveolar p. can be both positive (expiration) and negative (inspiration)

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36
Q

What is the unit for air flow?

A

L/s (or Ls-1)

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37
Q

Define peak flow

A

measurement of how quickly you can blow air out of your lungs.

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38
Q

What happens to the intrapulmonary pressure during inhalation?

A

pressure decreases - a negative intrapulmonary pressure (pressure within the respiratory tract) is required to cause air from the outside to move in

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39
Q

What happens to pleural pressure during inhalation?

A

Pressure increases - The pleural pressure becomes more negative during inhalation.

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40
Q

How does the diaphragm move during inhalation?

A

downwards - increasing the volume of the thoracic cavity

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41
Q

During a lecture on Respiratory Physiology, Joe Student fell asleep and slumped forward, impaling himself on the sharp end of his pencil, which penetrated his chest wall between the 4th and 5th ribs. (remember atmospheric pressure is = 760 mmHg)

The pencil penetrated the?

A

Internal intercostals and External intercostals

These are the two muscles that are found in the chest wall in between the ribs (intercostal space)

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42
Q

During a lecture on Respiratory Physiology, Joe Student fell asleep and slumped forward, impaling himself on the sharp end of his pencil, which penetrated his chest wall between the 4th and 5th ribs. (remember atmospheric pressure is = 760 mmHg)

In order to cause a pneumothorax, the pencil would have had to have penetrated at minimum the

A

parietal pleura - As soon as the pencil penetrates this layer, air from outside is able to rush into the intra-pleural space. The resulting loss in negative pressure will cause the lungs to collapse: pneumothorax.

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43
Q

During a lecture on Respiratory Physiology, Joe Student fell asleep and slumped forward, impaling himself on the sharp end of his pencil, which penetrated his chest wall between the 4th and 5th ribs. (remember atmospheric pressure is = 760 mmHg)

Prior to the accident, the pressure in the intrapleural space would have been approximately:

A

755 mmHg - Normally, the intraplural pressure is approximately 5 mmHg below atmospheric pressure (negative pressure relative to atmosphere)

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44
Q

During a lecture on Respiratory Physiology, Joe Student fell asleep and slumped forward, impaling himself on the sharp end of his pencil, which penetrated his chest wall between the 4th and 5th ribs. (remember atmospheric pressure is = 760 mmHg)

If a pneumothorax had occurred, then the volume of the affected lung would have approximated that of:

A

Minimal volume

This volume consists of pockets of air trapped downstream of collapsed airways in the deflated lung. Minimal volume is less than residual volume as the lung has collapsed.

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45
Q

During a lecture on Respiratory Physiology, Joe Student fell asleep and slumped forward, impaling himself on the sharp end of his pencil, which penetrated his chest wall between the 4th and 5th ribs. (remember atmospheric pressure is = 760 mmHg)

If a pneumothorax had occurred, then (to a first approximation) the volume of the unaffected lung would have:

A

Remained unchanged

The left and right pleural cavities are not connected. The unaffected lung functions normally.

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46
Q

During a lecture on Respiratory Physiology, Joe Student fell asleep and slumped forward, impaling himself on the sharp end of his pencil, which penetrated his chest wall between the 4th and 5th ribs. (remember atmospheric pressure is = 760 mmHg)

What would you expect the pleural pressure to be after a pneumothorax?

A

0 cm H2O

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47
Q

How do we measure residual volume?

A

Using a helium dilution method - Using a helium dilution method, you can measure total lung capacity. You can then subtract vital capacity to calculate residual volume.

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48
Q

Label a normal spirograph

A

tidal volume
inpsiratory reserve volume
expiratory reserve volume
residual volume
inspiratory capacity (IRV + TV)
functional residual capacity (ERV + RV)
vital capacity (IC + ERV)
total lung capacity (VC + RV)

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49
Q

What is the difference between respiration and ventilation?

A

respiration - transfer of gases
ventilation - breaths/minute

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50
Q

What are the three types of respiration

A

external respiration, internal respiration, cellular respiration

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51
Q

define pulmonary ventilation?

A

describes the bulk movement of air into and out of the lungs. The ventilatory pump comprises the rib cage with its associated muslces and the diaphragm

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52
Q

What is the structural compositon of the conducting part of the respiratory system?

A

cavities and thick walled tubes which conduct air between the nose and the deepest recesses of the lungs

the nasal cavity, pharynx, trachea, bronchi, and most bronchioles.

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53
Q

What is the function of the conducting part of the respiratory system?

A

conduct air and warm, humidify and clean it.

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54
Q

What are the conducting airways?

A

nasal cavities, pharynx, larynx, trachea, bronchi and bronchioles

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55
Q

What is the structural compositon of the respiratory part of the respiratory system?

A

tiny, thin-walled airways

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56
Q

What happens at the respiratory part of the system?

A

where gases are exchanged between air and blood

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57
Q

What are the airways?

A

respiratory bronchioles, alveolar ducts and sacs and the alveoli themselves

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58
Q

What is the ventilatory pump?

A

movement and muscles that aid in the pressures and volumes that allow air to flow in

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59
Q

Describe the movement of O2 and CO2 in the body

A

O2 in through ventilatory pump - external respiration - left cardiac pump - internal respiration - cellular respiration within cells (gas exchange) - right cardiac pump - ventilatory pump out CO2

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60
Q

Where does external respiration occur?

A

in the blood

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61
Q

What are the three conditioning parameters for air to enter the lungs?

A

warmed to 37°
humidifies (100% saturatewd with H2O)
cleaned

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62
Q

Describe the structure of the nasal cavity

A

tall, narrow chamber lined with mucous membrane. The wet membrane humidifies and warms inspired air

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63
Q

Describe the medial and lateral surface of the nasal cavity

A

the medial surface is flat, the lateral surface carries three sloping chelves (conchae) which increase the surface area of the mucous membrane

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64
Q

What structure opens into the nasal cavity?

A

air filled (paranasal) sinuses

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65
Q

What is the function of the sinuses?

A

they lighten the face and add resonance to the voice

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66
Q

Describe the structure and function of the roof of the nasal cavity

A

carries olfacotry epithelium. Turbulence caused by sniffing carries air up to the epithelium. Axons of olfactory receptor cells lead towards the brain through perforations in the overlaying bone, the cribiform plate

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67
Q

Describe the mucous membrane structure and related function

A

ciliated epithelium, mucus cells (goblet cells), underneath lining - more mucous glands and lots of blood vessles (heat exchange efficiently)

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68
Q

What is the function of the vibrissae

A

first defence for filtering, helps with cleaning

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69
Q

What does the conchae do to the movement of air? What is the significance of this?

A

slows, turbulence - causes particles to be thrown on sticky layer

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70
Q

What are the three parts of the pharynx?

A

nasopharynx (opens anteriorly to nasal cavity)
oropharynx (opens anteriorly to oral cavity)
laryngopharynx (opens anteriorly to larynx)

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71
Q

Describe the anatomical position of the trachea and oesophagus

A

trachea is anterior to the oesophagus

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72
Q

What is the function of the epiglottis?

A

closes - prevents food from entering the glotis/trachea

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73
Q

What is the pattern of branching of the airways?

A

conducting zone (no gas exchange)
trachea
main stem bronchi
lobar bronchi
segmental bronchi
smaller bronchi
bronchioles
terminal bronchioles

respiratory tone (gas exchange)
respiratory bronchioles
alveolar ducts
alveolar sacs

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74
Q

How much branching is there in the main stem bronchi?

A

1

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75
Q

How much branching is there in the lobar bronchi?

A

2

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76
Q

How much branching is there in the segmental bronchi?

A

3

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77
Q

How much branching is there in the snaller bronchi?

A

4-9

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78
Q

How much branching is there in the bronchioles?

A

10-15

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79
Q

How much branching is there in the terminal bronchioles?

A

16-19

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80
Q

How much branching is there in the respiratory bronchioles

A

20-23

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81
Q

How much branching is there in the alveolar ducts

A

24-27

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82
Q

How much branching is there in the alveolar sacs

A

28

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83
Q

how long is the trachea? How thick is it?

A

12 cm, diameter of a thumb

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84
Q

Describe the structure of the trachea

A
  • incomplete C-shaped cartilage rings, free ends of the cartilage are connected by trachealis muscle of which contraction narrows the diamter
  • lined with pseudostratifies columnar ciliated epithelium. cilia transport a mucous sheet upwards to the nasopharynx
    “mucociliary escalator”
  • oesophagzs sits immediately posterior tot he trachea, lying in the shallow groove of the trachealis muscle
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85
Q

Why is cartilage so imperative to the function of the trachea?

A

without it, the trachea would collapse. it is the only pathway for air to enter the lungs

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86
Q

Does the bronchus contain cartilage?

A

yes - irregular plates

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87
Q

Describe the structure of the wall of a bronchus

A
  1. layer of mucus
  2. pseudostratified columnar ciliated epithelium
  3. goblet cells dispersed between (2nd source of mucous)
  4. smooth muscle (controls tone)
  5. mucous glands
  6. cartilage plates
  7. alveoli
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88
Q

What is the difference between bronchus and bronchiole

A

bronchi (bronchus) - conducting, warming, and cleaning the air in the respiratory passageway
bronchioles - conduction of air and gas exchange

bronchioels also do not contain cartilage or mucous glands or goblet cells. These are not necessary because air is cleared in conducting regions before

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89
Q

Describe the structure of the wall of a bronchiole

A
  1. club cell secretion
  2. ciliated cuboidal cells
  3. club cells located between (secrete watery secretion)
  4. smooth muscle
  5. alveoli
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89
Q

Describe the structure of the wall of a bronchiole

A
  1. club cell secretion
  2. ciliated cuboidal cells
  3. club cells located between (secrete watery secretion)
  4. smooth muscle
  5. alveoli
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90
Q

When are cells ciliated

A

always unless in respiratory zone

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91
Q

Explain what happens during an asthma attack

A

bronchoconstriction of smooth muscle - restricts air flow to alveoli - bronchodilator - salbutamol relaxes msucle

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92
Q

What is the bronchiole key function?

A

control of airflow by smooth muscle

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93
Q

Describe what is meant by the mucociliary escalator

A

inside of the conducting airways
mucus and cilia
moves the mucus up and out of the lungs where it can be expelled by coughing or swallowing

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94
Q

Where do mucous glands terminate?

A

smallest bronchi

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95
Q

What are primary, secondary and tertiary bronchi

A

primary - right and left mainstem bronchi supplying each lung
secondary - lobar bronchi supplying lobes (2L, 3R)
tertiary - segmental bronchi supplying segments of the lungs (8L, 10R) - each segment has its own blood and air supply

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96
Q

list the order of pleura

A

visceral pleura, pleural space (serous fluid), parietal pleura, skeletal muscle of ribs or diaphragm

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97
Q

Why is surface tension so important?

A

as surface tension allows adhesion between all layers. It is key in moving the ribcage and diaphragm

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98
Q

Describe how Boyles law is related to ventilation

A

Breathe in - increase the volume of thorax, then we reduce the pressure to allow air to flow in
Breathe out - decrease the volume fo the thorax, then we increase the pressure to let the air out

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99
Q

movement of the ribcage is responsible for _ % of air movement in and out of the lungs

A

25%

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100
Q

Describe the movement of the ribs during inspiration

A

the ribs pivot aorund their joints with the vertebral column, the orientation of the external intercostal muscles means that contraction has the effect of lifting the ribs (rotating them around their pivot points)

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101
Q

Describe the movement of the ribs during expiration

A

The internal intercostal muscles run at angles to the externals. When they contract they drag the ribs downwards. Active contraction only occurs during forceful exhalation

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102
Q

The diaphargm makes up to ___ of the thorax and the ___ of the abdomen

A

floor of the thorax and roof of the abdomen

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103
Q

What is the anatomical composition of the diaphragm?

A

muscular portions at the lateral margins and central tendon (connective tissue) in the middle which acts as attachment to the pleura

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104
Q

What does contraction of the diaphragmatic muscle do?

A

flattens the diaphragm, pulling its central dome downwards, increasing the volume of the thorax and causes inspiration

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105
Q

Movement of the diaphragm is responsible for ___ % of bulk flow of air during quiet breathing

A

75%

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106
Q

when is the abdominal motor neuron recruited?

A

during forced expiration eg. exercise
it allows you to force air out of the lung more quickly to allow you to take your new breath earlier

(coughing, sneezing, straining, laughinh, vocalisation)

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107
Q

What volume of air do we inspire at rest?

A

0.5 L

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108
Q

How does passive expiration work?

A

elastic recoil

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109
Q

What structure of the lungs undergoes changes in pressure relative to pressure inside the lungs?

A

pleural cavity

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110
Q

What causes the movement of air into and out of the lungs?

A

changes in pressure

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111
Q

What happens to pulmonary pressure during inspiration?

A

decreases

during inspiration, the diaphragm contracts and the volume of the lungs increases. Boyles law - increase in volume is decrease in pressure. the decrease in pressure allows air to flow into the lungs

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112
Q

What happens to pulmonary pressure during expiration?

A

increases

volume decreases - boyles law - pressure increases

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113
Q

what is meant by pleural pressure?

A

the pressure surrounding the lung, within the pleural space

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114
Q

The movement of lungs depends on the pressure gradient between ___ (i.e ___, the difference between intra pulmonary pressure and intra pleural pressure).

A

lungs and pleura
transpulmonary pressure

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115
Q

Explain what happens to intrapleural pressure during inspiration and expiration

A

inspiration - becomes more negative drawing air into the lungs
expiration - becomes less negative, causing air to leave the lungs

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116
Q

What is pulmonary pressure at rest?

A

0 mmHg

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117
Q

what is intrapleural pressure at rest?

A

-4 mmHg

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118
Q

Why is intrapleural pressure negative at rest?

A

provides a transpulmonary pressure, causing the lungs to expand.
Negative Ppl helps keep the lungs from collapsing and “adheres” them to the chest wall. - suction

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119
Q

What is a pneumothorax?

A

collapsed lung

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120
Q

What happens during a pneumothorax?

A

air rushes into the chest - loss of negative intrapleural pressure - collapsed lung - unable to inspire

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121
Q

Define Inspiratory reserve volume

A

how much capacity you have within your system that you can increase. i.e how much air you can breathe in that is greater than your nomral tidal breath at rest

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122
Q

what is a normal tidal volume?

A

0.5 l

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123
Q

What is expiratory reserve volume?

A

how much capacity you have within your system that you can dencrease. i.e how much air you can breathe out that is lower than your nomral tidal breath at rest

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124
Q

define functional residual capacity

A

Functional residual capacity (FRC), is the volume remaining in the lungs after a normal, passive exhalation.

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125
Q

define residual volume

A

RV is the amount of air that cannot be expelled from the lungs at the end of a forced expiration.

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126
Q

What lungs volumes is a spirometer able to measure?

A

Tidal breath
respiratory frequency
minute ventilation
IRV
ERV

127
Q

What is minute ventilation?

A

measurement of the amount of air that enters the lungs per minute.

128
Q

How is minute ventilation calculated?

A

Minute ventilation = tidal volume x respiratory frequency

Tidal volume = alveolar ventilation + dead space
Respiratory frequency = how many breaths taken in ine minute

129
Q

What is a normal value for minute ventilation?

A

6 L/min

130
Q

What is alveolar ventilation?

A

amount of ventilation at alveoli, how much air is going into the lungs for ventilation

131
Q

What is the equation for alveolar ventilation?

A

Va = (Ve - Vd) x f

Ve - minute ventilation
Vd- dead space
f - frequency

132
Q

What. is the approximate dead space volume?

A

approx 150 ml

133
Q

What is the general alveolar ventilation volume? i,.e the volume for gas exchange

A

4.2 L/min

134
Q

How is residual volume calculated?

A

measured using an inert gas such as helium

135
Q

What is the purpose of residual volume?

A

The residual volume functions to maintain the patency of alveoli even after maximal forced expiration.

136
Q

What is the equation to measure residual volume?

A

TLC (v1(C1-C2)/C2) - vital capacity

137
Q

Define forced expiratory volume

A

Forced expiratory volume (FEV) measures how much air a person can exhale during a forced breath.

138
Q

What is forced vital capacity?

A

Forced vital capacity the maximum amount of air you can forcibly exhale from your lungs after fully inhaling

139
Q

What. isthe normal FEV1 in a healthy lung?

A

4.0 L

140
Q

What is the normal FEV1/FVC ratio? What does a lower value indicate?

A

80%

a lower measured value corresponds to a more severe lung abnormality.

141
Q

recoil force is split into two subdivisions. What are these?

A

elasticity and surface tension

142
Q

Where does surface tension exit within the lung?

A

at the liquid gas interface in the alveoli

143
Q

What causes surface tension?

A

cohesive forces between the molecules and liquid

144
Q

How is surface tension calculated?

A

measure surface tension induced pressure using La Places Law

Pa = 2x surface tension / alveolar radius

smaller radius casues greater deflating pressure
Pa is pressure within

145
Q

What is lung compliance?

A

measure of the lungs expandability
inversely proportional to elasticity

146
Q

How is compliance measured?

A

change in volume/change in pressure

147
Q

If complience is decreased what happens to pressure

A

Decreased compliance causes the lung to go stiff therefore
pressure must increase to inflate the lung

148
Q

What does COPD do to lung compliance

A

increased lung compliance caused by smoking

149
Q

What are the two factors affecting compliance

A
  1. elasticity from the elastin in connective tissue
  2. surface tension which is decreased by surfactant production.
150
Q

What is the purpose of compliance?

A

allows the lungs to achieve appropriate functional residual capacity, the volume remaining after passive expiration

151
Q

how does surfactant lower surface tension at the alveoli?

A
  • Surfactant binds to water molecules at the air-fluid interface lining the alveoli
  • interfering with and reducing the inter-molecular cohesive forces between water molecules.
  • This reduces the internal pressure or ‘collapsing pressure’ exerted on the alveoli
  • easier to inflate
  • This increases lung compliance.
152
Q

True / False
If a small change of pressure brings about a large change of volume, then compliance is high.

A

True

153
Q

True / False
If a small change of pressure brings about a large change of volume, then the elasticity of the lung is low.

A

True

compliance and elasticity are inversely proprotional

154
Q

What are the main factors that influence lung recoil force during passive expiration?

A

elastic recoil and surfactant (surface tenstion)

155
Q

What does the funnel effect refer to?

A

The funnel effect refers to the increase in cross-sectional area of airways in the lungs towards the base. This increased cross-sectional area makes the air flow slower and less turbulent due to a lesser resistance

156
Q

What is radial traction?

A

elastic and collagen that pull on the walls of the alveoli and keeps them open and decreases resistance to air flow

157
Q

Parasympathetic nerve fibres travelling within the ____ nerve release ____ which acts on ____receptors to cause ____ of bronchiole smooth muscle.

A

vagus, acetylcholine, muscarinic, contraction

157
Q

Sympathetic nerve fibres that arise from the ____ release ____ which acts on ____ which cause ____ of bronchiol smooth muscle

A

spinal cord, norepinephrine, beta adrenoreceptors, dilation

158
Q

Draw out a flow diagram of the Hering-Breuer inflation reflex. What is the purpose of this reflex?

A

prevent over inflation of the lung
lung inflation - activation of lung strecth receptors (vagus afferents) - respiratory centres medulla oblongata (causes termination of inspiration) - bronchodilation - decreased airway resistance

159
Q

What effect does fibrosis have on lung compliance?

A

stiff lung caused by air contaminants so decreased complicance means increased pressure

160
Q

Which three airways structures contain cartilage

A

trachea, main stem bronchi and lobar bronchi

161
Q

How many generations are nonrespiratory?

A

16 - form the anatomical dead space

162
Q

What does dead space do to inhaled air?

A

causes contamination of freshly inhaled air diluting the oxygen content

163
Q

dead space is approximately ____ ml per kg

A

2.2 ml

164
Q

How. arethe respiratory structures held open?

A

lung parenchyma

165
Q

How many alveoli are there? What effect does this create?

A

> 300 million, funnel effect (cross sectional area increases from the trachea to the alveoli x 500)

166
Q

Describe the rate of air flow in the conducting zone compared to the respiratory zone

A

conducting zone - rapid and highly turbulent
slow and laminar in the respiratory zone due to large surface area.

167
Q

Airway resistance is dependent on what parameter?

A

airway diameter

168
Q

where is the highest and lowest resistnace respectively?

A

highest in the upper airways and lowest in the bronchioles

169
Q

What does the hering brauer reflex signal

A

it signals to the brain the state of the lungs

170
Q

Explain the reflex control of the airways in terms of the bronchioles

A

the bronchioles are innervated with sensory stretch receptors that generate action potentials during inflation that are sent to the brain stem. This triggers a reflex bronchodilation mediated via the sympathetic nervous system to reduce airway resistance and facilitates air flow into the alveoli

171
Q

explain in terms of the hering breuer reflex what happens during inhalation

A

inhale - stretch sensory endings on bronchioles - increases activity - mechanoreceptors ro medulla (vagal afferents) - sympathetic efferent to efferent target organ - bronchodilation as norepinephrine on beta adrenoreceptors

172
Q

Pulmonar circulation is best described as

A

a low pressure system carrying deoxygenated blood away from the heart and oxygenated blood to the heart

173
Q

How does branching contribute to resistance?

A

decreases resistance

174
Q

What is hypoxia?

A

low partial pressure of oxygen within the alveolus auch as through obstruction

175
Q

What is a consequence of hypoxia?

A

vasoconstriction

176
Q

Why is the response to hypoxia vasoconstriction?

A

arterioles supplying alveoli with deoxygenated blood constrict to redirect blood flow to a better ventilated alveoli, to optimise gas exchange and minimise V/Q mismatch

177
Q

What does the sheet flow model describe?

A

pulmonary capillaries are densely packed around the alveoli such that the individual capillary walls blend together leading to a sheet like micro-vascular structure with interstitial pillars

178
Q

What is the physiological advantage of sheet flow blood flow through pulmonary capillaries?

A

maximises the surface area of contact between blood and alveoli for gas exchange - leads to an optimal rate of diffusion

179
Q

Why does an increase in arterial pressure cause a decrease in pulmonary resistance?

A

An increase in pulmonary arterial pressure forces open previously collapsed vessels in a process known as vessel recruitment. This decreases pulmonary resistance, which normalizes the capillary hydrostatic pressure to prevent pulmonary oedema.

180
Q

What is meant by the V/Q ratio?

A

amount of air that reaches the lungs divided by the amount of blood flow in the capillaries in your lungs

(ventilation/perfusion)

181
Q

True/False, if th eventilation perfusion ratio is less than one, there is more ventilation than perfusion

A

false - ventilation (numerator) must be less than the perfusion (numerator) for the answer to be less than 1

182
Q

Why is there a difference in blood flow to the apex of the lung compared to the base?

A

gravity directs the blood further down

183
Q

When standing upright, the apex of the lung has a higher or lower degreee of perfusion at the base?

A

lower due to the impact of gravity

184
Q

when standing upright, the apex of the lung has a higher or lower ventilation than the base?

A

lower

185
Q

Alveoli volume is larger or smaller in the apex than in the base of the lung?

A

larger - pleural pressure is more negative at the top of the lung due to gravity, meaning that alveoli here at the apex are a larger size at FRC

186
Q

The apex of hte lung has a higher or lower V/Q than in the base of the lung?

A

Higher

187
Q

Due to gravity, both ventilation and perfusion are ____ at the apex of the lung. However, as blood has ____ mass than air, the ____ in perfusion from the apex of the lung to the base is ____ than the ____ in ventilation. This means that the V/Q ratio ____ from the apex to the base.

A

lowest, more, increase, greater, increase, decreases

188
Q

List 4 consequences of pulmonary hypertension

A
  • pulmonary oedema
  • breathlessness
  • increased hydrostatic pressure in pulmonary capillaries
  • fluid movement into alveoli
189
Q

How does partial pressure difference affect the diffusion of gas from the alveoli into the bloodstream?

A

The greater the pressure difference of each gas, the greater the driving force for movement.

190
Q

How does molecular weight of the gas affect the diffusion of gas from the alveoli into the bloodstream?

A

The lower the molecular weight of a gas, the faster the rate of diffusion

191
Q

How does of the diffusion barrier affect the diffusion of gas from the alveoli into the bloodstream?

A

The thinner the barrier the more rapidly diffusion can occur.

192
Q

How does surface area affect the diffusion of gas from the alveoli into the bloodstream?

A

a large surface area allows for rapid diffusion across the membranes. The combined surface area of alveoli in the human lung is between 50 - 100 m2.

193
Q

How does solubility of gas affect the diffusion of gas from the alveoli into the bloodstream?

A

the greater the solubility, the more the diffusion gradient is maintained.

194
Q

True Flase Increasing the time blood spends in a pulmonary capillary above the normal duration will increase the diffusion of oxygen into blood

A

false

195
Q

What is a diffusion limited gas

A

CO

196
Q

What is a perfusion limited gas

A

O2 and N2O

197
Q

Why is the pulmonary circuit a low pressure circuit?

A

lots of branching, increasing cross sectional area, decreased resistance

198
Q

The pulmonary vein carries oxygenated blood but is contaminated by blood from the ____

A

tracheobronchial circulation that bypasses the lungs (anatomical shunt)

199
Q

What factors control blood flow in the lungs?

A
  1. physical
  2. hypoxia
200
Q

what is lung parenchyma?

A

part of the lung involved in gas exchnage

201
Q

As pulmonary artery pressure increases, pulmonary vascular resistance decreases due to?

A

distension and recruitment of vessels

202
Q

Why does an increase in pressure result in a decreased resisatnce?

A

because recruitment of blood vessles increases the cross sectional area

203
Q

What two mechanisms maintain blood flow as pressure changes?

A

distension and recruitment

204
Q

What is distension?

A

widening of the capillaries to accommodate increased blood flow.

205
Q

Where is the blood flow greatest in the lung?

A

base bc gravity

206
Q

What is partial pressure of oxygen PaO2

A

a measurement of oxygen pressure in arterial blood. It reflects how well oxygen is able to move from the lungs to the blood.

207
Q

What factors cause regional variations in perfusion of the lung?

A
  1. hydrostatic pressure or pulmonary blood pressure (HP, Pa)
  2. arterial venous difference (Pv) (driving force for blood flow)
  3. alveolar pressure (PA)
208
Q

What is the arterial venous differnece

A

a measure of the amount of oxygen taken up from the blood by the tissues

209
Q

Describe the relationship of three pressures in each zone of the lungs

A

zone 1: top of the lung, lowest HP, bc poorly perfused –> PA>Pa>Pv

zone 2: Pa>PA>Pv

zone 3: Pa>Pv>PA (greatest HP because best perfusion)

210
Q

What is the reality of ventilation perfusion ration

A

0.8

because ventilation and perfusiona re both low at the top

211
Q

What is dyspnea, what causes it?

A
  • shortness of breath
  • pulmonary oedema - left heart failure, buold up. f blood in pulmonary vein, increased blood pressure in the lungs = oedema
212
Q

What is pulmonary hypertension?

A

when the pressure in the blood vessels leading from the heart to the lungs is too high.

213
Q

Co2 is x more times soluble than O2 and diffuses x faster than O2

A

25, 0.86x

214
Q

What is the driving force of CO2 from the blood to the alveolus

A

45-40 mmHg

215
Q

What is the driving force of O2 from the alveolus to blood?

A

100 - 40 mmHg

216
Q

Rate of gas uptake across the laveolar membrane is gas diffusion and perfusion limited, what doe these two terms mean?

A

diffusion - the amount of carbon monoxide taken up in the pulmonary circulation depends on the diffusion characteristics of the alveolar-capillary membrane, not the amount of pulmonary capillary blood flow. The uptake of carbon monoxide is said to be diffusion limited. (bonding ti,e to heamoglobin)

perfusion - In contrast to carbon monoxide, inspired nitrous oxide (N2O) does not combine with hemoglobin. Rather, it remains dissolved in plasma causing the partial pressure of nitrous oxide in the pulmonary capillary to increase, and the pressure gradient falls to zero. Consequently, additional uptake of nitrous oxide is dependent on it being carried away from the site of diffusion—in other words, it is dependent on pulmonary capillary blood flow. (limit to transport these gases is blood flow)

217
Q

What are the two methody for carrying oxygen in the blood

A
  1. binding with Hb - IL (150g Hb) carries 200 ml of O2
  2. dissolving in plasma - ONLY. -0.2ml/L at PO2 of 80 mmHg
218
Q

Normally, the partial pressure of O2 in the alveolus before it enters the blood is approximately?

A

100 mmHg

219
Q

Describe how the haem moiety influences oxygen binding. What is the process called?

A

first oxygen molecule takes longest to bind, but induces shape cahge - allosteric affect, making next binding site more available.
COOPERATIVE BINDING

220
Q

Describe the higher and lower points of the sigmoidal oxygen dissociation curve

A

higher - lungs: pressure and saturation is high becuase oxygen is loaded onto haemoglobin at the lungs. AFFINITY IS HIGHER for O2 at higher PO2 - encourgaes oxygen uptake

lower - tissues, less afinity of oxygen for haemoglobin because oxygen is leaving to the tissues. so lower PO2 means lower affinity and encourages release at tissue

221
Q

What does the oxygen dissociation curve show?

A

Saturation of O2 vs partial pressure of O2 and indicates the proportion og Hb bound with O2

222
Q

saturation is ____ of the amount of Hb present

A

independent

223
Q

Blood O2 levels depends on which two factors?

A

PO2 and Hb content

224
Q

What is the blood transport method for oxygen?

A

bound to haemoglobin, dissovled in solution

225
Q

O2 or CO2 has higher solubulity?

A

CO2

226
Q

What enzyme is needed for the reaction that converts CO2 to HCO3- to occur? Where is the highest concentration of this enzyme found?

A

carbonic anhydrase, red blood cells

227
Q

What causes the sigmoidal shape of oxygen-Hb dissociation curve

A

co-operative binding

228
Q

Why does the curve plateau at the top

A

haemoglobin is saturated with oxygen

229
Q

A patient comes in from a car accident with significant blood loss. The pulse oximeter records the patient’s blood O2 saturation at 98%. How will the O2 content within the blood be affected?

A

This patient will have significantly reduced O2 content within blood, due to the loss of haemoglobin and consequently the ability to absorb and transport O2. The remaining haemoglobin can still be fully saturated, hence will give a normal saturation reading despite the blood loss.

230
Q

Foetal haemoglobin has a left shifted O2 dissociation curve; for a given Po2 it has higher affinity for O2 than haemoglobin. Why is this useful for the developing fetus?

A

O2 saturation within maternal blood entering the placenta is low. Foetal haemoglobin’s high O2 affinity facilitates the binding of O2 at lower pO2, essentially helping ‘extract’ oxygen from the maternal circulation. This prevents hypoxia in the developing foetus.

231
Q

What is the function of myoglobin?

A

functions as an O2 store within muscle tissue

found in skeletal and cardiac muscle

232
Q

What causes a Bohr shift?

to the right

A
  1. decreased pH - for any given PO2, more O2 is released i.e HbO2 + H+ = HHb + O2 (HHb has a lower affinity to bind with O2 than Hb)
  2. increased temperature
  3. Increased pCO2 (increases H+ levels, also reacts with Hb to displace O2)
  4. increased DPG levels
233
Q

What causes a shift to the left?

A
  1. high pH
  2. low pCO2
  3. low temperature
234
Q

What does a Bohr shift imply regarding the availability of O2 to working tissues?

A

The availability of O2 to working tissues would be increased as it disassociates from Hb more easily.

235
Q

What is the haldane effect?

A

the increased carbon dioxide carrying capacity of haemoglobin in conditions of decreased pO2

236
Q

define the bohr effect in terms of CO2

A

a higher partial pressure of CO2 decreases haemoglobins affinity for oxygen

237
Q

What is the chloride shift?

A

the exchange of chloride for bicarbonate ions across the red blood cell membrane

238
Q

For a bohr shift the affinity for oxygen is reduced or increased?

A

reduced, promote giving up oxygen

239
Q

In terms of carbon dioxide transport in the blood, how much is transported in plasma

A

70%

240
Q

In terms of carbon dioxide transport in the blood, how much is transported in RBC

A

30%

241
Q

of the 30% CO2 transported in RBC, how much us rapidly formed bicarbonate i.e with carbonic anhydrase present

A

20%

242
Q

What detrmines the direction of reaction of CO2 once it has entered the RBC from the tissue?

A

law of mass action

243
Q

Gas exchange at the tissue

What detrmines the direction of reaction of CO2 once it has entered the RBC from the tissue?

A

law of mass action

244
Q

gas exchange at the tissue

What sets up the conditions for the chloride shift

A
  • CO2 enters the RBs from the tissue
  • When H2Co3 freely dissciates and HCo3- diffuses down its concentration gradient to the plasma, the RBC maintains its electrical charge by diffusing chlordie down its electrical gradient
  • maintains electroneutrality
245
Q

gas exchange at the alveolus

What direction is the chloride shift at the alveolus?

A

As Co2 enters the alveolus, HCO3- enters teh RBC thus CL- down its electrical gradient to the plasma

246
Q

Explain the CO2 dissociation curve in terms of the haldane effect

A

The Haldane effect describes the shift in the CO2 dissociation curve caused by oxygenation of Hb. Low Po2 shifts the CO2 dissociation curve to the left so that the blood is able to pick up more CO2 (e.g., in capillaries of rapidly metabolizing tissues).

247
Q

What do the two curves in the CO2 dissociation curve represent?

A

arterial (oxygenated) blood and venous (deoxygenated) blood

  • HbO2 has less affinity for CO2 than Hb. This means that HbO2 or arterial blood has curve displaced to the right - HALDANE SHIFT
248
Q

What are the two chemoreceptors in the body controlling breathing?

A

peripheral chemoreceptors
central chemoreceptors - in medulla oblongata

249
Q

Where are the peripheral chemoreceptors lacted?

A

aortic arch and carotid artery bifurcation. connected to the brain via gossopharyngeal nerves

250
Q

What are the stimulants for peripheral chemoreceptors?

A

highly sensitive to hypoxia, protons and carbon dioxide

251
Q

What is the reflex response of the peripheral chemoreceptors?

A

When activated increase both the rate and depth of breathing (minute volume increases) by acting on brainstem respiratory network. response is fast

252
Q

Where are the central chemoreceptors located?

A

neurons and astrocytes on the ventral surface of the medulla oblongata

253
Q

What are the stimulants for central chemoreceptors

A

sensitive to H+ ions liberated when CO2 diffuses across the blood brain barrier

254
Q

Why is response time slow in central chemoreceptors?

A

because it takes time to generate protons as levels of carbonic anhydrase is low in CSF

255
Q

What is the reflex response of the central chemoreceptors

A

increases minute ventilation in response to increasing CO2 (via dog leg relationship)

  • an increase in PaCO2 (hypercapnia) increases minute ventilation in a non linera manner
256
Q

How much percent of the response to hypercapnia is from peripherla and central chemoreceptors respectively?

A

central 80%
peripheral 20%

257
Q

What is congenital central hypoventilatory syndrome?

A

no central cehmoreceptors - hyperventilate in sleep

258
Q

what is nomral PaCO2 at rest?

A

40 mmHg

259
Q

In response to hypoxia, what pressure will cause an increase in ventlation?

A

100 mmHg PaO2

260
Q

Tidal volume is always:
a) greater than zero and less than Total Lung Capacity
b) greater than Residual Volume
c) greater than Functional Residual Capacity
d) greater than Residual Capacity and less than Total Lung Capacity
e) all options are correct

A

a.

261
Q

The lung:
a) exchanges CO2 between alveolar air and pulmonary capillary blood
b) exchanges H2O between alveolar air and ambient air
c) exchanges heat between alveolar air and ambient air
d) exchanges O2 between alveolar air and pulmonary capillary blood
e) all options are correct

A

e.

262
Q

Excitation of the Phrenic Nerve will:
a) increase the volume of the thorax by causing elevation of the diaphragm
b) reduce the volume of the thorax by causing elevation of the diaphragm
c) increase the volume of the thorax by causing relaxation of the diaphragm
d) increase the volume of the thorax by causing contraction of the diaphragm
e) reduce the volume of the thorax by causing contraction of the diaphragm

A

d.

263
Q

During Inspiration:
a) the glottis is open and alveolar air pressure is above atmospheric pressure
b) the glottis is open and alveolar air pressure equals atmospheric pressure
c) the glottis is open and alveolar air pressure is below atmospheric pressure
d) the glottis is closed and alveolar air pressure is above atmospheric pressure
e) the glottis is closed and alveolar air pressure is below atmospheric pressure

A

c.

264
Q

In pneumonia, bacterial infection causes the alveoli to become filled with liquid, thereby reducing the space for air. This condition would be expected to:
a) decrease the surface area for diffusive exchange of O2
b) decrease the surface area for diffusive exchange of CO2
c) increase the diffusion distance of O2 between air and blood
d) increase the diffusion distance of CO2 between air and blood
e) all options are correct

A

e.

265
Q

Ventilation is increased by:
a) a decrease in the partial pressure of CO2 in the cerebrospinal fluid
b) a decrease in the partial pressure of CO2 in the blood supply to the carotid bodies
c) a decrease in the partial pressure of CO2 in the inspired air
d) a decrease of pH of the cerebrospinal fluid
e) all options are correct

A

d. - CO2 to Carbonic acid, H+ increases, ventilation increase by central chemoreceptors

266
Q

Ventilation is increased by:
a) a decrease in the partial pressure of CO2 in the cerebrospinal fluid
b) a decrease in the partial pressure of CO2 in the blood supply to the carotid bodies
c) a decrease in the partial pressure of CO2 in the inspired air
d) a decrease of pH of the cerebrospinal fluid
e) all options are correct

A

d. - CO2 to Carbonic acid, H+ increases, ventilation increase by central chemoreceptors

267
Q

Hyperventilation will lead to:
a) increase of arteriolar PO2
b) decrease of alveolar PO2
c) increase of alveolar PCO2
d) increase of arteriolar PCO2
e) all options are correct

A

hyperventilation causes increased oxygen - a.

268
Q

The human pulmonary system:
a) senses PO2and PCO2 in the carotid and aortic bodies
b) is responsive to the pH of the cerebrospinal fluid
c) is more responsive to an excess of CO2 than it is to a lack of O2
d) contains stretch-receptors in lung tissue
e) all options are correct

A

e

269
Q

Which of the following is NOT considered a function of the respiratory system?
a) transport of oxygen and carbon dioxide to tissue cells
b) intake of oxygen and elimination of carbon dioxide
c) filtering inspired air
d) regulation of acid-base balance
e) production of sound

A

a.

270
Q

During normal resting pulmonary ventilation, all of the following are true, EXCEPT:
a) thoracic volume increases as the diaphragm contracts during inspiration.
b) the diaphragm forms a dome as it relaxes.
c) air comes in during inspiration because alveolar pressure falls below atmospheric pressure.
d) the phrenic nerve stimulates contraction of the diaphragm.
e) intrapleural pressure increases above atmospheric pressure during exhalation.

A

e.

271
Q

The reason the gradients for carbon dioxide can be smaller than those for oxygen and still meet the body’s needs is because:
a) much of the oxygen, but not the carbon dioxide, is consumed by red blood cells during transport.
b) carbon dioxide is a smaller molecule than oxygen.
c) oxygen forms ions once it enters the alveoli, and the electrical charges slow its movement across membranes.
d) carbon dioxide receives assistance crossing membranes from a carrier molecule.
e) carbon dioxide is more water-soluble than oxygen.

A

e

272
Q

Expired air has a greater oxygen content than alveolar air because:
a) more oxygen diffuses in across the mucosa of the bronchioles and bronchi.
b) newly inspired air is entering as expired as it is leaving.
c) oxygen is being generated by microbes in the upper respiratory tract.
d) some carbon dioxide is converted to oxygen in respiratory passages.
e) alveolar air mixes with air in the anatomic dead space on its way out.

A

e

273
Q

To say that hemoglobin is fully saturated means that:
a) it is carrying both oxygen and carbon dioxide simultaneously.
b) the red blood cells contain as many hemoglobin molecules as possible.
c) oxygen is attached to both the heme and the globin portions of the molecule.
d) some molecule other than oxygen is attached to the oxygen binding sites on hemoglobin.
e) there is an oxygen molecule attached to each of the four heme groups.

A

e

274
Q

Which of the following would be TRUE if the oxygen-hemoglobin dissociation curve is shifted to the right?
a) Partial pressure of carbon dioxide is increased.
b) Partial pressure of oxygen is decreased.
c) Levels of BPG are decreased.
d) Temperature is decreased.
e) pH is increased.

A

a. CO2 dissociates into carbonic acid, lower pH - Hb loses affinity for O2

275
Q

Airway resistance is affected primarily by the:
a) diameter of the bronchioles.
b) amount of surfactant.
c) partial pressure of each type of gas in inspired air.
d) thickness of the cartilage in the bronchial wall.
e) amount of elastic tissue in the lungs.

A

a. bronchioles have more smooth muscle, alter diameter, change resistance in airways

276
Q

Dalton’s Law states that:
a) the rate of diffusion is directly proportional to the surface area of the membrane.
b) at a constant temperature, the volume of a gas is directly proportional to the pressure.
c) in a mixture of gases each gas exerts its own partial pressure.
d) at a constant pressure, the volume of a gas is directly proportional to the temperature.
e) at a constant temperature, the volume of a gas varies inversely with the pressure.

A

c.

277
Q

Boyle’s Law states that:
a) in a mixture of gases each gas exerts its own partial pressure.
b) the rate of diffusion is directly proportional to the surface area of the membrane.
c) at a constant temperature, the volume of a gas is directly proportional to the pressure.
d) at a constant pressure, the volume of a gas is directly proportional to the temperature.
e) at a constant temperature, the volume of a gas varies inversely with the pressure.

A

e

278
Q

Compliance is affected primarily by the amount of elastic tissue in the lungs and the:
a) amount of surfactant.
b) diameter of the bronchioles.
c) thickness of the cartilage in the bronchial wall.
d) temperature of inspired air.
e) partial pressure of oxygen in inspired air.area of skin.

A

a

279
Q

During internal respiration, oxygen moves:
a) out of cells by primary active transport.
b) into cells by diffusion.
c) into cells by primary active transport.
d) into cells by secondary active transport.
e) out of cells by diffusion.

A

b

280
Q

Most oxygen is transported in blood by:
a) the heme portion of hemoglobin.
b) simply dissolving in plasma.
c) the globin portion of hemoglobin.
d) any type of plasma protein.
e) conversion to bicarbonate ion.

A

a

281
Q

If the partial pressure of carbon dioxide rises within homeostatic range, then:
a) chemoreceptors in the walls of the carotid sinus and aortic arch fire fewer action potentials.
b) more bicarbonate ions are produced from carbonic acid.
c) the pH of blood increases.
d) respiratory rate decreases.
e) more oxygen can attach to hemoglobin.

A

b

282
Q

Carbonic acid is produced when:
a) carbon dioxide combines with water.
b) carbon dioxide attached to hemoglobin.
c) oxygen and carbon dioxide combine.
d) oxygen combines with bicarbonate ion.
e) carbon dioxide combines with bicarbonate ion.

A

a

283
Q

Most carbon dioxide is transported in blood by:
a) any plasma protein.
b) the globin portion of hemoglobin.
c) the heme portion of hemoglobin.
d) simply dissolving in plasma.
e) conversion to bicarbonate ion.

A

e

284
Q

If the partial pressure of oxygen increases, then:
a) less oxygen can stay attached to hemoglobin.
b) respiratory rate increases.
c) more bicarbonate ions are produced from carbonic acid.
d) the pH of blood decreases.
e) more oxygen can attach to hemoglobin.

A

e

285
Q

In metabolically active tissues you would expect:
a) the partial pressure of carbon dioxide will be at its lowest point.
b) the partial pressure of oxygen will be higher than in the alveoli.
c) the percent saturation of hemoglobin will be less than it is near the lungs.
d) the pH will be slightly higher than it is in the fluid close to the lungs.
e) All of these are correct.

A

c

286
Q

The residual volume is the amount of air:
a) remaining in the lungs after the lungs collapse.
b) contained in air spaces above the alveoli.
c) that can be inhaled above tidal volume.
d) that can be exhaled above tidal volume.
e) remaining in the lungs after forced expiration.

A

e

287
Q

The tidal volume is the:
a) volume of air moved in and out of the lungs in a single quiet breath.
b) sum of the inspiratory and expiratory reserve volumes.
c) volume of air the lungs can hold when maximally inflated.
d) volume of air left in the lungs after a forced expiration.
e) percentage of alveolar air that is water vapor.

A

a

288
Q

ou would expect the partial pressure of oxygen to be highest in the:
a) intracellular fluid.
b) hepatic portal vein.
c) pulmonary veins.
d) pulmonary arteries.
e) interstitial fluid.

A

C

289
Q

If the partial pressure of carbon dioxide is decreasing, then:
a) there is an increase in the rate of the reaction converting carbonic acid into hydrogen ion and bicarbonate ion.
b) the partial pressure of oxygen must be increasing.
c) the pH will also be decreasing.
d) there is an increase in the rate of the reaction converting carbonic acid into water and carbon dioxide.
e) the affinity of hemoglobin for oxygen is decreasing.

A

d. if thereis a drop in CO2 we are going to have to react more H+ wiht HCO3- to produce more H2CO3 in roder to increase CO2 back to normal to resteablish equilibrium

290
Q

If a person is hypoventilating, then:
a) the pH of cerebrospinal fluid is increasing.
b) the partial pressure of carbon dioxide is decreasing.
c) the rate at which carbonic acid is dissociating into hydrogen ions and bicarbonate ions is increasing.
d) the rate at which carbonic acid is dissociating into hydrogen ions and bicarbonate ions is decreasing.
e) more oxygen will be able to bind to hemoglobin.

A

c

291
Q

A 27 year old man weighs 70 kg. At rest, his heart rate is 70 min-1 and his cardiac Stroke Volume is 70 mL. His Anatomic Dead Space is likely to be about:
a) 140 mL
b) 70 mL
c) 14 mL
d) 7 mL
e) 700 mL

A

deadspace approx 2.2 ml per kg so 2.2 x 70 is 140

292
Q

Breath-holding (hypoventilation) will cause the partial pressure of CO2 to
a) increase in venous blood
b) increase in alveolar air
c) increase in the tissues
d) increase in arterial blood
e) all options are correct

A

e

293
Q

A 27 year old man weighs 70 kg. At rest, his heart rate is 70 min-1 and his cardiac stroke volume is 70 mL. His respiratory frequency at rest is likely to be about:
a) 70 per min
b) 7 L per min
c) 0.7 per min
d) 7 per min
e) 70 L per min

A

D

294
Q

During an attack of asthma:
a) relaxation of bronchial smooth muscle decreases airway diameter, thereby decreasing airway resistance
b) contraction of bronchial smooth muscle increases airway diameter, thereby decreasing airway resistance
c) contraction of bronchial smooth muscle decreases airway diameter, thereby decreasing airway resistance
d) contraction of bronchial smooth muscle decreases airway diameter, thereby increasing airway resistance
e) relaxation of bronchial smooth muscle increases airway diameter, thereby increasing airway resistance

A

d

295
Q

A newborn baby that lacks pulmonary surfactant
a) must develop greater force in the inspiratory muscles in order to breathe
b) can be treated using an artificial surfactant delivered by an aerosol squirted into the trachea
c) was probably born prematurely
d) will, if untreated, experience Respiratory Distress Syndrome until the lungs undergo further maturation
e) all options are correct

A

e

296
Q

Surface tension exists in alveoli because:
a) polar water molecules are more strongly attracted to each other than to gas molecules in the air.
b) polar water molecules are more strongly attracted to gas molecules in the air than to each other
c) movement of gas molecules within alveoli creates electrical charges that attract each other.
d) surfactant is very sticky.
e) elastic fibers in the basement membrane form linkages that collapse alveoli.

A

a

297
Q

Based on your knowledge of the gas laws and molecular activity, which of the following would you expect to result from an increase in temperature?
a) The partial pressure of the gas will decrease.
b) More of a particular gas can be dissolved in a liquid.
c) A particular gas will diffuse across membranes at a faster rate
d) The volume of a particular gas will decrease.
e) The solubility coefficient of a particular gas will increase.

A

c

298
Q

Emphysema is characterised by
a) increase of lung compliance
b) trapping of air in enlarged alveoli
c) increased effort to expire
d) loss of lung tissue
e) all options are correct

A

e

299
Q

The rate of diffusion of O2 across the alveolar membrane is dependent on the difference in
a) partial pressure of oxygen between alveolar air and the pulmonary venous blood
b) content of oxygen between alveolar air and pulmonary arterial blood
c) content of oxygen between alveolar air and pulmonary venous blood
d) solubility of oxygen between pulmonary arterial and venous blood
e) partial pressure of oxygen between alveolar air and pulmonary arterial blood

A

e. rate of diffusion is depndent on partial pressure

300
Q

If air is introduced into the intrapleural space:
a) the volume of the lung on the same side increases, as does the volume of the thorax
b) the volume of the lung on the same side decreases, but the volume of the thorax increases
c) the volume of the lung on the opposite side increases, as does the volume of the thorax
d) None of these options are correct
e) the volume of the lung on the same side decreases, as does the volume of the thorax

A

b

301
Q

Emphysema is characterised by development of a ‘barrel chest’. This is due to:
a) gain of elastic tissues in the lung, thereby impairing expiration
b) gain of elastic tissues in the lung, thereby impairing inspiration
c) loss of elastic tissues in the lung, thereby impairing expiration
d) loss of elastic tissues in the lung, thereby impairing inspiration
e) loss of elastic tissues in the lung, thereby increasing anatomic dead-space

A

c. loss of elastic tissues, increased compliance - loss of elastic tissue measn less elastic recoil in expiration, harder to expire

302
Q

f, Heaven forbid, you suddenly lost all of your haemoglobin, then, provided that you were still inhaling room air at sea level, the CONTENT of oxygen per litre of blood would be about:
a) 3 mmHg
b) 98.7%
c) 3 ml
d) 203 ml
e) 200 ml

A

c. content is mesured in ml

303
Q

f, Heaven forbid, you suddenly lost all of your haemoglobin, then, provided that you were still inhaling room air at sea level, the CONTENT of oxygen per litre of blood would be about:
a) 3 mmHg
b) 98.7%
c) 3 ml
d) 203 ml
e) 200 ml

A

c. content is mesured in ml

304
Q

The Anatomic Dead Space:
a) is filled with alveolar air at the end of a normal inspiration
b) represents a survival advantage since it ensures that fresh air enters the alveoli with each breath
c) excludes the volume of the trachea
d) represents approximately 3% of a Tidal Volume at rest
e) all options are incorrect

A

e

305
Q

Which of the following statements about bronchi is INCORRECT?

Because of their small diameter, they don’t require cartilage to support their walls.
They form airways extending between the trachea and the bronchioles.
They are lined with an epithelium specialised to secrete and transport a mucous sheet upwards towards the pharynx.
They cannot participate in gas exchange because their walls are too thick to allow rapid diffusion.
Tertiary bronchi supply air to units of the lung called bronchopulmonary segments.

A

a

306
Q

Which of the following is NOT found in or on the walls of alveoli?

macrophages
endothelial cells of capillaries
squamous (Type 1) epithelial cells
surfactant-secreting (Type II) epithelial cells
mucus-secreting epithelial cells

A

mucus secreting epithelia cells - it would increase diffusion distance - not optimal

307
Q

The right lung:

receives deoxygenated blood from the left ventricle
has a pronounced notch, the cardiac notch, which accommodates the heart
is covered with a smooth, slippery parietal pleura
has three lobes and two fissures (horizontal and oblique)
is attached on its lateral surface to the right primary bronchus at a region called the hilus

A

has three lobes and two fissures

308
Q

The muscles of ventilation are:

smooth muscles innervated by cranial nerves
skeletal muscles innervated by spinal nerves
smooth muscles innervated by spinal nerves
cardiac muscles
skeletal muscles innervated by cranial nerves

A

b

309
Q

Which of the following lists the structures in the correct order of air flow?

nasopharynx, oropharynx, trachea, bronchioles, bronchi
nasopharynx, oropharynx, laryngopharynx, trachea, alveoli
oropharynx, laryngopharynx, nasopharynx, trachea, alveoli
oropharynx, laryngopharynx, trachea, bronchioles, bronchi
nasopharynx, laryngopharynx, oropharynx, trachea

A

2

310
Q

Which of the following is NOT a feature of the wall of the trachea?

ciliated epithelial cells
mucus-producing cells
C-shaped plates of cartilage
stratified squamous epithelium
elastic fibres

A

d

311
Q

Which of the following statements is CORRECT?

The walls of the alveoli contain mucus-producing cells
The pulmonary vessels carry oxygenated blood to the lung
The trachea branches directly into a right and left bronchiole, which then enter the lungs
The wall of the alveoli does not contain elastic fibres
Macrophages clear foreign particles from the alveolar space

A

5

312
Q

An airway of the lung is relatively thick-walled. It lacks supporting cartilage and there are no mucous glands. The diameter of the airway can be varied using smooth muscle in the wall. Most, but not all, of the cells lining the airway are ciliated. The airway is:

a bronchus
a bronchiole
the trachea
an alveolar sac
an alveolar duct

A

2

313
Q

hich of the following is found throughout the respiratory tree, ie. in both conducting and respiratory regions?

elastic fibers
Type II cells
ciliated epithelial cells
cartilage
mucus-secreting cells

A

1

Medsci 142 (10 decks)

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