Physiology 1 & 2 Flashcards

1
Q

Internal respiration?

A

Intracellular mechanisms that produce O2 and use CO2

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2
Q

External respiration?

A

Sequence of events that lead to the exchange of O2 and CO2 between the external environment and the cells of the body

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3
Q

4 steps of external respiration?

A

Ventilation (mechanical process of moving air into and out of the lungs)Gas exchange between the alveoli and bloodGas transport in blood (between lungs and tissue)Gas exchange at tissue level

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4
Q

Boyle’s law

A

At any constant temperature, the pressure exerted by a gas varies inversely with the volume of the gas

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5
Q

Why does air move into the lungs during inspiration?

A

During inspiration, the inspiratory muscles contract causing the thorax and lungs to expand. This causes the intra-alveolar pressure to become less than the atmospheric pressure due to Boyle’s law causing air to flow down the concentration gradient into the lungs

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6
Q

What holds the thoracic wall and lungs in close proximity? (2)

A

Intrapleural fluid cohesivenessNegative intrapleural pressure

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7
Q

What is the intracellular fluid cohesiveness?

A

Water molecules in intrapleural fluid are attracted to each other and resist being pulled apart causing the plural membranes to stick together

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8
Q

Negative intrapleural pressure?

A

The intracellular pressure is below atmospheric pressure which creates a transmural pressure gradient forcing the lungs outwards and chest inwards

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9
Q

Atmospheric pressure value?

A

760mmHg

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10
Q

Intralveolar pressure value?

A

760mmHg

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11
Q

Intrapleural pressure value?

A

756mmHg

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12
Q

Is inspiration an active or passive process?Expiration?

A

ActivePassive

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13
Q

Major inspiratory muscle?

A

Diaphragm

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14
Q

Inspiratory muscles?

A

Diaphragm and external intercostal muscles

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15
Q

what gives motor innervation to the diaphragm?

A

Phrenic nerves formed from C3, 4, 5 nerve roots

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16
Q

When does air stop entering the lungs?

A

When intra-alveolar pressure equals atmospheric pressure

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17
Q

How does expiration occur?

A

Relaxation of the inspiratory muscles causes the chest wall and lungs to recoil to their perspiratory size due to their elastic propertiesThis causes the intra-alveolar pressure to rise due to boyle’s law forcing air out of the lungs down the pressure gradient until intra-alveolar pressure = atmospheric pressure

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18
Q

Pneumothorax definiton

A

Air in the pleural space (causes the lung to collapse)

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19
Q

Types of pneumothorax?

A

Traumatic (hole in chest wall)Spontaneous (hole in lung wall)

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20
Q

What causes a lung to recoil during expiration?

A

Elastic connective tissueAlveolar surface tension

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21
Q

Alveolar surface tension?

A

Attraction between water molecules at liquid air interface

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22
Q

What reduces the alveolar surface tension?

A

Surfactant (lowers surface tension of smaller alveoli more than larger alveoli)

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23
Q

La Place’s law?

A

P=2T /r (the smaller alveoli have a higher tendency to collapse)

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24
Q

What is surfactant made of?

A

Lipids and proteins

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25
What is surfactant secreted by?
Type II alveolar cells
26
Respiratory distress syndrome of the newborn?
Developing metal lungs are unable to synthesise surfactant until later in the pregnancy meaning premature babies may not have enough surfactant
27
What helps to keep the alveoli open?
SurfactantAlveolar interdependancetransmural pressure gradient
28
What is alveolar interdependence?
If an alveolus starts to collapse the surrounding alveoli are stretched and then recoil exerting expanding forces in the collapsing alveolus
29
When does respiration become active (2)?
Due to exercise or disease
30
Accessory muscles of inspiration? (2)
SternocleidomastoidScalenus
31
What instrument is used to measure the air capacity of the lungs?
Spirometer
32
Tidal volume?Value for a normal healthy adult male
Normal volume of air displaced between normal exhalation and inhalation when extra effort is not applied 500ml
33
Residual volumeValue
Amount of air left in the lungs after a forced exhalation1200ml
34
Functional residual capacityValue
Volume air left in the lungs at the end of passive expiration 2200ml
35
Vital capacityValue
Maximum amount of air a person can expel from the lungs after a maximum inhalation4500ml
36
Total lung capacityValue
Most air you can inspire into your lungs5700ml
37
Inspiratory reserve volume Value
Additional air that can be forcefully inhaled after the inspiration of a normal tidal volume3000ml
38
Inspiratory capacityValue
volume of air that can be inspired after a normal expiration 3500ml
39
Expiratory reserve volumeValue
additional air that can be forcefully expired after the expiration of a normal tidal volume 1000ml
40
FEV1 full name and explanation?
Forced Expiratory volume in one second (dynamic volume)Volume of air that can be expired during the first second of expiration in an FVC
41
FVC stands forExplanation
Forced vital capacitymaximum volume that can be forcefully expelled from the lung following a maximum inspiration
42
FEV1 % (ratio) =
FEV1/FVC
43
What type of curve can be used to determine FVC and FEV1
Volume time curve
44
FEV1/FVC normal and asthmatic
Normal = >75%Asthmatic (obstructive) =
45
FVC and FEV1 for restrictive disease
FVC = lowFEV1 = lowRatio = normal
46
Airway flow =
F= change in pressure/ Resistance
47
Sympathetic/ parasympathetic stimulation causes bronchoconstriction/ bronchodilation
Para. = bronchoconstrcitonSym. = bronchodilation
48
Does airway resistance make it more difficult to inspire or expire
Expire
49
What happens to the intracellular pressure during inspiration and expiration?
Inspiration = fallsExpiration = rises
50
Why are the alveoli and airways compressed during active expirationWhat is this calledWho does this cause a problem for
Due to rising pleural pressureDynamic airway compressionPatients with airway obstruction
51
What helps push air out of compressed airways
Increased pressure upstream increases the driving pressure between the alveolus and airway therefore pushing air out of the alveoli
52
What happens during dynamic airway compression if there is an obstruction?
The driving pressure is lost over the obstructed segment causing a fall in the airway pressure along the airway downstream resulting in airway compression by the rising pleural pressure during active expiration (made worse if patient also has decreased elastic recoil of the lungs)
53
What is a peak flow meter useful for assessing patients with?
Obstructive conditions
54
Pulmonary compliance
measure of the effort that has to go into stretching or distending the lungs (volume change per unit of pressure change across the lungs)
55
What does less compliant lungs mean?
More work is required to produce a given degree of inflation
56
Some factors that decrease pulmonary compliance
pulmonary fibrosiSPulmonary oedemaLung collapsePneumoniaAbsence of surfactant
57
What type of pattern can decreased compliance show in spirometry
Restrictive pattern
58
When can compliance become abnormally increased
When the elastic recoil of the lungs is lost e.g. emphysema
59
What happens to compliance as you age
It increases
60
4 situations when work of breathing is increased
Pulmonary compliance is decreasedAirway resistance is increasedElastic recoil is decreasedneed for increased ventilation