3 Respiratory Flashcards

(58 cards)

1
Q

What is the tidal volume?

A

Tidal volume is the amount of air inhaled or exhaled during a normal breath, AT REST

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2
Q

What is the inspiratory reserve volume? (IRV)

A

The maximum amount of air a person can inhale after taking a normal breath.

It represents the extra capacity of the lungs for deep inhalation beyond the typical tidal volume,

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3
Q

What is the expiratory reserve volume?

A

The maximum amount of air a person can exhale after completing a normal exhalation.

It represents the additional air that can be forcefully expelled from the lungs

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4
Q

What is the inspiratory capacity?

A

The maximum amount of air a person can inhale after a normal exhalation.

It is the sum of tidal volume and inspiratory reserve volume
TV + IRV = IC

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5
Q

What is the vital capacity?

A

The maximum amount of air a person can exhale after taking a deep breath in.

It is the sum of tidal volume, inspiratory reserve volume, and expiratory reserve volume.

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6
Q

What is the functional residual capacity?

A

The amount of air remaining in the lungs after a normal exhalation.

It is the sum of expiratory reserve volume and residual volume
ERV + RV = FRC

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7
Q

What is the residual volume

A

The amount of air remaining in the lungs after a forceful exhalation.

It prevents lung collapse by maintaining air pressure within the lungs. This volume cannot be exhaled and is important for evaluating lung health and function in respiratory tests.

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8
Q

What is the total lung capacity?

A

The maximum amount of air the lungs can hold. It is the sum of all lung volumes: tidal volume, inspiratory reserve volume, expiratory reserve volume, and residual volume.
TLC provides a comprehensive measure of lung size

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9
Q

Why, under moderate sedation, do children have a higher risk of becoming hypoxic?

A

Slower breathing rate = pO2 may drop and pCO2 may increase
Ventilation may be less

Children have smaller residual volumes than adults and a faster metabolic rate
So they use up oxygen more quickly, leading to hypoxia

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10
Q

What is the main difference between men and women’s ventilation volumes?

A

Main different is inspiratory reserve volume (IRV) = meaning they have a naturally larger lung capacity

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11
Q

How does tidal volume change depending on the activity?

A

During exercise, tidal volume recruits other lung volumes = IRV & ERV

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12
Q

Name 2 other factors affecting ventilation

A

Airway resistance
Lung compliance

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13
Q

What causes an increase in airway resistance?

A

Decrease in airway diameter

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14
Q

What happens when airway resistance increases?

A

Decreased airflow to lungs

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15
Q

What is the relationship between airflow and airway resistance?

A

Inversely correlated

When airway resistance is high = low air flow
When airway resistance is low = high air flow

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16
Q

What are some things that cause an increase in airway resistance?

A

Airway constriction (asthma)
External compression
Obstruction = mucus

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17
Q

Describe what happens to airways when there is an allergic reaction

A

Release of histamine occurs
Causes smooth muscle contraction of airway walls
Constriction of bronchioles
Increases resistance, decreasing airflow to restrict breathing

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18
Q

What is released to decrease airway resistance?

A

EPINEPHRINE released by adrenal medulla
Causes smooth muscle of airways to relax

This dilates bronchioles = reducing resistance
Increase to airflow = promotes gas exchange

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19
Q

Define lung compliance

A

Lung compliance refers to the ability of the lungs to expand and stretch when air is inhaled.

High compliance means the lungs can expand easily, while low compliance means they are stiff and harder to expand.

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20
Q

What factors does lung compliance depend on?

A

Extent elastic fibres can stretch
Surface tension within the alveoli
Mobility of thoracic cage

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21
Q

What affect do surfactants have on surface tension within alveolus?

A

Prevent alveoli collapsing
Thus, promoting lung expansion + increasing lung compliance

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22
Q

What can affect the mobility of the thoracic cage?

A

Arthritis

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23
Q

What does change in lung volume affect?

A

Change in airway pressure

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24
Q

What is the equation for respiratory minute ventilation?

A

Volume of air moved per minute = breaths/min x tidal volume

25
What is the equation for alveolar ventilation?
Alveolar ventilation = breaths/min x (tidal volume - dead space)
26
What is the difference between respiratory minute ventilation and alveolar ventilation?
Same equation but alveolar ventilation takes into account DEAD SPACE
27
What can cause changes in tidal volume and dead space?
Disease If some part of alveoli cannot participate in gas exchange because of disease = they become dead space If there is poor lung compliance = tidal volume decreases (because airway resistance increases)
28
Define dead space and give examples
Dead space does not participate in gas exchange Bronchioles & trachae It includes anatomical dead space (airways) and physiological dead space (areas with poor or no blood flow). Increased dead space reduces the efficiency of breathing.
29
What compensates for changes in dead space and tidal volume?
Breathing rate (breaths/min) As per the equations of minute ventilation and alveolar ventilation Except for when under influence of sedatives, alcohol, etc
30
Why is ventilation-perfusion coupling important?
Only occurs in lungs, pulmonary capillaries If ventilation is high, but perfusion is low, or vice versa, gas exchange becomes inefficient. This process optimizes oxygen delivery and carbon dioxide removal.
31
What two factors are regulated to control ventilation-perfusion coupling?
Airway diameter (bronchioles) Pulmonary arterioles
32
What mechanism regulates bronchiole diameters in ventilation-perfusion coupling?
In regions with high airflow compared to local blood supply = decreased pCO2 Bronchioles constrict = reducing airflow so it's proportional to blood flow In regions with restricted airflow: increased pCO2 = bronchioles dilate Increase in airflow enhances CO2 elimination from ALVEOLI, preventing build-up
33
What mechanism regulates pulmonary arterioles in ventilation-perfusion coupling?
In regions with high airflow compared to blood supply: increased pO2, causing local arterioles to dilate More blood is made available for O2 to be picked up In regions with restricted airflow: low pO2, causes pulmonary arterioles to constrict Blood is re-channeled to alveoli w higher airflow and pO2, allowing more available O2 to be picked up
34
What part of brain controls ventilation?
Respiratory centres located within brainstems
35
Name the inspiratory neurones
Dorsal respiratory group
36
What is the average breathing rate?
12-20 breaths per minute
37
What is the role of the ventral respiratory group?
Function only during forced breathing During normal, quiet breathing (eupnoea), expiration is typically a passive process that occurs as the inspiratory muscles relax, allowing the lungs to recoil. However, during active or forced expiration (such as when exercising or coughing), the VRG is involved in generating the necessary muscle contractions for active exhalation
38
How does ventral respiratory group control breathing?
Innervates lower motor neurones controlling accessory respiratory muscles Increase in dorsal respiratory group (DRG) activity stimulates VRG neurones
39
What signals does the DRG integrate?
DRG integrates signals from VRG and pons
40
What is the role of pons in breathing?
Pons sends signals to DRG and VRG to modify respiratory rate and allow smooth transition between inspiration and expiration
41
What do central chemoreceptors sense, and what is the outcome?
They monitor pH that is dependent on CO2 levels in the brain Send signals directly to respiratory centers to regulate ventialtion
42
Where are central chemoreceptors located?
Medulla
43
What do peripheral chemoreceptors sense, and what is the outcome?
Monitor pO2 mainly but also pH and pCO2 in the ARTERIAL BLOOD Signal to respiratory centre via glossopharyngeal and vagus nerves
44
Where are peripheral chemoreceptors located?
Carotid bodies and aortic bodies
45
How is CO2 indicative of pH levels?
CO2 readily diffuses from blood into brain to combine with water = carbonic acid Acid dissociates into H+ and HCO3- ions H+ stimulates central chemoreceptors = sending nerve impulses to respiratory centres
46
How come the H+ is specific to pCO2 and not also affected by metabolic regions?
H+ cannot cross the BBB
47
Explain respiratory and metabolic ACIDOSIS
Resp system fails to remove CO2 (H+) normally generated by tissues (e.g decreased ventilation) Tissues generate excess acid or kidneys fail to get rid of acid
48
Explain respiratory and metabolic ALKALOSIS
Resp system removes too much CO2(H+) Maybe because of inappropriately increased ventilation Body has lost acid or gained excess alkali from other systems
49
What causes depression of respiratory control centres?
Sedatives Narcotic (opiod) drugs Alcohol Anaesthetics
50
How does voluntary control affect ventilation?
Act through cerebral cortex Consciously control respiratory muscles to regulate breathing patterns Can be overridden by chemoreceptor input to respiratory centres
51
What is CO2 narcosis?
When carbon dioxide (CO2) levels in the blood become excessively high, leading to respiratory acidosis. Depresses CNS and ventilation even further
52
How do pain and emotions affect ventilation?
Act through hypothalamus Stimulates or inhibits respiratory centres ANS may also play a role = sympathetic stimulation can cause bronchodilation and increases respiratory rate through anticipation or fear
53
How do pulmonary irritants affect ventilation?
May stimulate receptors in the airways = initiate protective reflexes to remve irritants Example = coughing and sneezing that involves apnea Forced closing of glottis with full lungs and sudden contraction of internal intercostal and abdominal muscles
54
How does lung hyperinflation affect ventilation?
During deep inhalation, stretch receptors send inhibitory signals to inspiratory neurones at DRG While stimulating expiratory centre of VRG to stop inspiration, begin expiration, and prevent over-stretching of lungs
55
Where are stretch receptors found to stop lung hyperinflation?
Visceral pleura Smooth mucles around bronchioles Large airways
56
How does deflation reflex affect ventilation?
During forced exhalation, receptors in alveolar wall of alveolar capillary network, sense decreasing lung volume Respond by inhibiting expiratory centres and stimulating inspiratory centres = stop expiration and begin inspiration
57
Is ventilation during exercise, dependent on pO2 and pCO2?
No it is often independent Other factors lead to increase in ventilation during exericse
58
Name 5 factors that lead to increase in ventilation during exercise
Anticipatory learned response Signals from motor cortex Proprioceptors in muscle and joints Hormones such as epinephrine and norepinephrine Lactic acid