W4 - Respiratory System Flashcards
1
Q
Importance of the respiratory system
A
Gas exchange
Acid-base balance reg
Vocalisation
Homeostatic reg of body pH
Protection from inhaled pathogens + irritating substances
2
Q
What are the types of respiration?
A
Pulmonary
Cellular
3
Q
What comes under pulmonary respiration?
A
Process of ventilation
O2 + CO2 exchange in lungs
4
Q
What comes under cellular respiration?
A
O2 utilisation
CO2 production
5
Q
Site of carina
A
Ridge at the base of the trachea
6
Q
What does the site of carina separate?
A
Openings or right + left bronchi
7
Q
What leads off from the trachea?
A
Right + left primary bronchus
8
Q
What leads off the right + left primary bronchus?
A
Secondary (lobar) bronchi
9
Q
What leads off the secondary (lobar) bronchi?
A
Segmental tertiary bronchi
10
Q
Where do the bronchioles branch off from?
A
Segmental tertiary bronchi
11
Q
What are the types of bronchioles?
A
Lobular
Respiratory
Terminal
12
Q
How many alveoli are there? What coverage??
A
480 million alveoli covering 75 square meters
13
Q
What are the different zones in respiration?
A
Conducting
Respiratory
14
Q
Purpose of the conducting zone
A
Moves air to respiratory zone
Humidifies, warms + filters air
15
Q
What components are found in the conducting zone
A
Trachea
Bronchial tree
Terminal bronchioles
16
Q
Purpose of the respiratory zones
A
Gas exchange
17
Q
What components are found in the respiratory zone
A
Respiratory bronchioles
Alveolar ducts
Alveolar sacs
18
Q
No. of tubes in trachea
A
1
19
Q
No. of tubes in bronchi
A
2, 4, 8
20
Q
No. of tubes in bronchioles
A
16
21
Q
Type II alveolar cell (septal cell)
Major functions
A
Synthesis + secretion of surfactant
Xenobiotic metabolism
Transepithelial movement of H20
Regeneration of alveolar epithelium after lung injury.
22
Q
What is Xenobiotic metabolism ?
A
Typically:
Lipophilic compounds –> more readily excreted hydrophilic metabolites.
23
Q
Definition for lipophilic
A
Tend to combine w. or dissolve in lipids or fats
24
Q
Describe Type I alveolar cells
A
Squamous
Very thin
25
Function of Type I alveolar cells
Involved in GE between alveoli + blood
26
What are alveolar macrophages?
Primary phagocytes of innate immune system
27
What do Alveolar macrophages do?
Clear air spaces of infectious, toxic or allergic particles that have evaded the mechanical defences of the respiratory tract, i.e nasal passages.
28
What comes under pulmonary ventilation / breathing?
Inhalation
Exhalation
(Exchange of air between atmosphere + alveoli)
29
What comes under external pulmonary respiration?
GE between alveoli + blood
30
What comes under internal cellular respiration
Systemic capillaries transport to tissue cells
Supplies cellular respiration
31
What law is inhalation based on?
Boyle's law
32
What does Boyle's law state?
Pressure of a gas in a closed container is inversely proportional to the vol of the container at a CONSTANT temp
33
What happens to the diaphragm, ribs and chest cavity during inhalation/inspiration?
D = Contracts, flattens + descends
R = Rise
CC = Elongates + enlarges
== ⬆️ air into lungs as intrapulmonic pressure is below atmospheric pressure
34
How does inspiration during physical activity differ from resting inspiration?
Diaphragm, rib cage + abdominal muscles synchronise to contribute.
Scaleni + external intercostal muscles between ribs contract = ribs rotate + move up + away from body.
35
What are the 2 factors from which expiration results from?
Natural recoil of stretched lung tissue
Relaxation of inspiratory muscles.
36
How are the thoracic dimensions reduced during strenuous activity?
Internal intercostal + abdominal muscles act powerfully on ribs + abdominal cavity
37
Intrapulmonary and intrapleural pressure relationships
Alveolar pressure changes during different phases of the cycle.
Equalizes at 760 mm Hg but doesn't stay there.
38
What is Intrapleural pressure
Air pressure in pleural cavity between visceral + parietal pleurae
39
Which is always less than the other?
Intrapulmonary or intra pleural pressures?
Intrapleural is always less than intrapulmonary
40
What is the intrapulmonary pressure during inspiration + expiration?
Inspiration = Subatmospheric
Expiration = Greater than atmospheric pressure
41
What are the effects to COPD?
Chronic inflammation of airways
Structural changes + collapse of small airways
Impaired exhalation
Lung hyperinflation
Altered diaphragm
Reduced motion
42
What 3 components are measured in the diaphragm release technique (DRT)
Diaphragm mobility
Respiratory pressures
Chest wall + abdominal kinematics
43
What does the diaphragm release technique (DRT) improve?
Diaphragm mobility
Inspiratory capacity
⬆️ Vital capacity
44
What has inspiratory muscle training (IMT) been observed to do for people with cervical spinal cord injuries?
⬆️ inspiratory muscle strength
Reduce dyspnea
⬆️ diaphragm thickness by 22%
45
What is dyspnea
Inordinate shortness of breath
Sense of breathing incapacity during PA
46
Tidal volume (TV)
Vol of air breathed in or out per breath
47
Inspiratory reserve volume (IRV)
Max inspiration after TV inspiration
48
Expiratory reserve volume (ERV)
Max expiration after TV expired
49
Total lung capacity (TLC)
Vol. in lungs after max inspiration
50
Residual lung vol (RLV)
Vol in lungs after max expiration
51
Forced Vital Capacity (FVC)
Max vol of air expired after Max inspiration
52
How is minute ventilation calculated?
TV x breathing freq
53
What % of the tidal volume reaches the respiratory zone?
70%
54
What % of the tidal volume reaches the conducting zone?
30%
55
What is airway resistance?
Amount of resistance to the flow of air through the respiratory tract during inspiration + expiration
56
What does the degree of airway resistance depend on in particular?
Diameter of airway
Whether flow is laminar or turbulent
57
Airway resistance represents 80% of the resistance to the flow of air, what causes the other 20% resistance?
Friction of pulmonary + thoracic tissues
58
What does P(little ATM) stand for?
Atmospheric pressure
59
What does P(little A) stand for?
Alveolar pressure
60
What does V stand for?
Volumetric airflow
61
Equation for measuring airway resistance
R(little AW) = P(little ATM) - P(little A) / V
62
Functional residual capacity (FRC)
Vol or air in lungs at end of passive expiration
63
What is the total lung capacity ?
~6L
64
How is vital capacity calculated?
TV + IRV + ERV
65
How is inspiratory capacity calculated?
TV + IRV
66
How is the functional residual capacity calculated? (FRC)
ERV + RV
67
How is total lung capacity calculated?
TV + ERV + IRV + RV
68
Where is the respiratory centre located?
Medulla oblongata + pons in the brainstem
69
What are the 3 major respiratory groups of the respiratory centre?
Dorsal respiratory group
Ventral respiratory group
Pontine respiratory group
70
Which of the 3 major respiratory groups of the respiratory centre are found in the medulla?
Dorsal respiratory group
Ventral respiratory group
71
Which of the 3 major respiratory groups of the respiratory centre are found in the pons?
Pontine respiratory group
72
What are the 2 centres of the pontine respiratory group?
Pneumotaxic centre
Apneustic centre
73
In order to regulate the RATE + DEPTH of breathing, where does the respiratory centre receive input from?
Chemoreceptors
Mechanoreceptors
Cerebral cortex
Hypothalamus
74
What is the main function of the medulla oblongata?
Sends signals to the muscles that initiate inspiration + expiration
75
Pneumotaxic centre/area of the pontine respiratory group.
Where?
Superior portion of pons
76
Pneumotaxic centre/area of the pontine respiratory group.
What does it do?
Works w/ the medulla rhythmicity area to set the rhythm of breathing.
Has inhibitory impulses.
Prevents lungs from becoming too full w. air.
Limits duration of inspiration.
77
Pneumotaxic centre/area of the pontine respiratory group.
Active or inactive?
Active
78
Pneumotaxic centre/area of the pontine respiratory group.
Quicker or slower than the apneustic centre/area?
Quicker
79
Apneustic centre/area of the pontine respiratory group.
Where?
Inferior portion of pons
80
Apneustic centre/area of the pontine respiratory group.
What does it do?
Coordinates transition between inspiration + expiration.
stimulate inspiratory area to prolong inspiration + slow rate of breathing
81
Apneustic centre/area of the pontine respiratory group.
When does it occur?
Only when pneumotaxic area is inactive.
82
Which is overridden by which?
Apneustic vs Pneumotaxic
Apneustic is overriden by pneumotaxic
83
Apneustic centre/area of the pontine respiratory group.
Active or inactive?
Active
84
Apneustic centre/area of the pontine respiratory group.
Quicker or slower than the Pneumotaxic centre/area?
Slower
85
Medullary rhythmicity area at REST
What happens during active inspiration?
w/in 2 secs:
Diaphragm + external intercostals actively contract
86
Medullary rhythmicity area at REST
What happens during active expiration?
W/in 3 secs:
Diaphragm + external intercostals relax
Elastic recoil or chest wall + lungs
87
Medullary rhythmicity area - FORCED BREATHING
What happens as soon as forced inspiratory happens?
Expiratory area is activated:
Internal intercostals + abdominal muscles contract
= forced expiration
88
What dictates how we breathe?
Voluntary Control
Involuntary Control
89
Where are central chemoreceptors located?
Medulla oblongata of brainstem
90
What do central chemoreceptors do?
Detect changes in arterial pCO2.
91
What happens once changes in arterial pCO2 are detected by the central chemoreceptors?
Send impulses to respiratory centres in brainstem to:
initiate changes in ventilation to restore normal pCO2.
= hyperventilation.
92
What happens to CO2 once it enters the Cerebrospinal fluid (CSF) after diffusing across the blood brain barrier from the arterial blood?
Carbonic anhydrase converts it to HCO3- + H+.
H+ = ⬇️ CSF pH
Both elevated pCO2 + red pH stimulate the chemoreceptors.
93
Where are the peripheral chemoreceptors primarily located?
Carotid body
...then the aortic body
94
Function of the peripheral carotid chemoreceptors
Stimulate breathing in response to hypoxia.
95
What is the carotid sinus nerve?
A branch of the glossopharyngeal nerve (a.k.a cranial nerve 9 (CN9))
96
What does the carotid sinus nerve do with the branch of the glossopharyngeal nerve?
Provides sensory innervation to the carotid body.
97
What is the sensory nerve fibre in the glossopharyngeal nerve sensitive to?
⬇️ in p02
98
What do the aortic body peripheral chemoreceptors do?
Measure changes in bp
99
Where do signals from the aortic body chemoreceptors travel down to the medulla?
Vagus nerve (CN X)
100
What are the respiratory stretch receptors activated by?
Over inflation of the lungs
101
What happens when the respiratory stretch receptors are activated?
Inhibitory discharge is sent to the inspiratory area...
Expiration begins + lungs deflate
102
Where can irritant receptors be found?
Between airway epithelial cells
103
What are irritant receptors stimulated by?
Noxious gases
Cold + inhaled dusts
104
What happens once the irritant receptors have been activated?
Send APs down vagus nerve to cause:
Bronchoconstriction + ⬆️ resp rate
105
Where are proprioreceptors located?
In NM spindles + Golgi tendon organs
106
What are the 3 basic types of proprioreceptors?
Muscle spindles
Golgi tendon organs
Joint receptors (low-threshold mechanoreceptors)
107
What are afferent impulses?
Neural impulses travelling from sensory organs/receptors to the CNS
108
What are efferent impulses?
Neural impulses travelling from CNS to the organs/glands.
109
In a study inhibiting muscle afferent fb, what did they use to partially block sensory responses?
Lumbar intrathecal fentanyl
110
What was measured in the study inhibiting muscle afferent fb
Minute ventilation (V little E)
Breathing frq. (f)
Tidal vol
111
What is the most commonly used pulmonary function test?
Spirometry test
112
Overview of procedure for spirometry test
Patient breathes in to full inspiration
Hold their breath long enough to seal their lips around mouthpiece.
Patient forcibly expires until nothing left to expel.
113
For how long can the forced expiration for the spirometer test last for those who suffer from severe COPD?
up to 15 secs
114
How many spirometer readings should be taken?
3
Best 2 should be w/in 100ml or 5% of each other
115
What does spirometry measure?
Records vol vs time.
116
What after a spirometry test is used to determine where there's any evidence of restrictive or obstructive lung disease?
Ratio of FEV1 to FVC
117
What needs to be corrected for when looking at the individuals measurements of FEV1 and FVC?
FEV1 = Forced expiratory volume in 1 second
Sex
Ethnicity
Height
Age
118
How is FEV1 + FVC expressed after a spirometry test?
As a % of predicted for matched, healthy ind w/ no lung disease.
119
What happens to FEV1 with obstructive spirometry?
Decreases
w/ less than 70% of the total amount in the 1st second.
