Respiratory system Flashcards
(154 cards)
1
Q
What is the main function of the respiratory system?
A
Provide oxygen and eliminate CO2
2
Q
What are secondary functions of the respiratory system?
A
-microbial protection
-regulation of blood pH
-phonation (sound production)
-olfaction (smell)
-blood reservoir
3
Q
What structures make up the RS?
A
-Upper airways (nasal, pharynx, larynx)
-Trachea
-Lungs
-Muscles of respiration
-Rib cage and pleura
-parts of CNS
4
Q
what is the order from trachea to bronchi?
A
Trachea–> primary bronchus–> bronchi
–>bronchioles—>alveoli
5
Q
What is the structure/function of the Trachea?
A
the trachea has a C shaped cartilage on the anterior and smooth muscle in the posterior
-this allows support from the cartilage and elasticity from muscle
-its function is to allow air passage to and from the lungs
6
Q
What is the structure and function of the Bronchi?
A
The bronchi have plates of cartilage and smooth muscle; they don’t have a C shape like the trachea in order to allow for greater expansion
7
Q
what is the structure of the bronchioles?
A
Smooth muscle only
8
Q
What is the conducting zone?
A
a region in the lungs where air moves from the external environment into the internal
-there is NO gas exchange here
9
Q
What is the respiratory zone?
A
An area where gas exchange happens
10
Q
what is the structure of alveoli?
A
tiny, thin walled, capillary rich sac that exchanged O2 and CO2
11
Q
What kinds of cells are present in alveloi?
A
Type 1: Don’t divide and are susceptible to toxins
Type 2 alveolar cells: produce SURFACTANT which is important prevents alveoli from collapsing
-can differentiate into type 1 cells
12
Q
What do the alveolar walls contain?
A
Dense network of capillaries and small interstitial space
13
Q
Where does diffusion of O2 and CO2 occur inside the capillaries?
A
respiratory membrane
-extremely thin and easily damaged
14
Q
What are the steps involved in respiration?
A
1) VENTILATION- exchange of air between atmosphere and alveoli
2) EXCHANGE of O2 and CO2 between alveolar air and blood in capillaries
3) TRANSPORT of O2/CO2 through pulmonary and systemic circulation
4) EXCHANGE of O2/CO2 between blood in tissue capillaries and cells in tissues
5) UTILIZATION of O2 and production of CO2 in cells
15
Q
What ways is airflow produced?
A
16
Q
What 3 kinds of respiratory muscles are there?
A
1) Pump muscles
INSPIRATORY- diaphragm, external intercostals, parasternal intercostals
EXPIRATORY- abdominals, internal intercostal
2) Airway muscles
INSPIRATORY-tongue protruders (genioglossus), alae nasi, pharynx, larynx
EXPIRATORY-pharynx, larynx,
3) Accessory muscles
INSPIRATORY- sternocleidomastoid, scalene, pectoralis
17
Q
What differs from expiratory vs inspiratory muscles?
A
https://youtu.be/6bkjJWBBnCo?si=nA7_PnvDg3om1x2t
18
Q
What is the difference in movement between the external intercostals and parasternal intercostals for inspiration?
A
External- contract and pull ribs UP in a bucket handle motion
-increases volume of thorax
Internal-contract and pull sternum forward in pump handle motion
19
Q
What abdominal muscles are involved in expiration? and what are characteristics of them?
A
External oblique
Internal oblique
Rectus abdominis
Transverse abdominis
These muscles are relaxed at rest and are involved in other physiological functions (coughing. vomiting, posture)
20
Q
What is the function of the internal intercostals for expiration?
A
They are relaxed at rest and push the rib cage down when contracted to push out as much air as possible
21
Q
What muscles are involved in inspiration?
A
22
Q
what muscles are involved in expiration?
A
23
Q
What is the function of the accessory inspiratory muscles?
A
They are relaxed at rest and contract vigorously during exercise or forced respiration
scalenes- elevate upper ribs
sternocleidomastoid- raises sternum
pectoralis- contribute to quiet breathing at rest (elevate ribs)
24
Q
What happens to the muscles during inspiration at rest vs when forced?
A
25
What happens to the muscles during expiration at rest vs when forced?
26
What muscles help open the upper airways?
-tongue protruders
-alae nasi
-pharyngeal and laryngeal dilators (inspiratory)
-pharyngeal and laryngeal constrictors (expiratory)
27
what is obstructive sleep apnea?
Expansion of chest wall but air doesn’t enter because upper airways are blocked; signals are still sent for contraction but exchange of air doesn’t occur
-can cause brain damage and CVS issues
28
What 2 cells make up the epithelial layer in the conducting airways? how do they differ?
1) goblet cells
- produce mucus that trap inhaled particles
- cilia makes contact with mucus to move
-too much mucus fluid will cause cilia to slip while too little mucus won't allow for cilia to adhere to move the mucus
2) ciliated cells
-produce periciliary fluid (sol layer) with low viscosity that is optimal for ciliary activity
29
What is the last defense to inhaled particles in the alveoli?
Macrophages
30
What device converts airflow rates into electronic signals?
Electronic spirometer
https://youtu.be/WIBhxAG3os0?si=w32k0pj6iO3K0rfg
31
What is tidal volume (TV)?
volume of air moved in or out of the respiratory tract during each cycle (breath)
32
what is inspiratory reserve volume (IRV)
the additional volume of air that can be forcibly inhaled after normal inspiration
-maximum possible inspiration
33
what is expiratory reserve volume (ERV)?
the additional volume of air that can be forcibly exhaled after normal expiration
-maximum voluntary expiration
34
what is residual volume (RV)?
volume of air remaining in the lungs after maximal expiration
-cannot be measured with a spirometry test
-RV = FRC - ERV
35
what is vital capacity (VC)?
maximum volume of air forcibly exhaled after maximal inspiration
VC = TV + IRV + ERV
36
what is inspiration capacity (IC) ?
the maximal volume of air that can be forcibly inhaled
IC = TV + IRV
37
what is functional residual capacity (FRC)?
volume of air remaining in lungs at the end of a normal expiration
FRC = RV + ERV
38
what is total lung capacity (TLC)?
volume of air remaining in lungs at the end of a maximal inspiration
TLC = FRC + TV + IRV = VC + RV
39
How is total ventilation calculated (minute ventilation)?
tidal volume x frequency (L/min)
40
What is alveolar ventilation? what does it depend on?
The amount of air moved into the alveoli (respiratory zone) per minute
-depends on the anatomical dead space
-alveolar ventilation < minute ventilation
41
what effect does breathing pattern have on alveolar ventilation?
breathing shallow + fast there will be no alveolar ventilation because the air doesn't make it to the respiratory zone
breathing deep + slow increases alveolar ventilation due to increase in air going into the respiratory zone
-increasing DEPTH is more effective than increasing RATE of breath in increasing alveolar ventilation
42
What is FEV1?
it is the forced expiratory volume in the first second
-healthy people can blow most of the air out of their lungs in the first second
43
What is FVC?
forced vital capacity is the total amount of air that is blown out in one breath after max inspiration as fast as possible
(TV + IRV +ERV)
44
What does FEV1 / FVC represent?
it is the proportion of air that is blown out in one second ~80%
45
What are the 3 main respiratory patterns?
Normal, obstructive and restrictive
46
what is an obstructive respiratory pattern?
shortness in breath due to difficulty in exhaling all the air from the lungs
-air lingers in lungs
-damage to lungs or narrowing of airways
-exhalation is slower than normal
-FEV1 is reduced
-FVC is ~normal / reduced
-FEV1/FVC is reduced (<0.7)
47
what is a restrictive respiratory pattern?
inability to fully fill lungs with air due to restriction in lungs from fully expanding
-caused by stiffness in chest wall, weak muscles, or nerve damage
-ALS, lung fibrosis
-reduced vital capacity
-FEV1 reduced
-FVC reduced
-FEV1 / FVC ~normal
48
What lung volumes and capacities are unable to be measured by a spirometry test?
residual volume
- resulting in the inability to measure functional residual capacity and total lung capacity
49
HOw does the helium dilution method work?
Within the lungs, the helium blends with the pre-existing air, serving as a mixing chamber.
By evaluating the shift in helium concentration, one can accurately determine the patient’s functional residual capacity (FRC).
From this data, it’s then possible to calculate both the residual volume and the total lung capacity (TLC).
https://youtu.be/4nQApZ8Q0XM?si=u8IO_FhxGS6du8bi
50
What 2 mechanical properties of ventilation?
static; when no air is flowing
-maintain lung and chest wall at a certain volume
-intrapleural pressure (Pip/ Ptp) and transpulmonary pressure
-surface tension
-static compliance
dynamic; when lungs change in volume and air is flowing in/out (permits airflow)
-alveolar pressure (Palv)
-dynamic lung compliance
-airway and tissue resistance
51
what is ventilation?
movement of air between the atmosphere and the alveoli (bulk-flow of gas from high to low pressure)
52
what does boyles law state?
Pressure and volume are inversely proportional for a fixed amount of gas at a fixed T
53
how does air move in regards to pressure?
54
What is the air movement at the end and beginning of inspiration/expiration?
there is no air flow due to lack of pressure difference
55
what pressures are of concern in regards to airflow?
pressure of the alveoli and the atmosphere
56
what occurs when the pressure of the alveoli < pressure of the atmosphere?
air moves towards the alveoli
57
what occurs when the pressure of the alveoli > pressure of the atmosphere?
air moves towards the atmosphere
58
What pressures are responsible for moving air in/out of the lungs?
1) intrapleural pressure (Pip)
2) alveolar pressure (Palv)
3) transpulmonary pressure (Ptp)
59
what 2 layers of tissue encase the pleural sac
Parietal pleura(Outer layer)
-attaches to thoracic wall; lines inside wall
Visceral pleura(inside layer)
-wraps around lungs to protect and isolate it
60
What is intrapleural fluid?
fluid that reduces friction of lungs against the thoracic wall during breathing
61
What interaction determines the lung volume?
the interaction between the lungs and the thoracic cage
62
what is elastic recoil?
a tendency for lungs to collapse following inflation
63
what is intrapleural pressure?
the pressure within the pleural cavity; always subatmospheric due to opposing direction of elastic recoil of lungs and thoracic cage
-relative vacuum
-if Pip = Palv the lungs would collapse
https://youtu.be/OvMxXIkw_BE?si=y1DJya3uxxk51diV
64
what is alveolar pressure?
the pressure inside the alveoli
Palv = atmospheric pressure when glottis is open and no air flows in/out of lungs
65
what is the relationship that governs the gas exchange between the lungs and the atmosphere?
Palv - Patm
66
what is transpulmonary pressure?
The force responsible for keeping the alveoli open; pressure gradient across the alveolar wall (Ptp = Palv - Pip)
Palv should always be > Pip (Ptp>0) to maintain the lungs expanded in thorax
67
True or false?
Palv is a dynamic component that determines air flow
True
68
explain the change in volume in pressure during one breath
https://youtu.be/s1QFW1aSh5Q?si=6ToUO3mavmYCnMqQ
69
What resistive forces play a role during respiration?
1) inertia
2) friction
-lung tissue past itself during expansion
-lung and chest wall tissues sliding past each other
-frictional resistance to flow of air through the airways represents 80% of total airway resistance
70
how is flow calculated
flow = change in pressure / resistance
71
what are the 3 types of airflow resistance patterns?
laminar-little energy in airflow resistance; small airways distal to terminal bronchioles
transitional-extra energy needed to produce vortices; higher resistance
-through most of the bronchial tree
turbulent-resistance of airflow the highest; occurs in large airways (trachea, larynx, pharynx)
72
what does resistance largely depend on?
radius of the airway
73
what does poiseuille's law state?
74
do larger or smaller airways experience higher resistance?
each small airway has a high individual resistance however since they are aligned parallelly they have a much lower aggregated resistance
R in series = R1 + R2 + R3...
R in parallel= 1/R1 + 1/R2 + 1/R3....
75
what is lung compliance?
a measure of the elastic properties of the lungs; how easily the lungs expand
76
what is static compliance?
lung compliance during periods of no gas flow
-determined by the P/V slope when measured at FRC
77
what is dynamic compliance?
pulmonary compliance during periods of gas flow
-reflects lung stiffness and airway resistance; compliance falls when either increase
78
what determines lung compliance?
Elastic components and airway tissues (localized in alveolar walls and around vessels / bronchi)
-elastin; like strong twine,high tensile strength inextensible
-collagen; like a weak spring, low tensile strength, extensible
Surface tension at the air-water interface within the alveoli
79
what is hysteresis?
defines the difference between the inflation and deflation compliance paths
-it exists because a greater pressure difference is required to open a previously closed airway rather then to keep an open airway from closing
80
what is emphysema?
the destruction of elastin and alveolar walls resulting in increased compliance of the lungs (floppy lungs)
-decreased elastic recoil; little change in PTP, large change in lung volume
81
what is pulmonary fibrosis?
collagen deposition in the alveolar walls resulting in lung stiffness or a reduction in lung compliance
82
what is alveolar surface tension?
a cohesive force where water molecules at the surface of a liquid-gas interface are attracted to the water molecules within the liquid mass
83
how does surface tension affect lung compliance?
surface tension decreases the volume of compressible gas inside the alveoli and increases its pressure
https://youtu.be/7ZMweT5o3Io?si=si6cQbr7CFka9OD9
84
what is the relationship between surface tension / radius on pressure in Laplace's equation?
pressure is proportional to surface tension while radius is inversely proportional
-decreasing the radius increases the pressure needed to keep open
-increasing surface tension increases pressure needed
84
what does surfactant do?
lowers the surface tension so we can breath with little effort
-produced by type II alveolar cells
-stabilizes alveoli from collapsing
85
what properties allow surfactant to decrease tension?
hydrophobic/philic properties decreases water density3
86
how does surfactant minimize the collapse of smaller alveoli into larger ones?
the thickness of surfactant decreases as SA increases so tension increases as the size of alveolar diameter increases
-this allows equalization of pressure between alveoli of different sizes
87
True or False:
Premature babies lack surfactant
True- premature infants lack surfactant and lung compliance decreases leading to increased work to breathe
88
how is pressure different throughout the lungs?
89
how is gas exchanged through capillaries?
DIFFUSION
90
what is air mostly composed of?
78% nitrogen
21% O2
1% H2O
<1% CO2
91
what is atm pressure at sea level?
760mmHg
92
what is the partial pressure of O2 and CO2?
160mmHg for O2
0.3mmHg for CO2
93
what does Ficks law state?
the rate of transfer of gas through a sheet of tissue / unit time is proportional to the tissue area and the difference in gas partial pressure
-it is inversely proportional to the thickness
94
what determines solubility of gases in liquids?
-amount of gas transferred between alveoli and blood
-gas solubility in fluids
95
What does henry's law state?
96
Does a gas always contribute to partial pressure?
no, only a gas dissolved in a solution will contribute to the partial pressure
97
how does partial pressure of CO2 and O2 change from inspired air to alveolar air?
CO2 goes from nearly 0 to 40mmHg
O2 drops ~1/3
98
is the pressure of air greater in the air or in the alveoli? why?
greater in the air due to humidity of air, loss of O2 in blood diffusion, mixing of inspired air with alveolar air
99
what determines PO2?
-PO2 in atmosphere
-Alveolar ventilation
-respiratory frequency
-Metabolic rate
-Perfusion
100
what determines PCO2?
-PCO2 atmosphere
-Alveolar ventilation
-Metabolic rate
-Perfusion
101
What effect on PO2 / PCO2 does increasing alveolar ventilation have?
increases alveolar PO2
decreases alveolar PCO2 (more similar to air ~0)
102
What effect on PO2 / PCO2 does increasing metabolic rate (O2 consumption / CO2 production) have?
decreases alveolar PO2
increases PCO2
103
what is a marker of healthy gas exchange between alveoli and blood?
blood gases reaching equilibrium quickly on their way through the lungs
104
what is perfusion of the lungs?
passage of fluid / blood through circulatory / lymphatic system to tissues
105
what is the pressure difference between systemic circulation and pulmonary circulation?
systemic- high pressure, high resistance
pulmonary- low pressure, low resistance (1/10th of systemic) , high compliance vessels
106
what is capillary blood volume during excercise?
200mL compared to 70mL at rest
107
when do capillaries collapse?
when capillary pressure < alveolar pressure
-capillaries close off and blood is directed to other capillaries with higher pressure
108
what is the relationship between ventilation and perfusion?
https://youtu.be/UKsOLb5XWa0?si=tljDHKE1B_15uuL3
109
What occurs with ventilated alveoli that lack perfusion?
dead space; air is not taken up by blood due to lack of circulation of new blood through the capillary system
110
What occurs with alveoli that have perfusion but no ventilation?
a shunt; a portion of the blood doesn't get oxygenated and goes back to arterial blood
111
where is ventilation greatest? why?
it is greatest near the base of the lungs due to gravity
-alveoli start more deflated so they are able to expand more
112
True or false:
ventilation-perfusion relationship is uniform throughout a healthy lung
False. blood flow and alveolar ventilation are reduced in the apical lung
113
What 2 forms is O2 carried in/
-dissolved (2%)
-With hemoglobin (98%)
O2 solubility is low so it gets bound to hemoglobin
(3mL O2/L blood vs 197mL O2/ L blood with hemoglobin)
114
How many O2 molecules can Hb bind to? what is each for called for bound O2 vs non bound O2?
Up to four O2 molecules
-deoxyhemoglobin (no O2)
-oxyhemoglobin (O2 bound)
115
Why is the O2 dissociation curve sigmoidal?
As each O2 molecule binds, the affinity of O2 to Hb increases
-also sensitive to pH PCO2 and Temp
https://youtu.be/r-16hB76Ark?si=pjZPWy2U6-DLEZno
116
what is Hb saturation?
the percentage of available Hb binding sites that have O2 attached
Hb saturation of arterial blood is 100mmHg PO2 is 97.5%
Hb saturation of mixed venous blood with 40mmHg PO2 is 75%
117
what determines Hb saturation?
-Arterial PO2 (main)
-Cooperative binding
118
What does the plateau of the curve signify? what pressure does it contain?
The plateau shows that the saturation stays high over a wide range of alveolar PO2; 60-100mmHg
-this provides a safety factor incase pressure decreases, it will still allow for saturation if Hb
119
What is the significance of the steep portion? what pressure does it contain?
the steep portion shows that large amounts of O2 are unloading within a small change in pressure; 40-60mmHg
-75% of O2 saturation of Hb at 40 mmHg
-PO2 must still remain high in capillaries to drive diffusion
120
What is the significance of the very steep portion? what pressure does it contain?
Changes in metabolic rate will increase / decrease PO2; 10-40mmHg
121
at rest what is the saturation level of Hb leaving tissues?
75%
122
How does the curve shift in response to changes in [Hb]?
123
how does CO affect the curve?
CO has 200x more affinity for Hb so it reduces the O2 -Hb binding
-shifts the curve to the left showing an increases in affinity of CO to Hb
124
how is O2 moved into the lungs and tissues?
pressure gradients dictate the movement of O2
-O2 dissolves briefly into plasma before binding to Hb or being released into tissues
https://youtu.be/WXOBJEXxNEo?si=fhJO9AciX_DCchWB
125
what factors affect the Hb-O2 dissociation curve ?
ph, Temp and Pco2
shift to right- REDUCTION in affinity of O2 to Hb = more unloading
shift to left-INCREASED affinity of O2 to Hb = less unloading
126
What three forms transport CO2 in the blood?
Carried in 3 forms:
1) dissolved (5%)
2) HCO3- (60-65%)
3) Carbamino compounds (25-30%)
CO2 has high solubility; 26.8mL /L of blood at 40mmHg
127
how is CO2 transported ?
https://youtu.be/VgpNSdWvrno?si=zWNHsJFvbZooqRnl
128
what is a carbamino compound?
CO2 combined with an amino group in blood proteins (globins in Hb)
129
How does CO2 help with unloading of O2?
deoxyHb has much high affinity for CO2 compared to OxyHb-CO2 helps to unload O2 from Hb at the tissues due to their competition for binding sites
130
what happens to the H+ released as a bi-product from HCO3- dissociation? Why is this needed?
majority gets bound to Hb; higher affinity for deoxyHb
-this helps to buffer the production of H+ in tissues / capillaries making the pH in the blood (7.4) slightly less acidic than in the venous blood (7.3)
131
What are the different types of respiratory and metabolic acidosis / alkalosis?
Respiratory acidosis- increased [H+] (increased Pco2 )
metabolic acidosis- increased [H+] independent from changes in Pco2
Respiratory alkalosis- decreased [H+] from decreased Pco2
metabolic alkalosis- decreased [H+] independent of Pco2 changes
132
where is the rhythm of breathing established?
In the CNS
-initiated in the medulla
133
what initiates breathing and what modifies it?
Initiated by: special neurons in the medulla
Modified by: higher structures of CNS
-central/peripheral chemoreceptors
-mechanoreceptors in lungs / chest walls
134
What are the 3 respiratory groups that help establish the automatic rhythm for contraction of respiratory muscles?
135
What neurons in the ventral respiratory group generate excitatory inspiratory rhythmic activity?
The prebotzinger complex (PreBotC)
136
What neurons generate active excitatory expiratory rhythmic activity?
The lateral parafacial (pFL)
137
what changes cause the neuronal networks to adjust the breathing rhythm?
The neuronal networks can generate their own activity; however, many factors affect the length and intensity
138
what is the effect of depressed preBotC neurons? what is a common cause?
Activity may be depressed by drugs (anesthetics and opioids/ fentanyl)
This leads to respiratory depression and eventually death for respiratory arrest
-naloxone can reverse opioid effects
139
How is ventilation controlled by [Po2], [Pco2] and [H+]?
-Chemical control
-Peripheral and central chemoreceptors
140
what are peripheral chemoreceptors?
receptors located in the carotid and aortic bodies that detect Po2 levels
https://youtu.be/1STBUJyyeYg?si=nPxcxp1tiy9-iKxB
141
what are carotid bodies?
very small chemosensitive structures that detect Po2 levels in the capillaries. They are highly vascularized and have a high metabolic rate
142
what are the chemosensitive cells in carotid bodies called? what is their structure and function?
Type 1 or glomus cells
-Neuron-like with voltage gated ion channels that trigger AP
-They release NT when stimulated to control the firing of sensory nerve endings
-sensitive to Po2, Pco2 and pH
143
what are type 2 cells in carotid bodies and what is their function?
They are sustentacular cells and they act as support in the Carotid bodies
144
what is the primary stimulus for peripheral chemoreceptors?
A decrease in arterial Po2
-low Po2 will increase firing rate for glomus cells
145
what level does stimulation of peripheral chemoreceptors occur at?
Arterial Po2 values below 60mmHg
-ventilation is stable between Po2 60-120mmHg
146
what is hypoxia?
low levels of O2
147
explain how the response to hypoxia is mediated by peripheral chemoreceptors
148
how are ventilation changes in arterial Pco2 different from ventilation changes in Po2?
PCO2 is more tightly controlled so smaller changes in Pco2 result in more dramatic changes in ventilation
149
What are central chemoreceptors?
specialized neurons located near the medulla
https://youtu.be/1STBUJyyeYg?si=nPxcxp1tiy9-iKxB
150
what is hypercapnia?
Too much CO2 in blood
151
explain how the response to hypercapnia is mediated by peripheral chemoreceptors
152
explain the respiratory response to metabolic acidosis?
153
explain the chemical control of ventilation when:
1) arterial Po2 decreases
2) arterial Po2 increases
3) production of non-CO2 acids increases
