Pulmonary Physiology Week 2 Flashcards
1
Q
Pulmonary arteries enter each lung at the _____ and travel adjacent to and branch with each airway generation to _________
A
hilum, respiratory bronchiole
2
Q
Pulmonary veins carry _____ blood from lungs to ______
A
oxygenated, left atrium
3
Q
Left pulmonary veins pass _______ whereas right pulmonary veins pass ______
A
in front of descending thoracic aorta; behind rt atrium and SVC
4
Q
Pulmonary capillaries are direct apposed to the _____ and about 0.6 microns thick
A
alveoli
5
Q
What is the normal pulmonary artery pressure [at the level of main pulm artery]?
A
15 mmHg
6
Q
Low pre-capillary arterial resistance leads to pulsatile motion in the microvascular bed. This motion is lost in severe __________
A
pulmonary arterial HTN
7
Q
Pulmonary vascular resistance is about ____ of systemic vascular resistance. There are no arterioles to regulate blood flow in this system.
A
1/10
8
Q
As pressure in the left atrium increases, what will happen to pulmonary vascular resistance as a function of increasing pulmonary artery pressure?
A
will no longer decrease because vascular bed is nearly fully distended
9
Q
If alveolar pressure is greater than capillary pressure, what happens to capillaries?
A
they collapse
10
Q
At what three levels does gas exchange occur?
A
within the tissues, within the blood and the alveoli (lungs themselves), [from environment into lungs]
11
Q
Each airway in the respiratory system divides into two daughter airways at each branching points. How many generations branch in the lungs from trachea to alveoli/alveolar sacs?
A
23
12
Q
The first 16 branching generations are the _______. Why is this area referred to as anatomical dead space?
A
conducting zone; air is passing through but there is no gas exchange
13
Q
Branches 17-23 are the _______ where alveoli are and gas exchange occurs between blood and lungs
A
transitional and respiratory zone
14
Q
True/False: As move down pulmonary tree, diameter of airways gets bigger and length gets shorter.
A
FALSE, get smaller [but do get shorter]
15
Q
As move down pulmonary tree, total cross sectional area gets ______
A
larger [ more branching you have - more cross sectional area you have ]
16
Q
The bronchi, trachea, bronchioles and terminal bronchioles make up the ________
A
conducting zone
17
Q
The respiratory bronchioles, alveolar ducts, alveolar sacs make up a functional unit called a _____ and are part of the _____ (final 7 generations)
A
acinus, respiratory zone
18
Q
Gas exchange occurs at the _____
A
alveoli
19
Q
The _______ is the entire amount that you can bring into your lungs [volume following MAXIMAL inspiration]
A
total lung capacity
20
Q
After maximal expiration, the amount left over is the ______
A
residual volume
21
Q
If you expel as much as you can from your lungs that volume is called the ________
A
vital capacity
22
Q
Vital capacity is not utilized very often. The volume inspired under normal resting conditions is called the ______
A
tidal volume
23
Q
The difference between volume in the lungs at end of tidal volume and 0 is the _______ [ volume remaining at end of normal tidal expiration]
A
functional residual capacity
24
Q
_________ is the difference between volume in lungs in normal inspiration vs the maximal amount to inspire [volume inspired during maximal inspiratory effort starting at end of normal tidal inspiration]
A
inspiratory reserve volume
25
________ is the difference between volume in lungs at normal tidal expiration and maximal amount expired to get to residual volume [volume expelled during maximal forced expiration starting at the end of normal tidal expiration]
expiratory reserve volume
26
The ______ is the volume inspired during maximal inspiration starting after at the end of normal tidal expiration
inspiratory capacity (IC)
27
The inspiratory capacity and functional residual capacity are each about 1/2 of _________. These volumes change based on certain factors however.
total lung capacity.
28
What happens to the functional residual capacity and inspiratory capacity when you lie down? Why?
inspiratory capacity becomes smaller, whereas functional residual capacity becomes larger. This is because the contents of your abdominal cavity push up against the diaphragm and make it harder to inspire.
29
Spirometer is handy for measuring lung volumes except for which 3?
residual volume, functional residual capacity, and total lung capacity because you cannot expire all the way down to 0
30
What are the three alternate ways that functional residual capacity can be measured?
nitrogen washout, helium dilution, plethysmography
31
Describe the nitrogen washout and helium dilution techniques.
Basically, our air is about 80% nitrogen. So can measure nitrogen content in spirometer while blowing pure O2 into person and eventually when nitrogen "washes out" will be able to figure out functional residual capacity. Helium dilution similar concept but with rare gas helium instead.
32
Describe pulmonary plethymography
Patient is placed in booth with single mouthpiece. Patient asked to inspire after last normal breath. Boyle's law is used to find the functional residual volume (PiVi = PfVf)
33
In a person that needs mechanical assistance to breathe, this can achieved by creating a pressure gradient how?
positive pressure at mouth which forces air into lungs
34
In a normal person that can breathe independent, how is a pressure gradient generated to move air into the lungs?
Create negative pressure around the lungs which allows the lungs to expand and allows air to move into the lungs.
35
Basically a person on mechanical ventilation breathes via ______ whereas a normal person breathes via ____
positive pressure breathing, negative pressure breathing
36
Negative pressure around the lungs is normally _____ in magnitude than inside the lungs due to having to work against _________
larger, elastic recoil pressure
37
The most important muscle for inspiration is the _______
diaphragm
38
Describe what happens to the chest cavity when the diaphragm contracts
The volume of the chest cavity increases [diaphragm moves downward] while the abdominal contents are forced down and forward
39
During inspiration, contraction of the _______ muscles also contributes by pulling the ribs upward, which expands the chest cavity
external intercostals [bucket handle]
40
What are the accessory muscles involved in inspiration? When are these used?
scalene and sternomastoid; used in exercise or COPD
41
The ____ muscles lift the first two ribs while the ______ raise the sternum
scalene, sternomastoid
42
Why is expiration normally a passive process?
The lung and chest wall are elastic and tend to return to their equilibrium positions upon relaxation of inspiratory muscles
43
When does expiration become active?
exercise
44
What are the most important muscles for active expiration?
abdominal and internal intercostals [pull rib cage down]
45
Name the three types of abdominal muscles involved in expiration
rectus abdominus, internal and external obliques, transversus abdominus
46
At functional residual capacity (FRC), ________ or the pressure inside the lungs is equal to atmospheric or barometric pressure (Pb)
alveolar pressure
47
The _________ or the pressure in the space between the lungs and chest wall is negative relative to the atmospheric pressure
intrapleural
48
There is a ___________ gradient that results which is the difference between the alveolar pressure and intrapleural pressure
transpulmonary pressure
49
The transpulmonary pressure reflects the elastic recoil properties of the lung and is sometimes referred to as the _______
elastic recoil P
50
Changes in ______ are due to changes in transpulmonary pressure
lung volume
51
During inspiration, which muscles contract which causes expansion of the chest cavity?
diaphragm and external intercostals
52
What happens to transpulmonary pressure as lung volume increases?
it increases too (wants to recoil like a balloon)
53
Changes in transpulmonary pressure are associated with changes in what two values?
transrespiratory pressure, transthoracic pressure
54
Explain the changes in interpleural P, lung volume, chest cavity volume, lung pressure, alveolar space pressure that occurs when breathing in and out
For inspiration, chest cavity expands, interpleural P becomes more negative, which leads to increase in lung volume, which decrease lung P, which creates a negative P in the alveolar space, which drives flow of air into lungs. Eventually gradient equilibrates. Then, decrease in interpleural P leads to decrease in lung volume which leads to dec in alveolar P which moves air out of the lungs
55
Expiration is driven by the _______ properties of the lung
elastic
56
________ is the change in volume for given change in pressure and is the INVERSE of _____
compliance, elastance
57
Elastance is equal to _____ whereas compliance is equal to ___
P/V, V/P
58
True/False: The lung is much more compliant at high lung volumes
FALSE, much less compliant
59
Compliance varies in different disease states. Compliance decreases with _______ while it increases with ______
pulmonary fibrosis; emphysema
60
Why is the pressure in the intrapleural space less than atmospheric?
elastic recoil properties of the lung
61
The elastic properties of the lungs are due to the ____ and ____ fibers that surrounds the bronchi and alveoli
elastin, collagen
62
The relationship between lung volume and intrapleural P differ between inspiration and expiration. This is called _____
hysteresis
63
T/F: The lung volume at any given intrapleural P is greater during inflation (inspiration) than deflation (expiration)
FALSE - greater during expiration
64
True/False: When there is no transpulmonary gradient, there is still some air in the lung (volume is not zero)
True
65
Why does filling a lung with saline increase compliance and eliminate hysteresis?
Reduces surface tension so lung is more compliant. The difference in compliance (volume/pressure) is due to the additional energy required during inspiration to recruit and inflate additional alveoli. During expiration, alveoli are smaller so surface tension is reduced.
66
Surface tension reflects the attractive forces that exist between adjacent molecules of liquid. in lungs, surface tension is due to the _________
liquid film lining the alveoli
67
The surface tension creates a force in the lung that contributes to the ______ and therefore decreases ______
elastic recoil pressure, lung compliance
68
Pressure generated by surface tension is directly proportional to ______ and inversely proportional to _____
surface tension, radius of sphere
69
If pressure is inversely proportional to radius, then why don't small alveoli collapse and large alveoli burst?
Because of surfactant! WOOT!
70
Surfactant is secreted by _______ and the main component is the amphipathic phospholipid dipalmitoyl phosphatidylcholine
type II alveolar cells
71
True/False: Hysteresis is due to surfactant
FALSE - due to surface tension; surfactant acts to DEC surface tension
72
True/False: Surfactant decreases hysteresis and increases complaince
TRUE DAT
73
Infant respiratory distress syndrome is common in infants born more than ___ weeks prematurely, and affects all infants born more than ___ weeks prematurely. It is caused by lack of _____.
6, 12, surfactant
74
______ is when hypoxia leads to a decrease in surfactant
acute respiratory distress syndrome
75
What are the effects of loss of surfactant on the compliance of the lungs and alveoli
decreased compliance so increases effort required to inflate the lungs and increases tendency for alveoli to collapse
76
The elastic recoil properties of the lung that tend to _____ lung volume are offset by the elastic recoil properties of the chest wall that tend to _____ the chest cavity. These opposing forces at what contributes to the _____ intrapleural pressure at rest
recoil, expand, negative
77
What happens in the case of a pneumothorax to the atmospheric and intrapleural pressures
They equalize so lung volume gets smaller and chest cavity gets larger [boyle's law no longer applies]
78
_______ is determined by the balance between the _____ elastic recoil properties of the chest wall and the ____ elastic recoil properties of the lung
functional residual capacity, outward, inward
79
True/False: At the functional residual capacity, elastic recoil of chest wall and of lung are equal and opposite and therefore neither wants to collapse or expand [equilibrium]
True
80
Describe what happens to functional residual capacity in a patient with emphysema
In emphysema, elasticity of lung decreases which increases compliance of the lung [steeper curve]. Because of this, they have extreme difficulty exhaling air. The high compliance of the lung results in many collapsed alveoli which makes inhalation difficult. Overall, the lung compliance is increased and the tendency for the lungs to collapse is decreased. The tendency of the lungs to collapse is less than the tendency of the chest wall to expand. The lung-chest wall system will seek a new, higher FRC which to balance the two forces which results in a barrel-shaped chest.
81
Describe what happens to the functional residual capacity in a patient with fibrosis
Lung compliance decreases will fibrosis and the tendency for the lungs to collapse is increased. Therefore, tendency of lungs to collapse is great than tendency of the chest wall to expand. The lung-chest wall system will seek a new, lower FRC so that opposing forces will be balanced again.
82
The effect of gravity contributes to a gradient of intrapleural P. At the base of the lung, what is the difference in intrapleural pressure compared to the apex of the lung? What effect does this have on the alveoli?
At base of lung, the effect of the weight of the lung is greatest, the intrapleural pressure is less negative than it is at the apex of the lung. Therefore, the alveoli at base are more compressed [ have lower volume ].
83
At base of lungs, are the alveoli less or more compliant?
Alveoli in base of lung are operating at a low volume, so lung is very compliant according to pressure/volume relationship. As such, small changes in transmural pressure tend to cause a greater change in volume.
84
At the apex of the lungs, are the alveoli less or more compliant?
Alveoli in the apex are operating at a higher volume, and therefore has lower compliance. As such, small changes in transmural pressure tend to cause less of a chance in volume.
85
Where in the lung are the alveoli best ventilated?
Base, because more able to change volume.
86
Other than elastic resistance, what are the two forms of non-elastic resistance encountered in lungs?
airflow and viscous
87
Air flows through tubes when there is a pressure gradient and what two types of flow?
a) laminar airflow (at low flow rates); b) turbulent airflow (at high flow rates)
88
What is the most important ways you can affect airflow?
changing the radius (via pousielle's law)
89
True/False: The rate of turbulent air flow is directly proportional to the radius
FALSE - true for laminar. turbulent relies more on pressure gradient.
90
True/False: A lower Reynolds number is more likely to indicate turbulent flow
HIGHER - FALSE
91
In terms of air flow, ______ will be found in the trachea whereas _____ will be further down in the bronchial tree
turbulent [especially during exercise], laminar [such as terminal bronchioles]
92
Turbulent flow is more likely when what three factors are present?
high velocity, large radius, dense gas
93
True/False: Turbulent flow creates less airway resistance than laminar flow
FALSE MORE
94
True/False: The resistance peaks at the terminal bronchioles
FALSE - the resistance peaks at the medium sized bronchioles and then decreases because total cross sectional area increases with branching
95
Airway radius is the principal factor affecting airway resistance. What affects airway radius?
lung volume
96
True/False: At low lung volumes, small airways can completely closed especially at the base of the lung
True
97
Why do patients with increased airway resistance tend to breathe at high lung volumes?
Going to reduce the resistance by expanding airway bc of increased volume
98
Bronchial _______ regulates airway radius and thus resistance
smooth muscle contraction
99
What is the action of sympathetic stimulation on airways?
Circulating epinephrine activates beta-2 adrenergic receptors which relax smooth muscle and decrease resistance --> dilate airway
100
What is the action of parasympathetic stimulation on airways?
Stimulation involves direct activation of MUSCARINIC receptors by Ach which contracts smooth muscle and increases resistance
101
What is the action of inflammatory mediators such as leukotrienes and histamine released during asthma attacks/allergix rxns on airways?
Cause bronchial smooth muscle constriction which increases airway resistance
102
True/False: Airway resistance can be affected by degree of expiratory effort
TRUE - to a degree
103
Describe flow rate during expiration
FLow rises to a high volume but then declines for the remainder of expiration
104
_______ results when intrapleural pressure equals or exceeds alveolar pressure, causing dynamic collapsing of the lung airways
Dynamic compression of the airways
105
What is the limiting factor in dynamic compression of the airways?
the effect that the increase in intrapleural P has on transpulmonary P along the airway
106
Describe the intrapleural pressure, alveolar pressure, and transpulmonary pressure in a lung pre-inspiration
intrapleural pressure will be negative, alveolar pressure in equilibrium with atm, transpulm P is positive and gradient is uniform [difference between alveolar and intrapleural pressure]
107
What happens to intrapleural pressure, alveolar pressure and transpulmonary pressure during inspiration?
Contraction of inspiratory muscles causes volume of thorax to increase. This increases lung volume which leads to decreases in alveolar pressure. The alveolar P becomes less than atmospheric pressure which creates a pressure gradient bringing O2 into the lung. With increasing lung volume, elastic recoil strength of the lung increases so intrapleural pressure becomes even more negative than at rest.
108
What happens at the end of the inspiration?
Intrapleural pressure is still more negative than preinspiration; alveolar pressure regains equilibrium with atmospheric pressure and transpulm pressure gradient once again uniform
109
What happens during forced expiration?
Intrapleural pressure increases dramatically, alveolar pressure becomes higher than atmospheric pressure, transpulm gradient no longer uniform
110
What happens to resistance close to the mouth during forced expiration?
intrapleural pressure actually becomes positive, decreasing airway diameter and increasing resistance
111
Recruitment (opening of previously closed capillaries), distention (increased caliber of already open capillaries) and expansion of lung volume all decrease ______
pulmonary vascular resistance
112
How did the Swan-Ganz catheter measure pulmonary vascular resistance?
It recorded the pulmonary artery wedge P by measuring the static fluid P in the pulmonary circuit [reflected left atrial P and total body fluid balance]
113
True/False: In mild exercise, there is a decrease in the regional differences of blood flow
True
114
In an upside down human, apical blood flow is ______ than basal blood flow
greater
115
Describe the distribution of blood flow in the lungs in terms of the relative alveolar, arterial and venous pressures when a person is standing.
In the apex of the lungs, the alveolar pressure is greater than the arterial (venous is lowest) - this can lead to compression of the capillaries and therefore blood flow is lowest in this area. Basically, apex is ventilated but not perfused. In the middle of the lungs, arterial pressure is greater than alveolar (venous is till the lowest) so blood flow is medium - driven by difference in arterial and alveolar [arterial increased because of gravity "waterfall effect." At the base of the lungs, arterial greatest, followed by venous and alveolar is least. This leads to the greatest blood flow in the lungs.
116
In hypoxia, do the smooth muscle walls of the lungs contract or relax? What is the effect of this and why?
Hypoxic vasoconstriction occurs in the lungs (contraction of smooth muscle). This local vasoconstriction redirects blood flow away from poorly ventilated, hypoxic regions of the lung to well-ventilated regions.
117
Nitrous oxide is derived from what amino acid?
L-arginine
118
True/False: NO is great for decreasing pulmonary hypoxic vasoconstriction in the real world
FALSE only works in the lab
119
What happens to pulmonary arterial pressure at high altitudes?
It increases due to generalized vasoconstriction - so someone who could breathe fine at sea level may be diagnosed with COPD at a higher level
120
Describe fetal pulmonary vascular resistance before and after birth.
Before birth, PVR is very high because of generalized hypoxic vasoconstriction so Q through fetal lungs is low. upon birth and first breath, alveoli are oxygenated and PVR decreases, so pulmonary Q increases and becomes equal to CO
121
True/False: Most people with issues with hypoxic vasoconstriction can take calcium channel blockers to treat these
FALSE ONLY HELPS 10%
122
Where does fluid leakage from capillaries travel?
It goes into the interstitium of alveolar walls via perivascular and peribronchial lymph nodes
123
In interstitial edema, transport of excess fluid goes to ______. When capacity of the lymphatics is exceeded, fluid pours into the _____.
hilar lymph nodes, alveoli [ interferes with gas exchange]
124
Describe neurogenic pulmonary edema and its affects on capillaries.
Increased intracranial pressure leads to increased pulmonary capillary pressure which causes trauma to capillaries and increased capillary permeability
125
What is the mechanism for high-altitude pulmonary edema?
Unknown, but does cause hypoxia-induced vasoconstriction at pre-capillary sites
126
In _________, there is an accumulation of proteinaceous fluid in the alveoli due to a number of causes which leads to a significant ________
adult respiratory distress syndrome (ARDS), V/Q mismatch
127
What are four causes of adult respiratory distress syndrome (ARDS)?
severe trauma, sepsis, pancreatitis and pneumonia (aspiration or community-acquired)
128
What is the best treatment for ARDS?
low tidal volume ventilation [ prevents trauma ]
129
ARDS has 60-70% mortality rate at 30 days. This rate is lower in ____ and higher in ______
trauma victims (tend to be yougner and healthier), alcohol abusers (immunosuppression)
130
A variant of ARDS is _____ which occurs with massive blood product transfusion, most commonly fresh frozen plasma
Transfusion-related acute lung injury (TRALI)
131
What is thought to be the mechanism for TRALI?
Development of anti-granulocyte antibodies that then attack recipient's granulocytes - initiates an inflammatory response in pulm capillaries
132
What are the symptoms of TRALI?
1-2 hours post transfusion: fever, tachycardia, tachypnea; pink, frothy sputum;
133
True/False: Other functions of pulmonary circulation include a reservoir for blood (due to decreased PVR) and filtration (small thrombi, WBCs)
true
134
True/False: Angiotensin converting enzyme is found in the small pits of capillary endothelial cells
True
135
______ is released during anaphylaxis and transferred to platelets in the lung
serotonin
136
______ keeps ductus arteriosus patent in fetus
prostaglandin E2
137
All prostaglandins cause platelet _____ and ______ in asthma
platelet aggregation, bronchoconstriction
138
The protein framework of lungs consists of collagen and elastin. This can be broken down by _____. _______ will act to stop that. An inherited disorder that causes emphysema in young, non-smokers is _________
trypsin, antitrypsin, alpha 1 antitrypsin deficiency
139
What part of the brain coordinates sensory info?
the brain stem
140
The ______ is located in the reticular formation, a poorly defined collection of neurons, and includes two groups: ______ and ______
medullary respiratory center, dorsal respiratory group, ventral respiratory group
141
The dorsal respiratory group is primarily responsible for ______; whereas the ventral respiratory group is primary responsible for _______
inspiration [generates basic rhythm for breathing]; expiration
142
Input to the dorsal respiratory group comes from which nerves? How do these nerves relay information?
a) vagus nerve - relays info from peripheral chemoreceptors and mechanoreceptors in the lung
b) glossopharyngeal nerve relays info from peripheral chemoreceptors
143
True/False: The ventral respiratory group is not active during normal, quiet breathing
True
144
The ____ is located in the ____ pons and _______ inspiration, producing a deep and prolonged inspiratory gasp known as ___
apneustic center, lower pons, stimulates, apneusis
145
The _____ center is located in the ____ pons and _____ inspiration and therefore regulates inspiratory volume and respiratory rate
pneumotaxic center, upper, inhibits inspiration
146
True/False: Hypoventilation (breath holding) is limited by the resulting increase in PCO2 and decrease in PO2.
true
147
The medullary respiratory system is located in the reticular formation below the ______ and contains the ______ which is an intrinsic respiratory rhythm generator
fourth ventricle, Pre-Botzinger complex
148
The Pre-Botzinger complex is found _____ to the Botzinger complex and ______ to the ventral respiratory group. It is located in the ___________ (RVLM)
inferior, superior, rostral ventrolateral medulla
149
In the Pre-Botzinger complex, crescendo of action potentials leads to stronger ______ muscle activity and once the action potentials cease the tone falls to pre-level
inspiratory
150
If the ______ in the medullary respiratory center is destroyed, this can lead to respiratory failure.
Nucleus ambiguus
151
When the pneumotaxic center turns off the inspiratory ramp, inspiration is shortened and therefore respiratory rate _____
increases
152
The nucleus ambiguus is the motor nucleus of the glossopharyngeal and vagus nerves, which terminate in the ______ close to the inspiratory center.
tractus solitarus
153
True/False: Ventilation in the normal quiet breathing state is achieved by active contraction of inspiratory muscles and passive relaxation of the chest wall and not by the medulla
TRUE
154
Transient apnea may be caused by a lesion in the ______ lobe
temporal
155
Permanent apnea involves the ______ and ______
lower pons, medulla (nucleus ambiguus)
156
________ are 10-20 second periods of apnea followed by equal periods of hyperapnea and are frequency seen in high altitude, severe heart disease, or severe neuro injury.
cheynes-stroke respirations
157
True/False: The Cortex can override the function of the brainstem within limits.
True
158
True/False: Voluntary hyperventilation can halve the PCO2 to the point of muscular tetany
true
159
The limbic system and hypothalamus play a role in affective states such as _____ and ____
fear, rage
160
Central chemoreceptors are located in the ______ lateral to pyramids and medial to CN 7 to 10 rootlets and in the ______ lateral to pyramids and medial to CN 12 rootlet
rostral zone, caudal zone
161
What change do chemical chemoreceptors respond to and how?
Central chemoreceptors respond to changes in [H+]. [H+] does not cross the blood brain barrier but CO2 does where it combines with H2O to produce H+ and HCO3-. Therefore, when chemical chemoreceptors sense an increase in [H+] in the CSF they stimulate hyperventilation to decrease PCO2
162
What is the result of rising arterial PCO2 on cerebral blood flow?
Cerebral vasodilation occurs which results in an increase in CO2 washout in brain PCO2 levels --> reduced brain acidification --> reduction in increased ventilatory drive from central chemoreceptors
163
The _______ is the point at which rhythmic ventilation ceases at a given PCO2
apneic threshold
164
True/False: The normal pH of CSF is less than the normal pH of arterial blood
TRUE - normally 7.32 - due to reduced protein in fluid and less buffering capacity
165
True/False: The change in CSF pH for a given pCO2 is much greater than with blood
true
166
If CSF pH is displaced for a prolonged period of time, a compensatory change in _______ occurs as a result of transport across the blood-brain barrier. ______ takes 2-3 days and is more rapid than it is for arterial systems
HCO3-; renal compensation takes 2-3 days
167
_______ are located in the bifurcation of the common carotid arteries=______ and above and below the arch of the aorta=__________
peripheral chemoreceptors, carotid bodies, aortic bodies
168
How do peripheral chemoreceptors react to changes in arterial PO2?
If there is a decrease in PO2 below 75mmHg, breathing rate is increased ; if there is an increase in PO2 it also stimulates an increase in breathing rate
169
True/False: The response of the peripheral chemoreceptors to CO2 is more important than the response of the central chemoreceptors
FALSE LESS IMPORTANT [ do respond to increases in CO2 tho]
170
How do peripheral chemoreceptors react to changes in arterial [H+]?
Changes in pH stimulate the carotid body peripheral chemoreceptors directly, independent of changes in PCO2 - when increased, hyperventilation induced
171
True/False: Peripheral chemoreceptors are responsible for all of the increase in ventilation in response to arterial hypoxemia
TRUE DAT
172
What happens to the peripheral chemoreceptor response in hypotension?
There is decreased blood flow (O2 delivery) to the carotid bodies and subsequently an increase in ventilation.
173
What are the four lung receptors?
lung stretch, irritant, J (juxtacapillary), joint and muscle
174
________ receptors are located between the airway epithelial cells and are stimulated by noxious substances
irritant
175
_______ are located in the alveolar walls, close to the capillaries. They are stimulated by engorgement of pulmonary capillaries, such as in left heart failure which leads to _______
J (juxtacapillary) receptors - rapid, shallow breathing
176
________ receptors are located in the smooth muscle of airways and when stimulated by distention of the lungs produce a reflex decrease in breathing frequency
lung stretch receptors
177
_______ receptors are activated during movement of the limbs are are involved in early stimulation of breathing during exercise
joint and muscle receptors
178
True/False: Pulmonary stretch receptor reflex is inactive in adults unless large tidal volumes are encountered
True
179
True/False: Transient bilateral blockage of vagus nerve affects respiratory rate/volume
FALSE does not
180
________ receptors respond to mechanical and chemical stimulation. These are an extension of irritant receptors whose responses include sneeze, cough, bronchoconstriction, and laryngeal spasm
Nasal and upper airway
181
_______ in intercostal muscles and diaphragm sense elongation and involves in the sensation of dyspnea
gamma system
182
How do arterial baroreceptors react to changes in BP [in terms of ventilation]?
An increase in BP leads to hypoventilation or apnea; whereas a decrease in BP leads to hyperventilation
183
True/False: Pain and heating of skin both lead to hypoventilation
FALSE both lead to hyperventilation. Pain causes apnea at first doe.
184
The most important factor in control of ventilation under normal conditions is _______
arterial pCO2
185
PO2 has little effect in day to day management of minute ventilation. When would ithave an effect?
high altitude ascent - large inc in Ve
186
Why would high FIO2 depress total ventilation rate in those with chronic lung disease?
Hypoxic ventilatory drive is very important for these individuals and CO2 retention is chronic
187
T/F: Hypoxemia has no effect on central chemoreceptors
True
188
T/F: IN the absence of peripheral chemoreceptors, hypoxemia stimulates respiratoryrate
FALSE causes respiratory depression [ unless grossly prolonged then can lead to acidosis and increase in VE]
189
Arterial pH falls with heavy exercise due to ______
lactic acidosis
190
Clubbing of fingernails indicates ____
hypoxia
191
A lession in the ______ and _______ would lead to cheyne-stokes respirations
diffuse cerebral cortex, diencephalon
