Mechanics Of Breathing Flashcards
(143 cards)
1
Q
Four key functions of the respiratory system
A
Exchange of gasses between the atmosphere and blood
Homeostatic regulation of body pH
Protection from inhaled pathogens
Vocalization
2
Q
Briefly describe exchange of gasses between the atmosphere and blood
A
The body brings in oxygen for distribution to the tissues and eliminates CO2 waste produced by metabolism.
3
Q
Briefly describe homeostatic regulation of body pH
A
The lungs can alter body pH by selectively retaining for secreting CO2
4
Q
Describe how the respiratory system protects from inhaled pathogens and irritating substances
A
The respiratory epithelium is well supplied with the defence mechanisms to trap and destroy potentially harmful substances before they can enter the body.
5
Q
What is vocalization
A
Air moving across vocal chord creates vibrations used for speech, singing and other forms of communication
6
Q
What is lost from the body through the respiratory system besides carbon dioxide
A
Water and heat
7
Q
How is flow in the respiratory system similar to the cardiovascular system
A
There’s an exchange of bulk flow of air between the environment and the interior air spaces of the lungs. It follows many of the same principles that govern the bulk flow of blood through the cardiovascular system.
8
Q
3 types of cells in the alveoli
A
- Type I alveolar cell for gas exchange
- Type II alveolar cells synthesize surfactant
- Alveolar macrophages ingest foreign material
9
Q
What principles govern bulk flow of air in the respiratory system
A
- Flow takes place from regions of high pressure to regions of low pressure.
- A muscular pump create pressure gradients.
- Resistance to airflow is influence primarily by the diameter of the tube through which air is flowing.
10
Q
Cellular respiration
A
The intracellular reaction of oxygen with organic molecules to produce carbon dioxide, water, and energy in the form of ATP.
11
Q
What is external respiration
A
The movement of gasses between the environment and the body cells
12
Q
When ventilation is a cycle between
A
Inspiration and expiration
13
Q
Air flows from regions of high
A
Pressure to regions of low pressure
14
Q
What is the difference between ventilation and respiration
A
Ventilation is the bulk flow exchange of air between that atmosphere in the lungs. Respiration is a movement a gasses between the environment and body cells.
15
Q
What does External respiration include
A
- Exchange of air between the atmosphere and the lungs
- The exchange of oxygen and carbon dioxide between the lungs and the blood.
- The transport of oxygen and carbon dioxide by the blood
- The exchange of gasses between blood in the cells.
16
Q
The respiratory system consist of
A
Structures involved and ventilation and gas exchange. These are: the conducting system, alveoli and the pulmonary capillaries, and bones and muscles of the thorax
17
Q
The upper respiratory tract
A
The mouth, nasal cavity, pharynx, and larynx.
18
Q
The lower respiratory tract consists of
A
The trachea, 2 primary bronchi, their branches and the lungs
19
Q
What is the relationship between the lungs, the pleura and the pleural fluid
A
The pleural fluid creates a moist and slippery surface so that the pleural membranes can slide across one another as the lungs move within the thorax. This helps prevent friction. It also holds the lungs tight against that thoracic wall. The cohesiveness of the fluid between the 2 pleural membranes helps the lung stick to the thoracic cage and holds them stretched and in a partially inflated state even at rest.
20
Q
How do type 2 cells help minimize the amount of fluid present in the alveoli
A
By transporting solutes, followed by water out of the alveolar air space.
21
Q
Describe what is physically happening during inspiration
A
In quiet breathing the diaphragm contracts and drops down toward the abdomen. The external intercostal and scalene muscles contract and pull the ribs outward and out. This broadens the rib cage and thoracic volume increases, pressure decreases, and air flows into the lungs.
22
Q
How do you calculate the partial pressure of one has in a mixture of gases
A
Pgas= Patm × % of gas
23
Q
What happens to the partial pressures of individual gasses if dry air is suddenly humidified
A
The pressure of water vapor dilutes the contribution of other gasses to the total pressure
24
Q
For gases, what happens to pressure and volume in a closed container
A
As volume decreases, pressure increases. There is an inverse relationship between pressure and volume.
25
How does the respiratory system create changes in volume
The muscle contractions increase the volume of the chest cavity
26
What happens to the diaphragm during inspiration
During inspiration the diaphragm contracts and becomes flat
27
Which muscles are contracting during and inspiration in quiet breathing
The inspiratory muscles consist of a external intercostal muscles, diaphragm, sternocleidomastoids and scalenes,
28
Which muscles are r used for contraction in active expiration
Internal intercostal muscles and abdominal muscles
29
Explain why puncturing the pleural membrane causes lung to collapse
The pleural cavity is normally at sub atmosphere pressure. So opening the pleural cavity to the atmosphere allows air to flow into the cavity. This causes the bond between the pleural membranes to break which normally holds the lung to the chest wall. The chest wall expands outward while the elastic lung collapses to an unstretched state.
30
Does a lung of high compliance require additional force to stretch it or is it easily stretched
It is easily stretched
31
Define compliance
The ability of the lung to stretch
| /_\ V/ /_\P
32
What is elastance
The ability to resist being deformed and the ability to return to its original shape when deformity force is removed
33
Does a high compliance lung always at high elastance? Explain.
False. Compliance is the reciprocal of elastance. A lung that stretches easily has probably lost its elastic tissue and will not return to its resting volume when stretching force is removed.
34
What happens to compliance and elastance in the disease state of emphysema
Elastin fibers of the lung are destroyed in this disease. This will cause high compliance and the lungs will stretch easily during inspiration. They also have decreased elastance, so they do not recoil to their resting position during expiration.
35
What happens to alveolar pressure to cause you to inhale
It decreases to about 1 mm Hg below atmospheric pressure with the increase in volume from the contraction of inspiratory muscles
36
What are some factors that create resistance to stretch in the lung
Surface tension from the fluid in the alveoli
37
What is the function of surfactant
It reduces surface tension of alveolar fluid and decreases resistance of the lung to stretch
38
What is surfactant
Are molecules that disrupt cohesive forces between water molecules by substituting themselves for water at the surface
39
According to the law of LaPlace, if 2 alveoli have equal surface tension, will the smaller one have a higher or lower internal pressure
Higher internal pressure
40
What happens to premature babies who have not produced surfactant
They have low compliance lungs and their lungs can collapse each time they exhale. They use a lot of energy to expand their collapse lungs with each breath. Because of this they develop newborn respiratory distress syndrome. They require rapid treatment or risk a 50 percent chance of dying, some require artificial ventilation.
41
Relationship between flow, pressure and resistance
Flow Is directly proportional to change in pressure and inversely related to resistance
42
3 factors to resistance
1. Systems length
2. The viscosity of the substance flowing through the system
3. The radius of the tubes in the system
43
What is the most significant factor of affecting resistance in the airways
The radius of the airways
44
What airway of the respiratory system is a site of variable resistance
Bronchioles because they are collapsible tubes
45
What happens to resistance and air flow when bronchioles constrict
Resistance increases and air flow decreases into the alveoli
46
```
Do the following dilate or constrict the bronchial diameter
CO2
HISTAMINE
EPINEPHRINE
PARASYMPATHETIC OUTPUT
```
Co2--> dilation
Histamine--> constriction
Epinephrine-->dilation
Parasympathetic output--> constriction
47
Total Pulmonary Ventilation
The volume of air moving in and out of the lungs in one minute . Aka minute volume. RR × Vt =TPV
48
Anatomic Dead Space
This is the conducting system part of the respiratory system where air enters, but is not involved with gas exchange with the blood
49
How is alveolar ventilation different from total pulmonary ventilation and which is most important
Alveolar ventilation is the volume of fresh air that reaches the alveoli each minute. This does not include dead space air. TPV includes dead space air. Alveolar ventilation includes is a more efficient measurement
50
The additional air inhaled after a normal inspiration
Inspiratory reserve volume
51
Residual volume
The minimum amount of air always present in the respiratory system after blowing out all you can
52
Tidal volume
The amount of air taken in during a single normal inspiration
53
The extra amount of air actively exhaled after a normal exhalation
Expiratory reserve volume
54
Explain how ventilation perfusion matching works when you are exercising
During exercise BP rises and the normally closed apical capillary beds open to ensure increased cardiac output be can fully oxygenated and meet metabolic demands. The body attempts to match air flow and blood flow in each section of the lung by regulating the diameter of arterioles and bronchioles
55
By what mechanism do gases move between alveoli and the plasma
Gas diffuses down its partial pressure gradient from alveoli into capillaries until equilibrium is met
56
4 factors that affect rate of diffusion of gases
1. Surface area
2. Concentration gradient
3. Barrier permeability
4. Diffusion distance
57
Formula that relates factors that affect rate of diffusion (FICKs)
Diffusion rate
58
What is the primary factor influencing gas exchange
The concentration gradient
59
What 3 factors determine how much gas will dissolve in a liquid
1. Pressure gradient
2. Solubility of the gas in liquid
3. Temperature
60
If liquid is exposed to PCO2 of 100 mmHg and a PO2 of 100 mmHg, equal amounts of oxygen and carbon dioxide will dissolve in the liquid
False
61
Is O2 or CO2 more soluble in body fluids
CO2
62
Gases move between liquid and gases phases until what is reached
Equilibrium
63
The more soluble a gas is the ________the partial pressure needed to force the gas into solution
Less
64
What are the partial pressures of the following at normal atm pressure during normal breathing
1. PO2 atm
2. PCO2 atm
3. PO2 alv
4. PCO2 alv
1. 160 mmHg
2. 0.25 mmHg
3. 100 mm Hg
4. 40 mmHg
65
During normal breathing partial pressures in alveoli remain constant, why
The amount of Oxygen that enters the alveoli with each breath is roughly = to the amount of oxygen that enters the blood. The amount of fresh air that enters the lungs with each breath is only a little more than 10% of the total lung volume at the end of inspiration. Due to the air in the dead space there's a constant partial pressure of O2.
66
Partial pressure of the following at sea level
P02--> alveoli, arterial, resting cells,venous blood
PC02--> alveoli, arterial, resting cells,venous blood
P02--> alveoli 100, arterial 100, resting cells 40, venous blood 40
PC02--> alveoli 40, arterial 40, resting cells 46, venous blood 46
67
How does P02 change with increased alveolar ventilation or decreased alveolar ventilation
Increased P02/decreased P02
68
How does PC02 change with increased alveolar ventilation or decreased alveolar ventilation
Decreased PC02/ increased PC02
69
Diagram a single alveolus and label cells that are found on the walls and associated
Liquid layer, alveolar air space. Basal lamina, ma macrophages, endothelial cells if capillaries, type I and II alveolar cells, respiratory membrane
70
What 2 cell layers must gases cross to go from alveoli to plasma
Alveolar cells and endothelial cells of capillary
71
What additional layer must gases pass from alveoli to blood
Basement membrane
72
What are the components of the respiratory membrane
Type I alveolar cells, basal lamina, endothelial cells of capillary
73
Explain how emphysema can result in a loss of alveolar surface area
Emphysema is most often caused by cigarette smoking. The irritating effect of smoke chemicals and tar in the alveoli activates alveolar macrophages that release elastance and other proteomic enzyme. These destroy elastic fibers of the lung and induce apoptosis of cells, breaking down the walls of the alveoli. The result is high compliance and low elastic recoil with fewer and larger alveoli and less surface area for gas exchange.
74
Explain how fibrotic lung disease can cause decreased oxygen exchange between alveoli and the blood
Scar tissue thickens the alveolar wall.
| Diffusion of gases through the scar tissue is much slower than normal. This decreases oxygen diffusion into the blood
75
What is pulmonary edema and how is it caused and how does it alter gas exchange
It is an accumulation of interstitial fluid in the lungs. This increases the diffusion distance between lung and blood and slows gas exchange, leading to lower P02 levels
76
What is asthma
An obstructive lung disease that causes inflammation of the airways--> bronchoconstricion and airway edema. This causes increased airway resistance to airflow and decreased airway ventilation. Leading to decreased 02 in lungs and diffusion rate of 02 across the alveoli and capillaries.
77
Explain how breathing at high altitude results in lower 02
The partial pressure of 02 decreases along with atmospheric pressure as you move from sea level to higher altitudes. There is lower oxygen concentration at higher altitudes
78
Where is most of the arterial 02 found
98% is in hemoglobin of RBC
79
How many protein subunits are composed Hb molecules of
4
80
(Hemoglobin molecules)This group is based around what element and is it a strong bond
Iron/binds weakly to oxygen
81
Hb bound to 02 is
Oxyhemoglobin
82
As dissolved 02 diffuses into RBCs, what happens to the P02of the surrounding plasma
It decreases
83
When 02 binds to Hb then ________02 can diffuse from alveoli into plasma.
More
84
Percent Saturation of hb
The amount of 02 bound to Hb at any given P02
85
At 100%, all possible binding sites are
Bound
86
At the cells, dissolved 02 in the plasma_______ the cells. This disturbs the __________ so 02 dissociated from Hb, obeying the Law of ____
Enters
Equilibrium
Mass
87
In the tissues, the P02 of the plasma reflects the P02 of the__________
Cells
88
In the oxygen hemoglobin disociation curve the ____________determines the ____________
% P02
| Saturation of Hb
89
Below P02 of 60 mmHg, where curve is steeper, small changes in P02 cause relatively ________ release of 02 from Hb
Large
90
An increase in pH___________ Hb's affinity for 02
Increase
91
An increase in temperature__________ Hb's affinity for 02
Decreases
92
An increase in PC02___________ Hb's affinity for 02
Decreases
93
An increase in 2,3-DPG___________ Hb's affinity for 02
Decreases
94
A left shift in the curve indicates___________ binding affinity for 02
Increased
95
A right shift in the curve indicates___________ binding affinity for 02
Decreased
96
Under what conditions is cellular production of 2,3 DPG increased
Chronic hypoxia or extended periods of low 02
97
Fetal hb
It has 2 gamma chains instead 2 beta chains. This change in hb structure changes its 02 binding affinity. This enhances the ability of it to bind oxygen in the low oxygen environment of the placenta
98
Where would you expect to see the highest affinity
| Active tissue or lungs
In the lungs
99
What are the 3 ways C02 is transported in the blood
1. C02 dissolved in plasma (7%)
2. HbC02, carbaminohemoglobin (23%)
3. HC03, bicarbonate ion (70%)
100
The name of hb bound to C02 is
HbC02, carbaminohemoglobin
101
Equation for C02 and bicarbonate, what enzyme catalyzes it
C02 +H20<===>H +HC03-
| Carbonic anhydrase
102
What happens to pH when C02 levels rise
pH decreases
103
Compare the function of the dorsal and ventral respiration groups of neurons in the medulla
Dorsal control mostly muscles of inspiration, ventral controls Respiratory rhythm, control for active expiration
104
List the 3 chemical factors that affect ventilation. Where are the sensory receptor located for each
1. C02-->medullary central chemoreceptors (BBB), peripheral chemoreceptors Carotid (primary) and aortic bodies in the arteries
2. 02--> peripheral chemoreceptors in carotid and aortic bodies of arteries
3. pH--> peripheral chemoreceptors in carotid and aortic bodies of arteries
105
What is the primary stimulus for changes in ventilation
Carbon dioxide
106
Explain the strategic significance of the location of the peripheral chemo receptors
The chemoreceptors for 02 and C02 are strategically associated with the arterial circulation. If too little 02 is present in arterial blood destined for the brain and other tissues, the rate and depth of breathing increases. If the rate of C02 production by the cells exceeds the rate of C02 removal by the lungs, arterial PCO2 increases and ventilation is intensified to match C02 removal to production. If plasma pH decreases, aortic and carotid gliomas cells increase ventilation
107
Where are the limited ranges of the chemical signals the stimulate peripheral chemoreceptors receptor
P02 less than 60 mmHg
Decreased pH
Increased PC02
108
How are central chemoeceptors able to respond to elevated blood PC02
Central receptors in the Medulla mediate ventilation changes in response to pH. A decrease in PC02 will trigger a decrease in ventilation.
109
A decrease and pH will trigger what to ventilation
Increase in ventilation
110
A decrease in arterial PO2 below 60 mmHg will trigger what to ventilation
Increase in ventilation
111
An increase in PC02 will cause what to happen to the ph and this will trigger a 2-3 acidosis to respond a/an ___________ in ventilation
Decrease in pH, increase in ventilation
112
The upper respiratory tract includes
Nasal cavity, larynx, mouth,pharynx
113
Pulmonary ventilation refers to the
Pulmonary ventilation refers to the movement of air into and out of the lungs
114
Alveolar ventilation refers to
Movement of air into and out of the alveoli
115
The sites of gas exchange within the lungs are
Alveoli
116
Type I alveolar cells allow rapid
Diffusion of gasses through their thin membranes
117
When the diaphragm and external intercostals muscles contract
The volume of the thorax increases
118
In quiet breathing, inspiration involves _______and expiration is_______
Muscular contractions, passive
119
If a student inhales as deeply as possible and blows the air out until he cannot exhale anymore, the amount of air that he expelled is
Vital capacity
120
Flow of air is directly proportional to_______________ and flow_______________ as resistance of the system ____________
A pressure gradient
Decreases
Increases
121
Histamines primary role in the respiratory system is as a
Bronco constrictor
122
Damage to the type II cells of the lungs would contribute to
Alveolar collapse
123
The partial pressure of oxygen in the arterial blood is approximately
100
124
The partial pressure of carbon dioxide in the cells of peripheral tissue is approximately
46
125
Of the factors that influence diffusion of respiratory gasses the most variable and therefore important factor to consider is the
Concentration gradient or partial pressure difference
126
At a PO2 of 70 mmHg, normal temperature and ph, hemoglobin is ________% saturated with oxygen
Over 90%
127
What would make the oxygen hemoglobin curve shift right
* Oxygen leaves hemoglobin-->lower affinity
* Increased temperature
* Increased CO2
* Decreased pH--> increased H+ concentration
* 2,3DPG--> Hypoxia
128
What would make the oxy hemoglobin curve shift left
```
Oxygen loads on to hemoglobin-->higher affinity
• Decrease temperature
• Decreased carbon dioxide
• Increased PH
• Gamma globin/fetal hemoglobin
```
129
Most of the carbon dioxide in the blood is transported as
Bicarbonate ions
130
Most important chemical regulator of respiration is
Carbon dioxide
131
The expiratory neurons control the
Abdominal muscles and internal intercostals
132
The inspiratory neurons control the
Diaphragm and external intercostals
133
The disease most closely associated to a decrease surface area for gas exchange is
Emphysema
134
Alexandra is breathing in a gas composition that contains an increased concentration of C02. How would the pulmonary arteries react to this and why
Constrict to decrease blood flow through the alveoli
135
Systemic arterioles constrict and pulmonary arterial dilate when
P02 increases
136
Bronchioles and systemic arterioles dilate when
PC02 increases
137
Systemic arterioles dilate and pulmonary arterial constrict
P02 decreases
138
Bronchioles and systemic arterioles constrict when
PC02 decreases
139
Where does the change for CO2 and 02 take place once in circulation
C02 changes at the lungs and 02 at the tissues, otherwise constant in circulation
140
Cooperative binding of oxygen
The 1st oxygen binds and causes a 3-D shape change in the globin chains that facilitate the binding of the next oxygen and so on
141
What happens when there is a lot of C02 in the plasma
When there is a lot of carbon dioxide it changes the shape of hemoglobin and throws oxygen off. This reduces the affinity for oxygen.
142
The contraction of the inspiratory muscles occurs in response to output from the __________ and ________
Pons and medulla
143
Hemoglobin acts as a buffer to
H+, soaks up hydrogen to maintain a pH within set limits
