Lesson 13/14 Exam 5 Flashcards
1
Q
breathing depends on
A
repetitive stim of skeletal muscles from brain
2
Q
breathing will cease if
A
spinal cord is severed high in neck
3
Q
what are the two levels of the brain where breathing is controlled
A
- cerebral and conscious
- unconscious and automatic
4
Q
brainstem respiratory centers (2)
A
- automatic unconscious breathing
- controlled by respiratory centers in reticular formation
5
Q
what are the two pairs of respiratory centers in the medulla oblongata
A
- ventral respiratory group
- dorsal respiratory group
6
Q
ventral respiratory group (3)
A
- primary generator of the respiratory rhythm
- reverberating circuits I neurons and E neurons
- 12 breaths per minute
7
Q
dorsal respiratory group (4)
A
- inspiratory center stims inspiratory breathing
- functions in both quiet and forced breathing
- modifies the rate and depth of breathing
- receives influences from external sources
8
Q
what are the input receptors to the respiratory centers
A
- central chemoreceptors
- peripheral chemoreceptors
- stretch receptors
- irritant receptors
9
Q
central chemoreceptors
A
- brainstem neurons respond to changes in pH of CSF
- regulate respiration to maintain stable pH
- ensure stable CO2 levels in blood
10
Q
pH of CSF reflects the ____ level in blood
A
CO2
11
Q
peripheral chemoreceptors
A
- located in carotid and aortic bodies
- respond to O2 and CO2 content and pH of blood
12
Q
stretch receptors
A
- smooth muscle of bronchi and bronchioles and the visceral pleura
- respond to inflation of lungs
- inflation (Hering-Breuer) reflex
13
Q
inflation (Hering-Breuer) reflex
A
- triggered by excessive inflation
- protective reflex inhibits inspiratory neurons and stops inspiration to stop excessive inflation/stretching of lung tissue
14
Q
irritant receptors
A
- nerve endings amid epithelial cells of the airway
- trigger protective reflexes
- respond to foreign bodies
15
Q
examples of what irritant receptors respond to
A
- smoke
- dust
- pollen
- chemical fumes
- cold air
- excess mucus
16
Q
what are the protective reflexes triggered by irritant receptors
A
- bronchoconstriction
- shallower breathing
- breath holding
- coughing
17
Q
voluntary control over breathing originates in
A
motor cortex of frontal lobe of cerebrum
18
Q
what does the voluntary control of breathing do in regards to the nervous system
A
send impulses down corticospinal tracts to respiratory neurons in spinal cord bypassing the brainstem
19
Q
breaking point
A
when CO2 levels rise to a point where automatic controls override one’s voluntary will
20
Q
respiratory airflow is governed by
A
the same principles of flow, pressure, and resistance as blood flow
21
Q
the flow of a fluid is ___ to the pressure difference between two points
A
directly proportional
22
Q
the flow of fluid is ____ to the resistance
A
indirectly proportional
23
Q
atmospheric pressure
A
the weight of the air above us
24
Q
what is the atmospheric pressure at sea level
A
- 760 mmHg
- 1 atm
25
_____ atmospheric pressure at higher elevations
lower
26
intrapulmonary pressure
air pressure within lungs
27
intrapulmonary pressure changes with ___
lung volume
28
Boyle's Law
- governs air flow into and out of the lungs
- at constant temp the pressure of a given quantity of gas is inversely proportional to its volume
29
if lung volume increases what happens to intrapulmonary pressure
it decreases
30
if the pressure inside the lungs falls below atm pressure
air moves into the lungs
31
if lung volume decreases intrapulmonary pressure
increases
32
if lung pressure rises above atm pressure
air moves out of the lungs
33
during inspiration what happens
the lungs expand and follow the expansion of the thoracic cage because of intrapleural pressure
34
intrapleural pressure
slightly negative pressure that exists between the two pleural layers
35
recoil of lung tissue and tissues of the thoracic cage causes
lungs and chest wall to be pulling in opposite direction
36
about ____ if intrapleural pressure results from layers of pleura staying together
-5 cm H2O
37
in quiet breathing
thoracic cage increases only a few mm in each direction
38
during inspiration, the visceral pleura does what?
stretches the alveoli near surface of lungs which are coupled to deeper alveoli which get pulled too
39
as alveoli increases in volume
the intrapulmonary pressure drops below atm pressure
40
what is another force that expands lungs during inspiration?
warming of inhaled air
41
Charles's Law
the volume of a gas is directly proportional to its absolute temp
42
on a cool day 60°F air will do what during inspiration
increase its temp by 39°F
43
inhaled air is warmed to _____ by the time it reached the alveoli
99°F
44
inhaled volume of 500ml will expand to 536ml. what does this do to the lungs?
contribute to inflation of the lungs
45
passive process in quiet expiration is achieved by
mainly by elastic recoil of thoracic cage which compresses the lungs
46
expiration does what to intrapulmonary pressure
raises to about +1cm H2O
47
in a normal lung the intrapulmonary pressure is always
negative in both inspiration and expiration
48
pneumothorax (3)
- presence of air in the pleural cavity
- thoracic wall is punctured
- inspiration sucks air through the wound into pleural cavity
49
what happens to the potential space during a pneumothorax
becomes an air-filled cavity causing the loss of negative intrapleural pressure allowing the lung to recoil and collapse
50
atelectasis
collapse of part or all of a lung
51
what can a collapsed lung result from (physiological)
from an airway obstruction as blood absorbs gases from the alveoli causing a decrease in alveolar volume and subsequent alveolar collapse
52
a collapsed lung can be caused by (diseases) (4)
- lung tumor
- aneurysm
- swollen lymph nodes
- aspirated objects into the airway
53
what two factors influence airway resistence
bronchiole diameter and pulmonary compliance
54
bronchodilation
increase in diameter of bronchus or bronchiole
55
bronchoconstriction
decrease in diameter of bronchus or bronchiole
56
pulmonary compliance (2)
- ease with which the lungs can expand
- change in long volume relative to a given pressure change
57
pulmonary compliance is reduced in
degenerative lung disease in which the lungs are stiffened to scar tissue
58
what are two examples of degenerative lung diseases where the tissue is turned to scar tissue
- TB
- black lung disease
59
pulmonary compliance is limited by
surface tension of water inside alveoli
60
what does surfactant do in the alveoli
disrupts hydrogen bonds between water molecules and thus reduced surface tension making ti easier to fill with air
61
infant respiratory distress syndrome (IRDS)
premature babies lacking surfactant are treated with artificial surfactant until they can make with own
62
only about ____ of air fills the conducting zone of the airway
150ml
63
anatomical dead space
the space in the conducting zone where there is no gas exchange
64
the anatomical dead space can be altered by ______ which increases what?
- sympathetic dilation
- flow into the lungs
65
spirometry
measuring pulmonary ventilation
66
what aid in the diagnosis of and assessment of restrictive/obstructive lung disease
spirometry
67
restrictive disorders of the lungs (2)
- reduction in pulmonary compliance and limit how much lungs can inflate
- any disease that produces pulmonary fibrosis
68
black lung and TB are what kind of lung disease
restrictive
69
obstructive disorders of the lungs (2)
- interfere with airflow by narrowing or blocking the airway
- make it harder to inhale or exhale a given amount of air
70
asthma and chronic bronchitis are examples of what kind of lung disease
obstructive
71
____ combines elements of both restrictive and obstructive disorders of the lungs
emphysema
72
eupnea
relaxed, quiet breathing
73
apnea
temporary cessation of breathing
74
dyspnea
- labored, gasping breathing
- shortness of breath
75
hyperpnea
increase rate and depth of breathing in response to exercise, pain, or other condition
76
hyperventilation
increase pulmonary ventilation in excess of metabolic demand
77
hypoventilation
reduced pulmonary ventilation leading to an increase in blood CO2
78
Kussmaul respiration
deep, rapid breathing often induced by acidosis or diabetes-related ketoacidosis
79
atmospheric air contains (4)
- 78.6% nitrogen
- 20.9% oxygen
- 0.04% carbon dioxide
- 0-4% water vapor depending on temp and humidity
80
atmospheric air contains minor amounts of what? (5)
- argon
- neon
- helium
- methane
- ozone
81
dalton's law
total atmospheric pressure is the sum of the contributions of the individual gases
82
partial pressure
separate contribution of each gas in a mixture
83
how is air humidified during inspiration? how much is it humidified by the time it reaches the alveoli?
- contact with mucous membranes
- 10x
84
the composition of inspired air and alveolar air differ because of what three influences?
- air is humidified by contact with mucous membranes
- alveolar air mixes with residual air
- alveolar air exchanges O2 and CO2 with blood
85
the partial pressure of O2 in alveolar air is ____ that of inspired air
65%
86
the partial pressure of CO2 in alveolar air is ____ (higher/lower) than that of inspired air
130x
87
alveolar gas exchange
- the movement of O2 and CO2 across the respiratory membrane
- air in the alveolus is in contact with a film of water covering the alveolar epithelium
88
for oxygen to get into the blood what must happen?
it must dissolve in the water covering the alveolar epithelium and pass through the respiratory membrane separating the air from the bloodstream
89
for carbon dioxide to leave the blood what must happen
it must pass the other direction as O2 and then diffuse out of the water film into the alveolar air
90
gas diffuses...until...
down their own concentration gradient until the partial pressure of each gas in the air is equal to its partial pressure in the water
91
henry's law
at the air-water interface for a given temp the amount of gas that dissolved in the water is determined by its solubility in water and its partial pressure in air
92
the greater the partial pressure of O2 in the alveolar air
the more O2 the blood picks up
93
since the blood arriving at the alveolus has a higher ppCO2 than air what happens
blood releases CO2 into the air
94
the efficiency in unloading CO2 and loading O2 on the erythrocytes depends on
how long an RBC stays in alveolar capillaries
95
how much time is required to reach equilibrium of O2 and CO2 pp
0.25 sec
96
at rest how much time do RBCs stay in the alveolar capillaries
0.75 sec
97
in strenuous exercise how long do RBCs stay in the alveolar capillaries
0.3 sec
98
each gas in an air mixture acts (independently/dependently) of the other gases in the mixture
independently
99
what variables affect alveolar gas exchange (5)
- pressure gradients of the gases
- solubility of the gases
- membrane surface area
- membrane thickness
- ventilation-perfusion coupling
100
what is the normal ppO2 in alveolar air vs in the blood
104mmHg in alveolar air and 40mmHg in blood
101
what is the normal ppCO2 in alveolar air vs in the blood
46mmHg in the blood and 40mmHg in alveolar air
102
pressure gradients of gases differ when (2)
- at higher altitudes
- hyperbaric oxygen therapy
103
at high elevations what happens to pp of atm gases? pressure gradient of oxygen?
- atm: lower
- O2: lower so less diffuse into blood
104
hyperbaric oxygen therapy
treatment of oxygen at greater than 1 atm of pressure
105
what happens to the gradients of oxygen in hyperbaric oxygen therapy
larger gradient so more oxygen diffuses into the blood
106
what is hyperbaric oxygen therapy used to treat
- gangrene
- CO poisoning
107
by the time blood reaches the left atrium what is the ppO2? what is it caused by?
- 95mmHg
- mixing of oxygenated blood from the pulmonary vein with deoxygenated blood from the bronchial vein
108
what are the pp of O2 and CO2 of blood when it reaches the tissues
- O2: 95mmHg
- CO2: 40mmHg
109
what is the ppO2 and ppCO2 in the tissue?
- O2: 40 mmHg
- CO2: 46mmHg
110
what happens during gas exchange in tissues
O2 is driven to tissue while CO2 is driven to blood so that venous blood leaving will have ppO2 of 40mmHg and ppCO2 of 46mmHg
111
CO2 if ___ as soluble as O2
20x
112
why are equal amounts of O2 and CO2 exchanged across the respiratory membrane
because CO2 is much more soluble and diffuses more rapidly
113
what three diseases of the lungs decrease surface area for gas exchange?
- emphysema
- lung cancer
- TB
114
what is the surface area of alveoli across the lungs
70m^2
115
the respiratory membrane is hoe thick?
only 0.5um
116
when membranes fo rgas exchange are thicker what happens?
gases have to travel farther between blood and air and cannot equilibrate fast enough to keep up with blood flow
117
what two diseases of the lungs thicken the respiratory membrane
- pulmonary edema
- pneumonia
118
ventilation perfusion coupling
- air flow and blood flow are matched to each other
- gas exchange requires both good perfusion and good ventilation of the capillaries
119
_____ change diameter depending on air flow to an area of the lungs
pulmonary blood vessels
120
_____ change diameter depending on blood flow to an area of the lungs
bronchi
121
gas transport
process of carrying gases from the alveoli to the systemic tissues and vice versa
122
arterial blood carries ____ of O2
20ml/deciliter
123
what are the two ways O2 is transported in the blood and what percentage O2 moves that way?
- 98.5% bound to hemoglobin
- 1.5% dissolved in plasma
124
how many components are there in a hemoglobin molecule?
four
125
what are the two parts of each component in hemoglobin?
- globin (protein) chain
- heme group
126
each heme group can bind ___ O2 to what?
- one
- a ferrous group (Fe2+)
127
oxyhemoglobin
O2 bound to hemoglobin
128
deoxyhemoglobin
hemoglobin with no O2
129
oxyhemoglobin dissociation curve
illustrates relationship between hemoglobin saturation and ambient ppO2
130
is the hemoglobin dissociation curve linear?
no
131
what happens to O2 saturation at low ppO2
curve rises slowly then rapid increase in oxygen loading as ppO2 rises farther
132
why is there an observed rapid increase in O2 loading at low ppO2?
because when hemoglobin binds each other oxygen it makes it easier to bind the next one
133
what happens to O2 saturation when there is a high ppO2
the curve levels off because hemoglobin approaches 100% saturation and cannot load much more O2
134
what are the three forms in which CO2 is transported and what percentage of CO2 is transported that way?
- 90% bicarbonate
- 5% carbaminohemoglobin
- 5% dissolved gas
135
what is the reaction that changes CO2 to bicarbonate
CO2 + H2O -> H2CO3 -> HCO3- + H+
136
where does the bicarbonate reaction occur?
inside the erythrocytes
137
carbaminohemoglobin
CO2 bound to hemoglobin
138
does CO2 compete with O2 to bind to hemoglobin? why?
no because they bind to different moieties
139
what are the relative amounts of CO2 exchanged between the blood and alveolar air?
- 70% carbonic acid
- 23% carbaminohemoglobin
- 7% dissolved in plasma
140
what is the hardest form of CO2 in the body to get CO2 from?
bicarbonate
141
carbon monoxide (CO)
colorless, odorless gas in cigarette smoke, engine exhaust, and fumes from gas furnaces
142
does CO compete with O2 to bind? why?
yes because it binds to the iron in hemoglobin where O2 binds
143
carboxyhemoglobin
carbon monoxide bound to hemoglobin
144
CO binds up to ____ tightly as O2
210x
145
what is the percentage of CO bound to hemoglobin in a non-smoker?
less than 1.5%
146
what is the amount of CO bound to hemoglobin in heavy smokers?
10%
147
what are the treatments for CO poisoning?
- pure oxygen
- hyperbaric oxygen therapy
- blood transfusion
148
systemic gas exchange
unloading of O2 and loading of CO2 at systemic capillaries
149
carbonic anhydrase
catalyzes reaction to bicarbonate and hydrogen ions
150
chloride shift
bicarbonate pumped out of RBC in exchange for chloride ion from plasma
151
what performs the chloride shift?
chloride-bicarbonate exchanger (antiport protein)
152
what is the purpose of the chloride shift
- keep the carbonic anhydrase reaction going
- H+ binds to hemoglobin
153
how is hemoglobin made to let go of O2 during oxygen unloading
- H+ binding to HbO2 reduced its affinity for O2
- O2 moving down its pressure gradient
154
HbO2 arrives at systemic capillaries ___ saturated and leaves ___ saturated
- 97%
- 75%
155
utilization coefficient
the giving up of 22% of O2 load by hemoglobin during oxygen unloading
156
what are the three steps of CO2 unloading in the lungs
- as Hb loads O2, H+ affinity decreases and binds to HCO3-
- reverse carbonic anhydrase
- reverse chloride shift
157
what is a reverse chloride shift
- HCO3- diffuses back into RBC in exchange for Cl-
- free CO2 is generated and diffuses into alveolus to be exhaled
158
hemoglobin unloads O2 to match
metabolic needs
159
four factors that adjust rate of O2 unloading to match need: ambient ppO2
- active tissue has low ppO2
- O2 released from Hb
160
what are the four factors that adjust rate of O2 unloading to match need?
- ambient ppO2
- temp
- ambient pH
-BPG
161
four factors that adjust rate of O2 unloading to match need: temperature
active tissue had high temp and promotes O2 unloading
162
four factors that adjust rate of O2 unloading to match need: ambient pH
active tissue has high CO2 which lowers pH and promotes O2 unloading
163
what is it called when active tissue has high CO2 which lowers pH and promotes O2 unloading
the bohr effect
164
four factors that adjust rate of O2 unloading to match need: BPG
RBCs produce biphosphoglycerate which binds to Hb and promotes O2 unloading
165
what raises BPG levels?
- high body temp
- thyroxine
- GH
- testoterone
- epinephrine
166
higher temp causes a shift to the ___ of the O2 dissociation curve
right
167
lower temp causes a ____ shift in the O2 dissociation curve
left
168
shift to the right of the O2 dissociation curve causes ___ and a shift to the left causes ____
- more O2 release from Hb
- less O2 release from hemoglobin
169
lower pH shifts the O2 dissociation curve to the
right
170
higher pH shifts the O2 dissociation curve to the
left
