Lesson 13-14a Part 2 - Respiratory System Flashcards
(173 cards)
1
Q
breathing depends on…
A
repetitive stimulation of skeletal muscles from the brain
2
Q
breathing is controlled at two levels of the brain
A
- one is cerebral and conscious
- other is unconscious and automatic
3
Q
automatic, unconscious breathing is controlled by…
A
respiratory
4
Q
two pairs of respiratory centers are located where?
A
medulla oblongata?
5
Q
which respiratory center is the primary generator of the respiratory rhythm?
A
ventral respiratory group (VRG)
6
Q
where is the ventral respiratory group (VRG) located?
A
medulla oblongata
7
Q
the ventral respiratory group (VRG) is a collection of reverberating circuits of…
A
- inspiratory (I) neurons
- expiratory (E) neurons
8
Q
what rhythm does the VRG produce?
A
12 breaths per minute
9
Q
the dorsal respiratory group (DRG) is also called…
A
the inspiratory center
10
Q
what does the inspiratory center stimulate?
A
inspiratory muscles
11
Q
which respiratory group functions in both quiet and forced breathing?
A
dorsal respiratory group (DRG)
12
Q
the dorsal respiratory group (DRG) modifies what? how?
A
(1) the rate and depth of breathing by (2) affecting the VRG
13
Q
the dorsal respiratory group receives influence from…(4)
A
external sources like the pons, medulla, receptors in the lungs, and higher brain centers
14
Q
central chemoreceptors
A
brainstem neurons that respond to changes in pH of cerebrospinal fluid (CSF)
15
Q
the pH of cerebrospinal fluid reflects what?
A
the CO2 level in the blood
16
Q
the lower the pH in the CSF the……in blood?
A
more CO2 in blood
17
Q
central chemoreceptors regulate respiration to maintain…(2)
A
stable pH/stable CO2 levels in blood
18
Q
where are peripheral chemoreceptors?
A
carotid and aortic bodies
19
Q
what do peripheral chemoreceptors respond to? (3)
A
O2 and CO2 content and the pH of blood
20
Q
stretch receptors are located where in the lungs? (2)
A
- smooth muscle of bronchi and bronchioles
- visceral pleura
21
Q
what do stretch receptors in the lungs respond to?
A
inflation of the lungs
22
Q
inflation (Hering-Breuer) reflex
A
protective reflex that inhibits inspiratory neurons and stops inspiration to stop excessive inflation/stretching of lung tissue
23
Q
what is the Hering-Breuer reflex triggered by?
A
excessive inflation
24
Q
irritant receptors
A
nerve endings amid the epithelial cells of the airway
25
irritant receptors respond to (6)
- smoke
- dust
- pollen
- chemical fumes
- cold air
- excess mucus
26
irritant receptors trigger protective reflexes such as...(4)
- bronchoconstriction
- shallower breathing
- breath-holding
- coughin
27
apnea
breath-holding
28
where does voluntary control over breathing originate?
in the motor cortex of the frontal lobe of the cerebrum
29
what does the motor cortex of the frontal lobe of the cerebrum send?
impulses down corticospinal tracts to respiratory neurons in the spinal cord, bypassing the brainstem
30
the breaking point
when CO2 levels rise to a point where automatic controls override one's voluntary will
31
respiratory airflow is governed by...
the same principles of slow, pressure, and resistance as blood flow
32
the flow of a fluid is _____ proportional to the pressure difference between two points
directly
33
the flow of fluid is _____ proportional to the resistance
inversely
34
atmospheric (barometric) pressure
the weight of the air above us
35
where is atmospheric pressure lower?
higher elevations
36
intrapulmonary pressure
air pressure within the lungs
37
intrapulmonary pressure changes with lung volume according to what law?
Boyle's law
- P = 1/V
38
Boyle's Law
at a constant temperature, the pressure of a given quantity of gas is inversely proportional to its volume
- P = 1/V
39
if the lungs contain a quantity of gas, and the lung volume increases, what happens to internal pressure?
it falls
40
what happens if the intrapulmonary pressure falls below atmospheric pressure?
air moves into the lungs
41
what happens if intrapulmonary pressure rises above atmospheric pressure?
air moved out of the lungs
42
during inspiration, the lungs expand and...
follows the expansion of the thoracic cage due to the intrapleural pressure
43
intrapleural pressure
the slightly negative pressure that exists between the two pleural layers (parietal and viseral)
44
what causes the lungs and chest wall to be pulled in opposite directions? (2)
(1) recoil of lung tissue and (2) tissues of the thoracic cage
45
the potential space between the parietal and visceral pleurae contains?
a small amount of watery serous fluid called pleural fluid
46
how do the layers of the pleura stay together?
cohesion of water
47
what happens to the pleura when the ribs swing upward/outward during inspiration?
the pleura follows!
48
in quiet breathing , the thoracic cage moves a few _____ in each direction, which is enough to increase its volume by 500ml
mm (millimeter)
49
the _____ pleura clings to and follows the _____ pleura
visceral, parietal
50
what happens when the visceral pleura stretches?
the alveoli near the surface of the lungs stretches, and because they are coupled to deeper alveoli they got pulled too
51
as alveoli increase volume, the ______ (______) pressure drops below atmospheric pressure
intrapulmonary (alveolar)
52
another force that expands lungs is...
the warming of inhaled air
53
Charles's Law
the volume of a gas is directly proportional to its absolute temperature
54
is expiration a passive or active process in quiet expiration?
passive
55
how is expiration achieved in quiet expiration?
mainly by elastic recoil of the thoracic cage
56
elastic recoil of the thoracic cage _____ the lungs
compresses
57
in normal lungs, the intrapleural pressure is always _____ in both inhalation and exhalation
negative
58
pneumothorax
presence of air in the pleural cavity
59
describe how a pneumothorax occurs (2)
- thoracic wall is punctured
- inspiration sucks air through the wound into the pleural cavity
60
the potential space a pneumothorax creates causes what?
an air-filled cavity causing the loss of negative intrapleural pressure allowing the lungs to recoil and collapse
61
atelectasis
collapse of part of all of a lung
62
potential causes of atelectasis (4)
- lung tumor
- aneurysm
- swollen lymph node
- aspirated object into airways
63
how does an aspirated object lead to atelectasis?
an airway obstruction causes blood to absorb gases from the alveoli causing a decrease in alveolar volume and subsequent alveolar collapse
64
two factors influence airway resistance
- bronchiole diameter
- pulmonary compliance
65
bronchodilation
increase in diameter of bronchus or bronchiole
66
bronchoconstriction
decrease in diameter of bronchus or bronchiole
67
pulmonary compliance
ease with which the lungs can expand; change in lung volume relative to a given pressure change
68
compliance is reduced by...
degenerative lung diseases in which the lungs are stiffened by scar tissue
69
lung diseases that cause scar tissue (2)
- tuberculosis
- black lung disease
70
compliance of the lungs is limited by...
the surface tension of the water film inside the alveoli
71
what does surfactant do?
disrupts hydrogen bonds between water molecules and thus reduces the surface tension, making them easier to fill with air
72
surfactant is secreted by..
great cells of the alveoli
73
infant respiratory distress syndrome (IRDS)
premature babies lacking surfactant are treated with artificial surfactant until they can make their own
74
what air is available for gas exchange?
the air that enters the alveoli
75
about how much air fills the conducting zone of the airway?
150ml
76
anatomical dead space
the conducting zone of the respiratory system in which no gas exchange occurs
77
the anatomical dead space can be altered somewhat by what?
sympathetic dilation which increases dead space but allows greater flow
78
spirometry
measuring pulmonary ventilation
79
spirometry aids in what?
diagnosis and assessment of restrictive and obstructive lung disorders
80
restrictive disorders include (3)
- black lung disease
- tuberculosis
- any disease that produces pulmonary fibrosis
81
restrictive disorders
reduction in pulmonary compliance, limiting how much lungs can inflate
82
obstructive disorders of the lungs
interfere with airflow by narrowing or blocking the airway making it harder to inhale or exhale a given amount of air
83
obstructive disorders include (2)
- asthma
- chronic bronchitis
84
_____ bombines both elements of both restrictive and obstructive disorders
emphysema
85
eupnea
relaxed, quiet breathing
86
apnea
temporary cessation of breathing
87
dyspnea
labored, gasping breath/shortness of breath
88
hyperpnea
increased rate and depth of breathing in response to exercise, pain, or other conditions
89
hyperventilation
increased pulmonary ventilation in excess of metabolic demand
90
hypoventilation
reduced pulmonary ventilation leading to an increase in blood CO2
91
kussmaul respiration
deep, rapid breathing often induced by acidosis, diabetes-related ketoacidosis
92
air contains
- 78.6% nitrogen
- 20.9% oxygen
- 0.04% carbon dioxide
- 0-4% water vapor
93
air contains minor amounts of...(5)
- argon
- neon
- helium
- methane
- ozone
94
Dalton's Law
total atmospheric pressure in the sum of the contributions of the individual gases
95
partial pressure
the separate contribution of each gas in a mixture
96
composition of inspired and alveolar air differs because of three influences
- air is humidified by contact with mucus membranes
- alveolar air mixes with residual air
- alveolar air exchanges O2 and CO2 with blood
97
air is humidified by contact with mucous membranes
alveolar PH2O is more than 10x higher than inhaled air
98
alveolar air mixed with residual air
oxygen gets diluted and air is enriched with CO2
99
alveolar air exchanges O2 and CO2 with blood (2)
- PO2 of alveolar air is about 65% that of inspired air
- PCO2 is more than 130x higher
100
alveolar gas exchange
the movement of O2 and CO2 across the respiratory membrane
101
for oxygen to get into the blood, it must...
dissolve in the alveolar epithelium (water) and pass through the respiratory membrane separating the air from the bloodstream
102
for carbon dioxide to leave the blood, it must...
pass the other way and then diffuse out of the water film into the alveolar air
103
gases diffuse down their own gradients until...
the partial pressure of each gas in the air is equal to its partial pressure in water
104
what is the first step in alveolar gas exchange?
air in the alveolus is in contact with a film of water covering the alveolar epithelium
105
Henry's Law
at the air-water interface, for a given temperature, the amount of gas that dissolves in the water is determined by its solubility in water and its partial pressure in air
106
the _____ the PO2 in the alveolar air, the ____ O2 the blood picks up
greater, more
107
because the blood arriving at the alveolus has...
a higher PCO2 than air, so it releases the CO2 in the air
108
at the alveolus, the blood is said to
unload CO2 and load O2
109
the unloading of CO2 and loading involves...
erythrocytes
110
efficiency of the alveolar gas exchange depends on...
how long an RBC stays in the alveolar capillaries
111
how long does a RBC need to stay in the alveolar capillaries to reach equilibrium?
0.25 seconds
112
at rest, RBC spend _____ seconds in the alveolar capillaries
0.75
113
in strenuous exercise, RBCs stay for ___ seconds
0.3
114
each gas in a mixture behaves _____
independently, one gas does not influence the diffusion of another
115
variables affecting alveolar gas exchange efficiency (5)
- membrane thickness
- membrane surface area
- solubility of gases
- pressure gradients of the gases
- ventilation-perfusion coupling
116
normally, the PO2 is...
= 104 mmHg in the alveolar air versus 40 mmHg in blood
117
normally, the PCO2 is...
= 46 mmHg in blood arriving versus 40 mmHg in blood arriving versus 40 mmHg in alveolar air
118
how do pressure gradients differ at high altitudes?
partial pressure of all atmospheric gases are lower; pressure gradient for oxygen is lower so less diffuses into blood
119
hyperbaric oxygen therapy
treatment with oxygen at greater than 1 atm of pressure
120
what is hyperbaric oxygen therapy used for? (2)
- gangrene
- carbon monoxide poisoning
121
by the time blood reaches the left atrium, the PO2 is...
95 mmHg
122
why is PO2 95 mmHg by the time it reaches the left atrium?
caused by a mixing of oxygenated blood from the pulmonary vein with deoxygenated blood from the bronchial vein
123
variables affecting alveolar gas exchange efficiency: solubility of gases
equal amounts of O2 and CO2 are exchanged across the respiratory membrane because CO2 is much more soluble and diffuses more rapidly
124
CO2 is _____ time as soluble as O2
20
125
what disease decrease surface area for gas exchange? (3)
- emphysema
- lung cancer
- tuberculosis
126
the respiratory membrane is only _____ thick
0.5um
127
what would happen if the respiratory membrane was thicker?
gases have father to travel between blood and air and cannot equilibrate fast enough to keep up with blood flow
128
what diseases cause thickening of the respiratory membrane? (2)
- pulmonary edema
- pneumonia
129
ventilation-perfusion coupling
gas exchange requires both good ventilation of alveolus and good perfusion of the capillaries
130
pulmonary blood vessels change diameter depending on...
air flow to an area of the lungs
131
bronchi change diameter depending on...
blood flow to an area of the lungs
132
if an area of the lungs is well perfused, what occurs?
bronchodilation
133
gas transport
the process of carrying gases from the alveoli to the systemic tissues and vice versa
134
how much O2 does blood carry?
20ml of O2 per deciliter
135
what molecule is specialized for oxygen transport?
hemoglobin
136
oxyhemoglobin (HbO2)
O2 bound to hemoglobin
136
deoxyhemoglobin (HHb)
hemoglobin with no O2
137
oxyhemoglobin dissociation curve
illustrates relationship between hemoglobin saturation and ambient PO2
138
why does the oxyhemoglobin dissociation curve look the way it does?
occurs because when hemoglobin binds each oxygen, it makes it easier to bind the next one
139
three forms in which carbon dioxide is transported in the body
- carbonic acid
- carbaminohemoglobin
- dissolved gas
140
90% of CO2 is carried as...
carbonic acid (H2CO3)
141
5% of carbon dioxide is carried as either...(2)
dissolved gas or carbaminohemoglobin
142
70% of exchanged CO2 comes from what form of CO2?
carbonic acid
143
23% of exchanged CO2 comes from what form of CO2?
carbaminohemoglobin
144
7% of exchanged CO2 comes from what form of CO2?
dissolved in plasma
145
blood gives up the dissolved CO2 gas and CO2 from _____ more easily than CO2 in _____
carbaminohemoglobin, bicarbonate
146
carbon monoxide (CO)
colorless, odorless gas in cigarette smoke, engine exhaust, and fumes from gas furnaces
147
_____ competes for the O2 binding site on hemoglobin (Hb)
carbon monoxide
148
what is hemoglobin called when carbon monoxide binds to it?
carboxyhemoglobin (HbCO)
149
does CO or O2 bind to hemoglobin more tightly?
CO
150
treatment for CO binding to Hb in smokers (3)
- pure oxygen
- hyperbaric oxygen therapy
- blood transfusion
151
systemic gas exchange
unloading of O2 and loading of CO2 at systemic capillaries
152
carbon dioxide loading (2)
- CO2 diffuses into the blood
- carbonic anhydrase catalyzes the reaction to bicarbonate and hydrogen ions
153
where is carbonic anhydrase found?
red blood cells
154
chloride shift
bicarbonate pumped out of RBC in exchange for a chloride ion from plasma
155
how is the chloride shift performed?
an antiport protein called the chloride-bicarbonate exchanger
156
H+ binding to _____ reduces its affinity for O2
HbO2 (oxyhemoglobin); tends to make hemoglobin release oxygen
157
HbO2 arrives at systemic capillaries _____% saturated and leave _____% saturated
97, 75
158
utilization coefficient
22% of HbO2's load is given up
159
gas exchange reactions that occur in the lungs are _____ of systemic gas exchange
reverse
160
CO2 unloading in the lungs
as Hb loads O2, its affinity for H+ decreases causing it to dissociate from Hb and bind with HCO3-
161
reverse chloride shift
HCO3- diffuses back into RBC in exchange for Cl-, free CO2 that is generated diffuses into alveolus to be exhaled
162
hemoglobin unloads O2 to match....
metabolic needs of different states of activity of the tissues
163
four factors that adjust the rate of O2 unloading to match need
1. ambient PO2
2. temperature
3. ambient pH
4. BPG
164
four factors that adjust the rate of O2 unloading to match need: ambient PO2
active tissues have a low PO2 causing Hb to release O2
165
four factors that adjust the rate of O2 unloading to match need: temperature
active tissues have a higher temperature that promotes Hb to unload O2
166
four factors that adjust the rate of O2 unloading to match need: ambient pH
active tissue pH is higher due to higher concentrations of CO2, lowering blood pH which promotes unloading of O2
167
Bohr effect
describes hemoglobin's lower affinity for oxygen secondary to increases in the partial pressure of carbon dioxide and/or decreased blood pH
168
four factors that adjust the rate of O2 unloading to match need: BPG
RBCs produce a metabolic intermediate of anaerobic metabolism called BPG which binds to Hb, unloading O2 in the process
169
BPG aka
bisphosphoglycerate
170
factors that raise BPG and promote O2 unloading (5)
- raised body temp (fever)
- thyroxine
- growth hormone
- testosterone
- epinephrine
171
describe the effect of temperature on HbO2
as temperature increases, more Hb unloads O2
172
describe the effect of pH on HbO2
as pH lowers, HbO2 releases more O2
