Respiratory Physiology Flashcards
1
Q
What are the Major constituents of the earth’s atmosphere?
A
N2 - 78
02 - 20
2
Q
T or F: 02 is a potent poison that breaks down Carbon skeletons and is used for cellular respiration.
A
True
3
Q
T or F: N2 has an important role in respiration. It is a dilutant gas.
A
False ; n2 doesn’t have a role in respiration
4
Q
High altitude _______(reduces/increases) the inspired pressure of oxygen - not the % of oxygen in the atmosphere!!!!!
A
reduces
5
Q
As altitude increases barometric pressure _______ (increases/decreases)
A
decreases
6
Q
In contrast with air, water can contain varying concentrations of dissolved 02, solubility ____ (rises/falls) as ______ increases.
A
falls; temperature
7
Q
What is the gas exchanger for mammals? ______ What about for fish?______
A
alveolus; secondary lamella
8
Q
What kind of ventilation is present for mammals? ______ What about for fish?______
A
tidal; unidirectional, continuous
9
Q
What kind of 02 content and pressure is present for mammals? ______ What about for fish?______
A
200ml/L
~ 150 mm Hg
.04-9 ml/L (moves alot of water)
1-200 mmHg
10
Q
What % of 02 is utilized for mammals? ______ What about for fish?______
A
25%
80% (more efficient)
11
Q
What is the diffusion rate of C02 and O2 for mammals? ______ What about for fish?______
A
O2 - 500,000 x higher
C02
02 - low
C02 - 23x co2
12
Q
What is the 02 density for fish?
A
1000x air density
13
Q
What is the viscosity of 02 for fish?
A
100x air
14
Q
What is the expired c02 content and pressure present for mammals? ______ What about for fish?______
A
110 ml/L
40-45 mmHg
0-13 ml/L (co2 dissolves)
0-10 mmHg (can get rid of c02 more easily)
15
Q
What is the 02 consumption (rest) for mammals? ______ What about for fish?______
A
200ml/kg/hr (human) higher metabolic rate
50-100 ml/kg/hr (carp)
16
Q
longer fluid = _____(more or less) 02 movement
A
less
17
Q
diffusion is _____ (faster/slower) in h20
A
slower
18
Q
partial pressure difference is defined as : ______
A
diffusion
19
Q
T or f: gas can diffuse through solids
A
true; just slowly
20
Q
Define: a random walk from a region of high
concentration (partial pressure)
to a region of lower partial pressure – gas molecule in gas mixture.
A
diffusion
21
Q
______ IS THE MAIN MECHANISM FOR THE DELIVERY OF OXYGEN TO CELLS.
A
diffusion
22
Q
“DRUNKARD’S WALK” is:
A
MOLECULES MOVE IN THE DIRECTION
OF PRESSURE GRADIENT BUT CHANGE DIRECTION RANDOMLY AS THEY HIT OTHER MOLECULES.
23
Q
EVOLUTION HAS MINIMIZED THE LENGTH OF THE FLUID PATHWAY TO _____ (inhibit/aid ) GAS TRANSPORT
A
aid
24
Q
MOST PROBABLE DISTANCE FROM START IS PREDICTED:
D=L x sqrt( N )(D=DISTANCE,L=STEP LENGTH,N=_______)
A
number of steps
25
• WITH A PATH OF ___ STEPS, THE MOST PROBABLE LOCATION OF A MOLECULE IS 10 STEPS FROM ORIGIN
100
26
AS ORGANISMS GET LARGER THEIR SURFACE AREA (SA) GETS PROPORTIONATELY _______ (larger/smaller) HENCE THE NEED FOR SPECIAL RESPIRATORY ORGANS WITH LARGE SA - gills and lungs
smaller
27
S/A : Volume ratio = ___ : m3
meters squared ; m2
28
Aerobic or Anaerobic respiration?
C6H12O6 ---> 2(CH3COCOOH)+4H 2(CH3CHOHCOOH) + 4ATP
anaerobic
29
Aerobic or Anaerobic respiration?
C6H12O6+6O2=6CO2+6H20+34ATP

aerobic
30
Respiratory Gases are used in which type of respiration? aerobic or anaerobic ?
aerobic
31
Aerobic produces how much ATP from a single glucose? Anaerobic?
34ATP; 4 ATP
32
Vertebrate respiration: Refers to the exchange of O2 and CO2 with the primary gas exchange medium - _____ or air, and transport in a secondary medium which is _____.
water; blood
33
Usually two convective pumps - ______ cavity or _____ wall and heart
buccal cavity; chest wall;
34
Vertebrate respiration: Two diffusion barriers: ____ or ____ gas exchange membrane and ________ fluid at tissue capillaries
gill; lung; interstitial
35
The mechanism of the respiratory pump depends on both the ________ of the vertebrate (fish, amphibian, reptile, bird, mammal) and the primary gas exchange _______ (air or water, or both).
The _________ system design is also determined by these factors
phylogeny; medium; circulatory
36
Cardio-respiratory system is a useful concept – a system that gets oxygen from the ___________ and delivers it to _______
environment; tissues
37
The percentage composition of the atmosphere ______ (does/does not) change with altitude, but barometric pressure _____ (does not/ does). This influences the pressures (partial pressures) of gases in the mixture.
does not; does
38
what is the highest component gas in the atmosphere?
nitrogen gas N2
39
big animals can’t rely on _______ and need ventilated gills or lungs. why?
diffusion; because of their growing surface area to volume ratio.
40
Diffusion - powered by interactions between gas ________. Gases diffuse ____ (up/down) pressure (concentration) gradient of gas molecules.
molecules; dwn
41
Aerobic respiration – uses ___ (a gas), produces ____ (a gas) and H2O
02; c02
42
Low Pressure of 02 = ______ (disease)
hypoxia
43
T or F: ventilation = convection
true
44
2 main pumps in pathway of the respiratory gases :
buccal cavity/chest wall && heart
45
2 main mediums of the pathway of the respiratory gases:
| which is primary and which is secondary?
water/air(primary) && blood (secondary)
46
Pathway of the respiratory gases:
upper and lower airways
Which process is taking place?
convection/ventilation "stirring up"
47
Pathway of the respiratory gases:
Gill or lung (gas exchange area)
Which process is taking place?
diffusion takes place
air/water
buccal cavity/chest wall
48
Pathway of the respiratory gases:
systemic vasculature
Which process is taking place?
convection/ventilation "stirring up"
49
Pathway of the respiratory gases:
interstitial fluid
Which process is taking place?
diffusion
50
in convection in the upper and lower airways:
Whats the medium?
Whats the pump?
water/air
| buccal cavity/ chest wall
51
in convection in the systemic vasculature:
Whats the medium?
Whats the pump?
blood
| heart
52
What is more favorable for gas exchange?
| water or air?
water
53
The Fick equation:
The thicker, the ___ (more/less) diffusion.
less
54
The Fick equation:
____ (gas) is almost insoluble in h20 (this is why we need helmoglobin)
02
55
The Fick equation:
C02 is 20x ___(more/less) soluble than 02.
more
56
The Fick equation:
more area = ____ (more/less) gas diffusion
more
57
The Fick equation:
alveoli walls are ____ (thick/thin)
thin
58
The Fick equation:
D = Sol / sqrt(MW) --> _____ MW means?
MW means molecular weight
59
The Fick equation:
Vgas = A/T * D * (p1 - p2)
p1-p2 ---> define:
T --> define:
A --> define:
pressure gradient
thickness
area
60
What are the 4 vertebrate Gas exchange organs?
| FMBA! (FeMaleBA)
Fish gills
Mammalian lung
Bird lung
Amphibian skin
61
Which of the 4 vertebrate gas exchange organs uses secondary lamellae ?
Whats the method?
fish gills
| counter current
62
Which of the 4 vertebrate gas exchange organs uses parabronchus ?
Whats the method?
bird lung
| cross-current
63
Which of the 4 vertebrate gas exchange organs uses alveolus?
| Whats the method?
mammalian lung
| 'Pool'
64
Which of the 4 vertebrate gas exchange organs uses skin surface?
Whats the method?
amphibian skin
| 'Open'
65
Cutaneous gas exchange represents a(n) _____ model or method. In vertebrates, most important in amphibians with thin, well vascularised, moist, naked skin
does it ever equilibriate?
is it efficient?
open
No
no
66
T or F: In new born humans, cutaneous gas exchange is 5% higher
true
67
in cutaneous gas exchange why does the pressure drop from primary to secondary medium?
the thickness of blood
68
Bullfrog metamorphosis - gas exchangers are skin, skin and gills, skin and lungs!! An model for evolution of air- breathing; however f you can use a ____ you will!
Animals increase surface area of diffusion through ____
lung
| gills
69
Convergent Evolution - Nudibranch mollusc with _____ (internal/external) gills
external
70
Axolotl salamander with ______ (internal/external) gills (neotenous)
external
71
T or F: external gills are very vulnerable and collapse without the support of h20
True
72
Double _______ mechanism in bony and cartilaginous fish
pumping
73
(1)Mouth opens and the jaw is lowered to draw water into the ______ cavity. The __________ then pulls away from the body, expanding the _______ cavity.
buccal cavity; operculum cavity; operculum cavity
74
(2) mouth closes and the lower jaw raises, which squeezes water toward the _______ cavity. Water is forced ___ (in/out) through open operculum.
operculum ______ and the cycle begins again...
opercular cavity; out
| closes
75
When a fish's mouth opens. the water flows in to the Buccal cavity that has a _______ (+/-) pressure and also into the opercular cavity that has a double ______ (+/-) pressure. Operculum is ____. (open/closed)
negative; negative; closed
76
When the fish's mouth closes, the buccal cavity has a double ______ (+/-) pressure and the opercular cavity has a ______ (+/-) pressure. Operculum is ____. (open/closed)
positive; positive; open.
77
Can Fish change the direction of the water flow?
No
78
Ram ventilation: Pelagic fish like some sharks and mackerel (and remora). Mackerel can’t fully oxygenate their blood if prevented from ________.
swimming
79
Note that _____ and _______ flap act as passive flap valves, one open, one closed
mouth; opercular
80
Floor of the mouth acts as a suction pump in phase 1 as it is lowered and as a _____ (positive/negative) pressure pump in phase 2 as it is raised
positive
81
The operculum acts as a suction pump in phase 1, situated behind the curtain of secondary ______,and a positive pressure pump in phase 2, expelling water from the operculum
lamellae
82
T or F: most inspired water passes through the gill curtain for gas exchange
false ; all water
83
T or F: Flow of water is unidirectional, which is energy efficient (in fish gills)
True
84
P1-P2 is _______(constantly changing/constant) along the length of the secondary lamella
constant
85
PO2 of arterial blood is _____(lesser/greater) than PO2 of expired water
greater;
86
Fick equation - basic physics of gas ______. Diffusion of oxygen is driven by the pressure (“concentration”) ______.
exchange; gradient
87
What is an "open" model of vertebrate gas exchange?
through the skin (cutaneous gas exchange) animals can increase surface area by external gills. Invertebrates, most important in tadpoles.
88
In cutaneous gas exchange, animals can increase surface area by ______ _____.
external gills
89
What is the most efficient gas exchange organ and what type of model is it?
PaO2 (oxygen concentration in arterial blood) is ______ (lesser/ greater) than PEO2. (oxygen concentration in expired water).
fish gills
counter-current
greater
90
Amphibian metamorphosis represents a transition from ____, to external gill, to internal gill, to _____ as gas exchange organ.
skin; lung
91
T or F: barheaded Geese can fly over the top of Mt. Everest!
True
92
T or F: mammals and birds evolved from reptiles
true
93
Reptilian lungs exhibit a wide range of complexity, from simple “_______” lungs to relatively complex lungs that are partitioned into many small gas exchange units
unicameral;
94
Complex lungs: many small gas exchange units make a _____ (large/small) SA for gas exchange
large
95
Simple lungs , single gas space “unicameral”, ______ (small/large) SA for gas exchange
small
96
In airbreathers, like reptiles, increased metabolic rate (active lifestyle) is associated with an ______ (decrease/increase) in surface area of lung for gas exchange
increase
97
Parabronchi refers to birds with ___ (uni/bi)-directional ventilation.
more SA for active metabolism
unidirectional
98
Alveoli refers to mammals, with ___ ventilation
| more SA for active metabolism
tidal
99
In birds: the air sacks are connected to hollow ____.
bones
100
in an ostrich, the lungs are _____.(basal/dorsal)
dorsal
101
If an air sac has high c02 levels and low 02, it must get air that has already moved through the ____. This is the _____ sac.
lungs; anterior
102
If an air sac has low C02 levels and 21% 02, the air must have reached the sac before passing through the ____. This is the _____ sacs.
lungs; posterior
103
Air must move directly to the ________ sacs, then through the lungs, and then to the _______ sacs.
posterior sacs, anterior sacs.
104
Gas flow through the mesobronchus is ____, but flow along the parabronchi is _________ on both inspiration and expiration!!!!!!
tidal ; unidirectional
105
Mesobronchus takes air to the _____ sacs.
| This is ____ gas flow.
posterior; tidal
106
Parabronchus takes air to the lungs and the _____ sacs. This is ______ flow.
anterior; unidirectional
107
First Inhalation: 'a' sac _______ ;'p' sac _______.(expands/contracts)
expands ; expands
108
First Exhalation: 'a' sac _______ ;'p' sac _______.(expands/contracts)
contracts ; contracts
109
How many breathes does it take to pass a full cycle of 02 through both sacs?
2 breaths
110
T or F: birds use valves to maintain pressure within anterior and posterior sacs.
False; no valves used; Fluidonic valving.
111
"Fluidonic" valving - no physical valves . Depends on ______ of 90º exits.
diameter
112
Section of a _______– gas flow is unidirectional
parabronchus
113
If Blood flow is ________ , its at 90 degrees to air flow
cross current
114
Gas flow through parabronchi is _________, not ___, as in amphibian, reptile and mammal lung
unidirectional; tidal
115
Whats the advantage of the cross current system?
no unventilated "dead space" or residual volume
116
Result of this cross – current arrangement – the PO2 of arterial blood is _____ (higher/lower) than the PO2 in exhaled gas!!!
higher
117
What is the formula for Boyle's Law?
P1 x V1 = P2 x V2
118
Boyle's law. An increase of volume will _____ pressure.
decrease
119
Boyle's law. A decrease of volume will ______ pressure.
increase
120
The intercostal muscles ______ (contract/relax) during inhalation to increase chest volume.
contract
121
The diaphragm ____ (raises/lowers) during inhalation to increase chest volume.
lowers
122
Air flows in during inhalation because of _____ law.
Boyles
123
Inhalation vs Exhalation:
Which requires muscle work?
Inhalation
124
Vertebrate lungs have become progressively subdivided to increase the ____ for gas exchange.
Surface area
125
Birds -Tidal gas flow in ________ is converted to unidirectional flow in_________.
mesobronchus; parabronchi
126
Blood flow at 90 degrees to gas flow is an efficient ___________ system - pressure (concentration) of oxygen in arterial blood is ______ (higher/lower) than that in expired gas
cross-current; higher
127
In mammals the ______ are ventilated tidally
alveoli
128
T of F: in expiration alveoli full deflate and eventually fully inflate on inspiration.
false; partially deflate on exhalation.
129
Inspired air containing 21% O2 at 150 mm Hg is diluted by about 3 litres of ______ alveolar gas with ____ (more/less) O2.
residual; less
130
Normal alveolar pressures are determined by _____ blood and inspired gas being brought to alveolar units in a __:__ ratio
resulting typically in PAO2 = ___ mm Hg; PACO2 = ___ mm Hg.
venous, 1:1
100; 40
131
In the mammalian lung the pressure of oxygen in arterial blood can never _____ (equal/exceed) the pressure in expired gas.
exceed
132
This “pool” system is _____ (less/more) effective at exchanging gases than either countercurrent or crosscurrent systems
less
133
In mammals, inspiration is by an aspiration or _____ mechanism
thoracic volume ______ (increase/decrease) and pressure at alveoli falls below atmospheric
air flows in (Boyle’s law). Main inspiratory muscle is the _______.
suction
increases
diaphragm
134
Tidal volume = ____ ml
500ml
135
Atomic Dead space = ____ ml
150 ml
136
Alveolar gas = _____ ml
3L
137
Pulmonary capillary blood = __ ml
70ml
138
Total Ventilation = _____ ml/min
7500 ml/min
139
Frequency (at rest) = ___ /min
15 / min
140
Alveolar ventilation = ____ml/min
5250ml/min
141
Pulmonary blood flow = ___ ml/min
5000 ml/min
142
Most oxygen is transported reversibly combined with _______
hemoglobin (Hb)
143
Most carbon dioxide is transported as ______ ion in the plasma
bicarbonate ion
144
In Pulmonary artery(mixed venous blood): partial pressure of :
P-O2 = __ mmHg
P-CO2 = __ mmHg
40mmHg
| 46 mmHg
145
In alveolus: partial pressure of :
P-O2 = __ mmHg
P-CO2 = __ mmHg
100 mmHg
| 40 mmHg
146
In Pulmonary vein (arterial blood) : partial pressure of :
P-O2 = __ mmHg
P-CO2 = __ mmHg
100 mmHg
| 40 mmHg
147
Pulmonary vein consists of what type of blood? (arterial or mixed venous blood)
arterial blood
148
Pulmonary artery consists of what type of blood? (arterial or mixed venous blood)
mixed venous blood
149
Atmospheric air at airway opening : partial pressure of :
P-O2 = __ mmHg
P-CO2 = __ mmHg
150mmHg
| 0 mmHg
150
Oxygen is very ______(insoluble/soluble) in plasma water.
insoluble
151
you need a carrier protein, (_____), that can transport lots of O2 at arterial PO2, and release it to the tissues at _____ PO2’s
hemoglobin Hb; venous
152
1 g of Hb combines with ___ ml O2
1.39 ml O2
153
Typical human blod contains ____ g Hb/100ml
15g
154
Therefore at arterial PO2, the blood can transport : _____ ml O2/100ml
21.15ml 02/100ml
155
A hemoglobin protein has ___ subunits
four
156
Each subunit of hemoglobin contains an ___ ___ core to which an 02 molecule ____.
Fe++ ion; binds
157
Is hemoglobin oxidized during binding?
No
158
T or F: arteriole blood is an important O2 store.
False; venus blood.
159
Typically, PO2 in tissue capillaries will ____ (increase/decrease) during strenuous exercise.
decrease (20mmHg)
160
@ p50 --> ___ of every 4 Fe++ ions have bound 02.
2 or 50%
161
Typical PO2 in tissue capillaries ____(increase/ decrease) at rest.
increase ~40mmHg
162
T or F: @ PO2 of 100 mmHg nearly all Fe++ are bound to O2
True. nearly
163
Low oxygen hemoglobin is represented by the letter __
T
164
high oxygen hemoglobin is represented by the letter __
R
165
High Oxygen vs Low oxygen Hemoglobin:
Which is rotated 15º?
high oxygen
166
Hemoglobin :
The Fe++ are located in what type of pocket?
Hydrophobic pocket;
167
hemoglobin :
The Fe++ are located on what type of ring?
Porphyrin ring
168
Salt bridge bonds are located on hemoglobin subunits between what 2 elements?
N+ and O-
169
Salt bridge bonds are broken on Hemoglobin sub units due to what?
binding Oxygen
170
On Myoglobin, what amino acid resides in hydrophobic pockets?
Tyrosine
171
T or F: H+ strengthen salt bridge bonds.
True
172
As you work out, your lactic acid builds up and increases H+ concentration. As a result Will the P50 shift left or right? Will salt bridge bonds be strengthened or broken? What will happen to the C02 concentration? This will overall increase or reduce Hemoglobin's affinity?
shift right
strengthened.
CO2 will increase
reduce affinity
173
Anemia _____ (increases/reduces) the blood oxygen concentration by reducing carrying capacity .
reduces
174
CO poisoning is a form of functional ____.
anemia
175
Anemia and CO poisoning both ______ (increase/decrease) the affinity of O2 in hemoglobin and reduces the amount of available oxygen.
increase ;
176
Carbondioxide transport by the blood:
CO2 is dissolved in ____ Water - about __ %
plasma; 5%
177
CARBAMINO COMPOUNDS WITH Hb – ABOUT __%
5%
178
AS BICARBONATE IN PLASMA – ABOUT___%
90%
179
Most bicarbonate is transported in plasma after being rapidly formed in RBC’s with the aid of_________ enzyme
carbonic anhydrase
180
V-a difference concentrations:
cabamino = ___%
HCO3- = _____ %
C02 = _____ %
21%
69%
10%
181
CO2 Combines with H20 to form --> _____ + H+ with the help of what enzyme?
Where does this proces take place?
HCO3-
carbonate anhydrase
RBC
182
_____ is a carrier protein in vertebrate red blood
| cells (rbc) that can combine reversibly with O2 depending on the ____.
hemoglobin ; P02
183
As O2 loads, Hb molecules change from a ____ (tense/relaxed) to a ______ (tense/relaxed) state as bonds between four globin subunits break down
What are these bonds called?
tense ; relaxed
| salt bridge bonds N -- 0
184
Active sites are ___ ions in planar rings contained in a ______ pocket in globin molecules. Therefore one Hb molecule can load ___ molecules of O2
Fe++; Hydrophobic ; four
185
____ g of Hb combines with 1 ml O2. Usually about ____ g Hb/100 ml human blood giving ___ ml O2/100ml blood
1. 39g; 15g; 20.85ml O2/100ml
186
Dissociation curve is ____ (S-shaped) with a P50 of __ mm Hg
sigmoid; 27 mmHg
187
Reduced affinity = ____ shift at P50. Produced by CO2 and H+ which strengthen bonds and promote a tense state - Therefore, O2 unloads at tissues, where CO2 is high
right shift;
188
CO2 is largely transported as _____ in plasma although most is produced in ___ with the aid of _______ enzyme
HCO3- ; RBC'S; carbonic anhydrase
189
What are the 3 main factors that increase the respiratory rate?
Conscious effort
Large decrease in blood levels of O2
an increase in blood levels of CO2 or H+ (exercise)
190
Factors that inhibit respiratory rate:
stretching of the lungs during inhalation
Conscious effort (Holding breath)
sleep
191
What is a clinical case that illustrates respiratory control by metabolic and behavioural systems?
```
1. "locked in" syndrome
"the diving bell and the butterfly"
2. Ondine's curse
have to consciously think about breathing
dont cheat on german water nymphs
```
192
Locked in syndrom can occur from ______ stroke (or _____).
______ (able/unable) to move voluntarily (eg. eyes)
regular breathing pattern driven by '_______ system'
brainstem; pons;
unable
metabolic
193
Ondine's curse: patient with tumour at back of ______ .
unable to sleep because he stopped breathing if he does so.
_______ (regular/irregular) breathing when alert and its driven by ' ________ system '
medulla
irregular
behavioural
194
Metabolic (chemoreceptor) control of breathing:
Central Controller : includes the ____, medulla, and other parts of the brain.
Receives input from ______.
Gives output to the ______.
Pons
sensors
effectors
195
Metabolic (chemoreceptor) control of breathing:
Sensors : includes __________, lung, and other receptors.
Receives input from ______.
Gives output to the ______.
chemorecepotors
surroundings and effectors
central controller
196
Metabolic (chemoreceptor) control of breathing:
Effectors : includes the _______ muscles.
Receives input from ______.
Gives output to the ______.
respiratory msucles;
central controller
sensors
197
Perifpheral chemoreceptors include : the ______ and _____ bodies.
carotid; aortic
198
Carotid body chemorecepotrs have a circular type I cell. and a type II cell (_____ cell). Connected to the type __ cell is a single ____ afferent.
glial
type I
CSN - carotid sinus nerve
199
The sensors in the cartotid body are the ______ cells.
type I
200
carotid sinus nerve connects to which cell? type I or type II?
type I
201
As arterial O2 ____ (rises/falls), there is a increased frequency of nerve firing.
falls
202
Ventilatory responses to oxygen:
Relationship approximates a ______ (triangular/rectangular) hyperbola.
Responses ______ (constant/ vary) between individuals.
Relatively _____ (weak/strong) responses to 02 compared to CO2 response.
Modulated by P___2 (O2/ CO2)
rectangular
highly variable
weak
PCO2
203
____ are the only significant source of hypoxic ventilatory drive.
carotid bodies
204
Central chemoreceptors are located in the _____ ______ in cerebral spinal fluid.
medulla oblongata
205
Ventilatory responses to Carbon dioxide:
Ventilatory response to CO2 is close to a _______(parabolic/ straight line) relationship.
The slope is very _______ (constant/variable) between individuals
Dog leg (hockey stick) effect : present in _____ (sleeping/awake) humans. Anaesthetized animals will stop breathing if ____ falls below a threshold.
Measurements ____ (easy/difficult) to attain because ventilation varies over a wide range and you have to hold P___ (O2/CO2) constant.
Modulation by P___ (O2/CO2)
```
straight line
variable
Awake; C02
difficult; O2
O2
```
206
___% of drive to breathe is from chemoreceptors.
80% or most
207
Central chemoreceptor cells respond to ________ (increased/decreased) CO2 in arterial blood to increase breathing.
increased
208
There are no protein _____ in the Cerebral spinal fluid
buffers
209
Breathing, uniquely, is under both ______ and _______ control
metabolic and behavioral
210
Cells in the _____ that generate respiratory “drive” receive input from receptors in the lungs, brain and _____ and also the cortex.
medulla; arteries
211
Peripheral (carotid and _____) chemoreceptors monitor O2 (and secondarily CO2) in arterial blood going to the ____.
aortic; brain
212
Peripheral chemoreceptors evolved from ____ _____ receptors in ancestoral fish. Carotid body provides ____ (most/all/some) of the ventilatory sensitivity to hypoxia and about ___% of the CO2 sensitivity in mammals
gill arch receptors; all ; 15%
213
Sensitivity to ______ is valuable at high altitude where PO2 is reduced
hypoxia
214
Central chemoreceptors in the medulla are only sensitive to ______and provide about 85% of the CO2 drive.
Fish have central chemoreceptors sensitive to CO2, but there is a small signal for them to detect as CO2 is lost at the _____ because it highly _____ (soluble/insoluble) in water
CO2;
| gills; soluble
215
CO2 normally provides the most powerful _________ (type of) drive to breath in mammals - small increases above the normal arterial PCO2 (about 40 mmHg) cause _____ increases in ventilation to drive off excess CO2
metabolic; large
