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Biology 2312 > Chapter 48 > Flashcards

Chapter 48 Flashcards

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1
Q

What is the major physiological challenge facing all multicellular animals?

A

obtaining sufficient O2 and getting rid of excess CO2

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2
Q

Which animal is the respiratory champion?

A

elephant seals, which can hold their breath for over 2 hours

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3
Q

Invertebrates display a wide variety of respiratory organs, including

A

the epithelium; tracheae; gills

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4
Q

Which vertebrates use gills?

A

fish; larval amphibians

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5
Q

What do adult amphibians use to respire?

A

skin; other epithelia (either supplementary or primary external respiratory organ)

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6
Q

Generally speaking, which animals have lungs?

A

adult amphibians; reptiles; birds; mammals

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7
Q

(T/F) Lungs are only present in terrestrial animals.

A

False, lungs are also present in aquatic animals

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8
Q

What is necessary for plasma membranes to be stable?

A

Plasma membranes must be surrounded by water to be stable

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9
Q

The external environment in gas exchange is always

A

aqueous (even in terrestrial animals, since a fluid lines the respiratory organs)

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10
Q

What drives the diffusion of gas into the fluid layer surrounding respiratory organs in vertebrates?

A

passive diffusion - concentration difference between O2 and CO2

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11
Q

For dissolved gases, concentration is usually expressed in

A

partial pressure

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12
Q

What law governs the relationship of the rate of diffusion between two regions?

A

Fick’s Law of Diffusion

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13
Q

What does Fick’s Law of Diffusion say?

A

the rate of diffusion (R) is directly proportional to the pressure difference (Δp) between the two sides of the membrane and the area (A) over which the diffusion occurs

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14
Q

What is the relationship between R and d in Fick’s Law?

A

R is inversely proportional to the distance (d)

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15
Q

Write out Fick’s Law.

A

write out pg. 1002

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16
Q

How can R in Fick’s Law be optimized?

A

increase area; decrease distance; increase concentration difference

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17
Q

What is the maximum diffusion distance for the levels of oxygen needed by cellular respiration?

A

0.5 mm

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18
Q

What are the consequences for the maximum diffusion distance of O2 at 0.5 mm?

A

bacteria are small enough, but multicellular animals require structural adaptations to enhance gas exchange

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19
Q

Do invertebrates have specialized respiratory organs?

A

No, they lack specialized respiratory organs

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20
Q

How do invertebrates increase the oxygen concentration difference?

A

some create a water current that continuously replaces the water over respiratory surfaces

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21
Q

Which invertebrates possess respiratory organs?

A

mollusks; arthropods; echinoderms

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22
Q

Give two ways in which respiratory organs maximize Fick’s law.

A

bring the external environment closer to the internal fluid to minimize distance; maximizes surface area

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23
Q

Which factor is affected by continuously beating cilia?

A

concentration difference (because beating cilia continuously replenishes water/O2)

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24
Q

What are gills?

A

specialized extensions of tissue that project into water

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25
Q

What is the simplest form of gills?

A

papillae of echinoderms

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26
Q

What is the most complex form of gills?

A

highly convoluted gills of fish

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27
Q

What is the primary advantage of gills in terms of respiration?

A

enables aquatic organisms to extract far more oxygen from water than would be possible from just body surface

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28
Q

External gills are found in what organisms?

A

fish; amphibian larvae

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29
Q

Give examples of organisms with external gills.

A

larvae of many fish/amphibians; axolotl (amphibian)

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30
Q

What is unusual about the axolotl?

A

retains larval features throughout its life

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31
Q

What are the disadvantages of external gills?

A

must be constantly moved to ensure contact w/ fresh water w/ high O2; significant resistance to movement; easily damaged

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32
Q

What are branchial chambers?

A

structures that provide a means of pumping water past stationary gills

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33
Q

What is the composition of air?

A

21% oxygen; 78% nitrogen; <1% CO2 + other gases

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34
Q

Describe the nature of nitrogen gas in air.

A

inert; not part of respiratory processes

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35
Q

What is atmospheric pressure?

A

pressure exerted by the atmosphere on the body surfaces of animals

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36
Q

What is 1 kPa in mm Hg?

A

1 kPa = 7.5 mm Hg

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37
Q

What is sea level in terms of mm Hg?

A

760 mm Hg

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38
Q

(T/F) Atmospheric percentiles change as altitude changes.

A

False, atmospheric percentiles do NOT change with changing altitudes.

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39
Q

Compare the rate of oxygen diffusion into blood at higher and lower elevations.

A

At higher elevations, rate is lower; at lower elevations, rate is higher

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40
Q

Are most gases able to dissolve in water?

A

No, most gases dissolve poorly in water

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41
Q

What are three factors that increase the solubility of gases in water?

A

higher pressure; cold water; lack of other solutes

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42
Q

(T/F) The respiratory system is independent of the vascular system.

A

True, the respiratory system is independent of the vascular system.

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43
Q

What is the minimum number of cell layers for entering the bloodstream?

A

2

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44
Q

What is the branchial chamber in mollusks?

A

mantle cavity

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45
Q

Describe the structure of the mantle cavity.

A

opens to the outside; contains the gills

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46
Q

How does the mantle cavity function as a branchial chamber?

A

contraction of the muscular wall of the mantle cavity draws in water through inhalant siphon and expels through exhalant siphon

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47
Q

Where is the branchial chamber located in crustaceans?

A

between the bulk of the body and the hard exoskeleton of the animal

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48
Q

Describe the structure of the branchial chamber in crustaceans.

A

opens to the surface beneath a limb; contains gills

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49
Q

How does the branchial chamber in crustaceans function?

A

movement of limb draws water through branchial chambers which creates current over gills

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50
Q

Branchial chambers are found in which types of organisms?

A

mollusks; crustaceans

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51
Q

Where are the gills of bony fishes located?

A

between oral cavity and opercular cavity

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52
Q

What is another name for the oral cavity found in bony fishes?

A

buccal (mouth) cavity

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53
Q

What purpose do the buccal and opercular cavities serve in respiration in bony fishes?

A

they are pumps that expand alternately to move water into mouth, through gills, and out of body via open opercula

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54
Q

Which fish have immobile opercula and why?

A

tuna, because they swim continuously

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55
Q

How do fish with immobile opercula breathe?

A

swim with mouths partly open, which constantly forces water over gills

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56
Q

What is ram ventilation?

A

bony fishes with immobile opercula swim with mouths partly open, which constantly forces water over gills

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57
Q

What is the remora?

A

bony fish that rides piggyback on sharks

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58
Q

How does the remora breathe?

A

when hitched to a shark, uses ram ventilation; uses normal pumping action when shark stops swimming

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59
Q

How many gill arches can be found on each side of the fish’s head?

A

between 3 and 7 gill arches

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60
Q

Each gill arch is composed of

A

two rows of gill filaments

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61
Q

Each gill filament is composed of

A

lamellae, which project out into the flow of water

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62
Q

How do blood and water flow with respect to lamellae?

A

Blood flows in the opposite direction of water flow

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63
Q

What is countercurrent exchange?

A

blood and water flow in opposite directions in lamellae to maximize oxygenation

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64
Q

How does countercurrent exchange maximize oxygenation in terms of Fick’s law?

A

it maintains a positive oxygen gradient along the entire pathway for diffusion, which increases Δp in Fick’s law

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65
Q

If blood and water flowed in the same direction, it would be called

A

concurrent flow

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66
Q

Why isn’t concurrent flow a good idea?

A

because the concentration difference would decrease and there would eventually be no further net diffusion

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67
Q

What is the most efficient respiratory organ?

A

gills, because of countercurrent exchange

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68
Q

What is cutaneous respiration?

A

process of exchanging oxygen and CO2 across skin

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69
Q

Describe cutaneous respiration in amphibians.

A

supplements (sometimes replaces) action of the lungs

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70
Q

Can animals respire exclusively through cutaneous respiration?

A

Yes, some terrestrial amphibians such as plethodontid salamanders use cutaneous respiration exclusively

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71
Q

Which animals use cutaneous respiration?

A

amphibians; reptiles (like turtles)

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72
Q

Why do terrestrial reptiles have dry/tough skin?

A

to prevent desiccation and to prevent cutaneous respiration

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73
Q

What are tracheae?

A

small, branched cuticle-lined air ducts

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74
Q

Where are tracheae found?

A

terrestrial arthropods

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75
Q

Tracheae branch into

A

tracheoles

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76
Q

What are tracheoles?

A

series of tubes that transmit gases throughout the body

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77
Q

In arthropods, how is oxygen delivered to cells?

A

tracheoles are in direct contact with individual cells so that oxygen can diffuse directly across plasma membranes

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78
Q

How does air enter the tracheae of arthropods?

A

passes through specialized openings of the exoskeleton called spiracles

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79
Q

What are spiracles?

A

specialized openings of the exoskeleton through which air passes

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80
Q

How are spiracles opened and closed?

A

valves

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81
Q

What was the major evolutionary mechanism that allowed arthropods to invade land?

A

prevention of water loss by closing spiracles

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82
Q

Why were gills replaced with lungs in terrestrial animals?

A

air is less supportive than water; water evaporates

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83
Q

Elaborate on “air is less supportive than water.”

A

gills lack structural strength and rely on water for support; if a fish were to live out of water, they would have plenty of O2 but would suffocate since the gills would collapse

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84
Q

(T/F) Air is usually saturated with water.

A

False, air is rarely saturated with water vapor (except after a rainstorm).

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85
Q

Elaborate on “water evaporates.”

A

Gills would provide an enormous surface area for water loss.

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86
Q

How does the lung minimize water evaporation?

A

moves air through a branched tubular passage

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87
Q

Describe the directionality of air flow in lungs.

A

two-way flow in the same airway passage

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88
Q

What natural phenomenon allows for the constancy of atmospheric composition of gases?

A

convection currents

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89
Q

What is a barometer?

A

apparatus that measures air pressure

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90
Q

What is the maximum altitude for human survival?

A

6000 m

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91
Q

Describe the appearance of lungs in amphibians.

A

saclike outpourings of the gut

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92
Q

Compare the surface area available in the lungs of amphibians to the surface area available in the lungs of other terrestrial vertebrates.

A

less surface area in amphibian lungs than in other terrestrial vertebrate lungs

93
Q

The opening to each amphibian lung is controlled by

A

a valve called the glottis

94
Q

Which mechanism do amphibians use to breathe?

A

positive pressure breathing

95
Q

What is positive pressure breathing (in amphibians)?

A

they fill oral cavity with air and elevate floor of oval cavity, which pushes air into the lungs

96
Q

Give an analogy for positive pressure breathing in humans.

A

forcing air into a person’s lung by performing mouth-to-mouth resuscitation

97
Q

Which mechanism do most reptiles use to breathe?

A

negative pressure breathing

98
Q

What is negative pressure breathing?

A

they expand rib cages by muscular contraction which creates lower pressure inside lungs, which pushes air into lungs

99
Q

What are alveoli?

A

tiny grape-like sacs that provide more surface area for gas exchange

100
Q

How thick is the epithelium of an alveolus?

A

one cell thick

101
Q

How thick are the blood capillaries surrounding alveoli?

A

one cell thick

102
Q

What is the distance for gas diffusion in bird/mammalian alveoli?

A

0.5 to 1.5 micrometers (very small)

103
Q

Describe the passage of air in the mammalian respiratory system.

A

air is inhaled through mouth/nose past pharynx into larynx; then passes through glottis; then passes into tracheae; passes into left or right bronchus; passes into bronchioles; passes into alveoli

104
Q

The mammalian tracheae is divided into

A

right and left bronchi

105
Q

In human lungs, how many alveoli are there?

A

each lung contains about 300 million alveoli

106
Q

What is the total surface area available for diffusion in the human lung?

A

80 m^2 (42x surface area of body)

107
Q

Which animal has the most efficient respiratory system among terrestrial vertebrates?

A

avians

108
Q

Where does gas exchange occur in the avian respiratory system?

A

air is channeled through tiny vessels called parabronchi, where gas exchange occurs

109
Q

Describe the directionality of air flow in avians.

A

air flow in parabronchi is one-directional; old air exits lungs by different route

110
Q

In other terrestrial vertebrates, the two-directional flow of air results in

A

inhaled fresh air mixing with old, oxygen-depleted air

111
Q

What two unique structures in birds help with unidirectional air flow?

A

the anterior and posterior air sacs

112
Q

How is unidirectional air flow accomplished in birds?

A

both anterior and posterior sacs expand upon inflation but only posterior sac is filled w/ new air; anterior sac fills with old air pulled from lungs; upon exhalation old air in anterior sac is pushed out of body and new air in posterior sac enters lungs

113
Q

How many cycles of respiration are there in birds?

A

two cycles, but the air inhaled in the first cycle isn’t exhaled until the second cycle

114
Q

Draw out the two cycles of respiration in birds.

A

draw page 1009, Figure 48.9

115
Q

In what ways does the unidirectional air flow in birds permit further respiratory efficiency?

A

crosscurrent blood flow has greater capacity to extract oxygen from air

116
Q

What is crosscurrent blood flow in birds?

A

flow of blood through avian lung runs at 90 degree angle to air flow

117
Q

In terms of everyday life, why do birds need a much more efficient respiratory system?

A

because they often fly at really high altitudes, where less oxygen is available

118
Q

How many capillaries can be found in each lung?

A

about 30 billion (100 capillaries per alveolus)

119
Q

Blood returning from systemic circulation has a PO2 of

A

40 mmHg

120
Q

The PO2 in alveoli is

A

105 mm Hg

121
Q

Blood leaving the lungs has a PO2 of

A

100 mHg

122
Q

If the PO2 in alveoli is 105 mmHg and blood leaving the lungs has a PO2 of 100 mmHg, what does this mean?

A

the lungs do a very efficient - but not perfect - job of oxygenating blood

123
Q

What thin membrane covers the outside of each lung?

A

visceral pleural membrane

124
Q

What is the visceral pleural membrane?

A

thin membrane that covers the outside of each lung

125
Q

What membrane covers the inner wall of the thoracic cavity?

A

parietal pleural membrane

126
Q

What is the parietal pleural membrane?

A

lines the inner wall of the thoracic cavity

127
Q

What is the pleural cavity?

A

the space between the visceral pleural membrane and the parietal pleural membrane; small and filled with fluid

128
Q

What is the purpose of the fluid in the pleural cavity?

A

causes the parietal pleural membrane to stick to the visceral pleural membrane, which couples the lungs to the thoracic cavity

129
Q

Describe why the two lungs aren’t packaged together.

A

The pleural membranes package each lung separately so that if one lung collapses, the other lung can still function

130
Q

During mammalian inhalation, how is thoracic volume increased?

A

through contraction of two sets of muscles: external intercostal muscles and the diaphragm

131
Q

Contraction of the external intercostal muscles results in

A

raising of the ribs and expansion of the rib cage

132
Q

Contraction of the diaphragm results in

A

the diaphragm lowering and assuming a more flattened shape

133
Q

What is the diaphragm?

A

convex sheet of striated muscle separating the thoracic cavity from the abdominal cavity

134
Q

What kind of breathing mechanism do mammals/humans employ?

A

negative pressure ventilation

135
Q

Expansion of the thoracic volume places the thorax and lungs under what tension?

A

elastic tension

136
Q

Why do humans have unforced exhalation?

A

because the relaxation of the external intercostal muscles/diaphragm releases the elastic tension which allows the thorax and lungs to recoil

137
Q

What muscles are used to force inhalation in humans?

A

accessory respiratory muscles like the sternocleidomastoid

138
Q

Each breath in a human moves how much air into and out of the lungs?

A

tidal volume of 500 mL of air moves into and out of the lungs

139
Q

What is anatomical dead space?

A

tubular passages (trachea, bronchi, bronchioles) where no gas exchange occurs

140
Q

How much tidal volume is contained in the anatomical dead space?

A

150 mL of tidal volume is in the anatomical dead space

141
Q

What is the vital capacity?

A

maximum amount of air that can be expired after a forceful, maximum inhalation

142
Q

What is the vital capacity in young men?

A

4.6 L

143
Q

What is the vital capacity in young women?

A

3.1 L

144
Q

Why is the vital capacity clinically important?

A

abnormally low vital capacity can indicate damage to alveoli

145
Q

What is hypoventilation?

A

insufficient breathing to maintain normal blood gas measurements

146
Q

What is the best indicator of hypoventilation?

A

rise in blood PCO2

147
Q

What is hyperventilation?

A

excessive breathing

148
Q

What is the best indicator of hyperventilation?

A

abnormally low blood PCO2

149
Q

Why is increased breathing during exertion not considered hyperventilation?

A

because the faster/more forceful breathing is matched to the higher metabolic rate, so blood gas measurements are still normal

150
Q

Ventilation, generally speaking, is controlled by

A

the nervous system

151
Q

Each breath is initiated by

A

neurons in the respiratory control center

152
Q

Where is the respiratory control center located?

A

medulla oblongata

153
Q

What stimulates the external intercostal muscles/diaphragm to contract?

A

neurons in the respiratory control center

154
Q

What causes the external intercostal muscles/diaphragm to relax?

A

neurons in the respiratory control center stop producing impulses

155
Q

What kind of muscle is used for breathing muscles?

A

skeletal BUT they are usually controlled automatically; can be voluntarily overridden

156
Q

What is the primary initiator for the urge to breathe?

A

rise in PCO2 rather than a fall in PO2

157
Q

A rise in PCO2 results in

A

increased production of H2CO3

158
Q

What effect does H2CO3 have on blood pH?

A

H2CO3 lowers blood pH (more acidic)

159
Q

A fall in blood pH results in

A

stimulation of chemosensitive neurons in the aortic and carotid bodies

160
Q

Where are the aortic and carotid bodies located?

A

aorta and carotid artery, respectively

161
Q

When stimulated, what do the aortic/carotid bodies do?

A

send impulses to the respiratory control center, which stimulates increased breathing

162
Q

What other mechanism, other than aortic and carotid bodies, exists to stimulate breathing when blood pH is too low?

A

brain contains central chemoreceptors that are stimulated by a drop in the pH of cerebrospinal fluid (CSF)

163
Q

Why can’t a person voluntarily hyperventilate for too long?

A

because the decreases in PCO2 and increase in blood pH suppresses the reflex drive to breathe

164
Q

Why does deliberate hyperventilation allow people to hold their breath longer?

A

because CO2 levels are lowered, which takes longer to build back up and postpones the need to breathe

165
Q

For people with normal longs, when does PO2 become a primary initiator?

A

at high altitudes where PO2 is low

166
Q

What does COPD stand for?

A

chronic obstructive pulmonary disease (COPD)

167
Q

What are COPDs?

A

any disorder that obstructs air flow on a long-term basis

168
Q

List the major COPDs.

A

asthma; chronic bronchitis; emphysema

169
Q

What happens in asthma?

A

allergen triggers release of histamine or other inflammatory chemicals which can cause constriction of bronchi or suffocation

170
Q

What happens in emphysema?

A

alveolar walls break down and the lung exhibits larger but fewer alveoli; lungs become fibrotic and less elastic; air passages open adequately but collapse and obstruct outflow of air

171
Q

What is the primary cause of emphysema?

A

cigarette smoking

172
Q

Which cancer accounts for more deaths than any other cancer?

A

lung cancer

173
Q

Is lung cancer a COPD?

A

no, it usually follows or accompanies a COPD

174
Q

What is the most important cause of lung cancer?

A

cigarette smoking

175
Q

What is the second-most important cause of lung cancer?

A

air pollution

176
Q

Where do most lung tumors originate?

A

mucous membranes of large bronchi

177
Q

How do lung tumors affect breathing?

A

as the tumor invades the bronchial wall and grows around it, it compresses airway and may cause collapse of distal parts of the lung

178
Q

Why is lung cancer in smokers rarely noticed?

A

because lung cancer causes coughing but smokers cough anyways, so they don’t really notice

179
Q

What percentage of patients with lung cancer survive after 5 years of diagnosis?

A

3%, because lung cancer metastasizes very quickly

180
Q

Protruding papulae are found in which organisms?

A

echinoderms

181
Q

What is the atmospheric PO2?

A

160 mm Hg

182
Q

Which is more tolerable, alkalinity or acidity?

A

alkalinity

183
Q

Emphysema affects what factor of Fick’s Law?

A

surface area

184
Q

(T/F) There are nerve endings in our lungs.

A

False, we don’t have nerve endings in our lungs

185
Q

In physiological conditions, how much O2 can blood plasma contain, per liter?

A

3 mL O2 per liter blood plasma

186
Q

In physiological conditions, how much O2 can whole blood contain, per liter?

A

200 mL O2 per liter whole blood

187
Q

Hemoglobin is composed of

A

four polypeptide chains

188
Q

Oxygen-bound hemoglobin is called

A

oxyhemoglobin

189
Q

Where does hemoglobin load up with oxygen?

A

alveolar capillaries of the pulmonary circulation

190
Q

Oxygen-bound hemoglobin that releases oxygen is called

A

deoxyhemoglobin

191
Q

What is the color of deoxyhemoglobin?

A

darker red, but gives a bluish tinge to tissues

192
Q

(T/F) Hemoglobin is exclusively used in vertebrates.

A

False. Used in all vertebrates, but is also used in many invertebrates like annelids, mollusks, echinoderms, flatworms, some protists.

193
Q

What is the oxygen carrier in non-hemoglobin invertebrates?

A

hemocyanin

194
Q

How is hemocyanin different from hemoglobin?

A

uses copper instead of iron to bind O2; not associated with blood cells but is intend a free protein in the circulating fluid (hemolymph) of arthropods and some mollusks

195
Q

What percentage of hemoglobin is oxygenated at PO2 = 100 mmHg when leaving the alveoli?

A

97% of hemoglobin is oxygenated

196
Q

What percentage of hemoglobin is oxygenated at PO2 = 40 mmHg in blood that returns to the heart through the systemic veins?

A

75% of hemoglobin is oxygenated

197
Q

How much of a “reserve” of O2 is there in hemoglobin?

A

In a person at rest, only about 22% of oxyhemoglobin proteins release oxygen, meaning that 78% of oxygen is left as a reserve

198
Q

Why is the large reserve of O2 in hemoglobin important?

A

enables blood to supply needs during exertion AND rest; ensures there’s enough O2 to maintain life for 4-5 min if breathing is interrupted/heart stops pumping

199
Q

What is the PO2 of venous blood during exercise?

A

can drop to 20 mm Hg

200
Q

A second oxygen reserve is found in

A

myoglobin

201
Q

Where is myoglobin found?

A

muscle cells

202
Q

Myoglobin consists of

A

a single polypeptide chain w/ iron atom

203
Q

Which has a higher affinity for O2 - myoglobin or hemoglobin?

A

myoglobin

204
Q

How does myoglobin function as a backup?

A

when hemoglobin levels are exhausted, myoglobin kicks in with extra O2

205
Q

How can animals like the elephant seal stay underwater for long periods of time (in terms of hemoglobin/myoglobin)?

A

because they have high levels of O2 stored in myoglobin in their muscle cells

206
Q

CO2 + H2O yields

A

H2CO3

207
Q

H2CO3 dissociates into

A

HCO3- and H+

208
Q

Where does H2CO3 dissociation occur?

A

inside RBCs

209
Q

What effect does a lower pH have on hemoglobin’s affinity for oxygen?

A

promotes release of O2; shifts Bohr curve to the right

210
Q

What effect does a higher temperature have on hemoglobin’s affinity for oxygen?

A

promotes release of O2; shifts curve to the right

211
Q

What percentage of CO2 is simply dissolved in plasma?

A

8% of blood CO2 is simply dissolved in plasma

212
Q

What percentage of blood CO2 is bound to hemoglobin?

A

20% of blood CO2 is bound to hemoglobin

213
Q

Where does CO2 bind to in hemoglobin?

A

on the protein part (not to the iron parts), so it doesn’t compete with O2

214
Q

What effect does CO2 binding to hemoglobin have on binding to O2?

A

CO2 binding causes hemoglobin’s shape to change which lowers affinity for O2

215
Q

Where is CO2 not dissolved in plasma or bound to hemoglobin found?

A

diffuses into RBCs where it combines with H2O to produce H2CO3

216
Q

Which enzyme catalyzes the combining of CO2 and H2O?

A

carbonic anhydrase

217
Q

What happens to the H+ that results from the dissociation of H2CO3?

A

H+ binds to deoxyhemoglobin

218
Q

What happens to the HCO3- that results from the dissociation of H2CO3?

A

moves out of RBC into plasma via a transporter that exchanges one Cl- for one HCO3-

219
Q

What is the chloride shift?

A

when an HCO3- inside an RBC is replaced with a Cl- via a transporter

220
Q

CO2 is primarily transported in what form?

A

as HCO3-

221
Q

Why is the diffusion of CO2 into the RBCs important?

A

it creates a diffusion gradient that allows more CO2 to move into the plasma from surrounding tissues

222
Q

What is the major buffer of blood plasma?

A

HCO3-

223
Q

What happens to H2CO3 in the lungs?

A

the lower PCO2 causes carbonic anhydrase reaction to proceed in the reverse reaction, which creates H2O and CO2, and CO2 diffuses out and is released in the next exhalation

224
Q

Which two other gases can be transported by hemoglobin?

A

NO and CO

225
Q

NO is important for

A

vessel dilation

226
Q

Why is CO poisonous?

A

because it binds more strongly to hemoglobin than does O2

227
Q

Victims of CO poisoning often have what color skin?

A

bright red skin

228
Q

What happens to HCO3- replaced with Cl- once the blood reaches the alveolar capillaries?

A

diffuses into cell, reacts with H+ to form H2CO3, then decomposes into CO2 + H2O, diffuses into alveolus, exhaled

Biology 2312 (11 decks)

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