Gas Exchange Systems Flashcards Preview

Life Science 2 > Gas Exchange Systems > Flashcards

Flashcards in Gas Exchange Systems Deck (141):
1

-- are made up of gas exchange surfaces and the mechanisms that ventilate and perfuse those surfaces

gas exchange systems

2

cells need to obtain oxygen from the environment to produce an adequate supply of -- by cellular respiration

ATP

3

CO2 is a -- product of cellular respiration and it must be removed from the body to prevent toxic effects

end

4

- is the only means by which respiratory gases are exchanged between an animal's internal body fluids and the outside medium

diffusion

5

the total number os gas molecules in a specified volume depends on --

pressure

6

atmospheric pressure at sea level is

760 mm of mercury

7

Because dry air is 20.9% O2, the -- at sea level is 20.9% of 760 mm Hg or about 159 mm Hg

partial pressure of oxygen

8

the actual amount of gas in a liquid depends on the partial pressure of that gas in the gas phases in contact with the liquid as well as on the -- of that gas in that liquid

solubility

9

the rate at which a gas such as oxygen diffuses between two locations

Q

10

D is the -- which is a characteristic of the diffusing substance, the medium, and the temperature

diffusion coefficient

11

all substances diffuse faster at -- temperatures and faster in air than in water

higher

12

cross-sectional area through which the gas is diffusing

A

13

P1 and P2 are the -- of the gas at the two locations

partial pressures

14

the path length or distance between the two locations

L

15

(P1 -P2)/L is a

partial pressure gradient

16

Animals maximize D for respiratory gases by using -- rather than -- as their gas exchange medium

air rather than water

17

true or false: the slow diffusion of oxygen molecules in water affects both air-and water- breathing animals

true

18

oxygen content of air is much -- than the oxygen content of an equal amount of water

higher

19

oxygen diffuses more -- in air than in water

rapidly

20

animals has to do -- to mover water or air over its gas exchange surfaces; more energy is required to move the denser water

work

21

fish need more oxygen when water is warmer but warm water carries -- oxygen than cold water

less

22

-- decreases with altitude

oxygen availability

23

the partial pressure of CO2 in the atmosphere is close to -- both and sea level and atop Mount Everest

zero

24

getting rid of CO2 is not a problem for water breathing animals because CO2 is much more -- in water than O2

soluble

25

-- surface area for gas exchange

increase

26

-- partial pressure difference driving diffusion

maximize

27

-- the diffusion path length

minimize

28

-- the diffusion that takes place in an aqueous medium

minimize

29

highly branched and folded extensions of the body surface that provide a large surface area for gas exchange with water; found in larval amphibians and insects

external gills

30

very thin tissues in gills and lungs reduce the

diffusion path length

31

external gills are vulnerable to damages so many animals evolved -- for gills

protective body cavities

32

are internal cavities for respiratory gas exchange with air

lungs

33

lungs have a large surface area because they are highly -- and because they are elastic they can be -- with air and deflated

divided; inflated

34

actively moving the external medium (air or water) over the gas exchange surfaces regularly exposes those surfaces to fresh respiratory medium containing max CO2 and O2 concentrations

ventilation

35

actively moving the internal medium (blood) over the internal side of the exchange surfaces transports CO2 to those surfaces and O2 away from them

perfusion

36

insects' -- system have airways throughout their bodies

tracheal

37

insect respiratory system communicates with the outside environment though gated openings called -- in the side of the abdomen

spiracles

38

spiracles open to allow gas exchange and then close to decrease --

water loss

39

spiracles open into tubes called tracheae that branch into even finer tubes or tracheoles which end in tiny -- that are the actual gas exchange surfaces

air capillaries

40

in insect's -- are close to an air capillary

highly active tissues

41

fish gills use - flow to maximize gas exchange

countercurrent

42

internal gills of fish are supported by -- that lie between the mouth cavity and the protective opercular flaps on the sides of the fish just behind the eyes

gill arches

43

water flows -- into the fish's mouth, over the gils and out from under the opercular flaps

unidirectionally

44

true or false: fish gills are continuously bathed with fresh water maximizing PO2 on the external gill surfaces

true

45

on the internal side of the gill membranes, the circulation of blood -- the PO2 by sweeping O2 away as rapidly as it diffuses

minimizes

46

each gill consists of 100s of ribbonlike --

gill filaments

47

the upper and lower flat surfaces of each gill filament are covered with rows of evenly spaced folds called

lamellae

48

gas exchange surfaces for fish

lamellae

49

-- blood vessels bring deoxygenated blood to the gills

afferent

50

-- blood vessels take oxygenated blood away from the gills

efferent

51

blood perfusion of the lamellae is -- to the flow of water over the lamellae

countercurrent

52

some fish (anchovies, tuna, certain sharks) ventilate their gills by -- with their mouths open

constantly swimming

53

most fish ventilate their gills by a

two-pump mechanism

54

lungs of a bird are - than the lungs of a similar-sized mammal

smaller

55

bird lungs are -- during inhalation and -- during exhalation

compressed during inhalation
expand during exhalation

56

the remaining air in lungs and airways after exhalation

dead space

57

air flow -- through the lungs in birds

unidirectionally

58

birds have very little -- and the fresh incoming air is not mixed with stale air

dead space

59

birds have -- at several locations in their bodies

air sacs

60

in birds, -- receive inhaled air but are not gas exchange surfaces

air sacs

61

trachea --> bronchi --> parabronchi --> tiny __

air capillaries

62

the gas exchange surface in birds

air capillaries

63

a single breath remains in a bird's gas exchange system for -- cycles of inhalation and exhalation

2

64

in birds, inhalation -- the sacs

expands

65

in birds, exhalation -- the sacs

compresses

66

birds can supply their gas exchange surfaces with a continuous flow of fresh air that has a -- close to that of the ambient air

PO2

67

In birds, even when the PO2 of the ambient air is only slightly above that of the blood O2 can - from air to blood

diffuse

68

-- ventilation produces dead space that limits gas exchange efficiency

tidal

69

lungs evolved as out pockets of the --

digestive tract

70

air flows in and exhaled gases flow out by the same route

tidal ventilation

71

normal amount of air that moves in and out per breath when at rest

tidal volume (TV)

72

When we breathe in as much as possible, the additional volume is

inspiratory reserve volume (IRV)

73

additional air that can be forcefully exhaled

expiratory reserve volume (ERV)

74

the maximum capacity for air exchange in one breather = TV + IRV + ERV

vital capacity

75

dead space is also called

residual volume (RV)

76

ERV + RV =

functional residual volume

77

RV is important because it contributes to the FRC and to the -- of oxygen in inhaled air

dilution

78

trachea's thin walls are prevented from collapsing by C-shaped bands of -- as air pressure changes during the breathing cycle

cartilage

79

human site of gas exchange

alveoli

80

because the airways conduct air only to and from the alveoli and do not themselves participate in gas exchange their volume is

dead space

81

where -- meets alveolus very little tissue separates them so the length of diffusion path between air and blood is less than 2 micrometers

capillary

82

a condition in which inflammation damages and eventually destroys the walls of the alveoli and the 4th leading cause of US deaths

emphysema

83

emphysema: lungs have fewer but larger alveoli, RV -- and lungs lose elasticity

increases

84

mammalian lungs secrete -- and -- that do not directly influence gas exchange but rather aid ventilation

mucus and surfactant

85

lining the airways cilia continually beats sweeping mucus, with its trapped debris, up toward the pharynx where it can be swallowed or spit out

mucus escalator

86

substance that reduces the surface tension of a liquid

surfactant

87

gives the surface of a liquid properties of an elastic membrane

surface tension

88

fatty, detergent-like substance that is critical for reducing the work necessary to inflate lungs

lung surfactant

89

certain cells in the alveoli release surfactant molecules when they are --

stretched

90

lungs are ventilated by -- in the thoracic cavity

pressure changes

91

the lungs lie within the -- which is bounded by the ribs and the diaphragm

thoracic cavity

92

each lung is covered by a continuous sheet of tissue called the -- that also lines the thoracic cavity adjacent to that lung

pleural membrane

93

air enters the lungs from the -- via the trachea and bronchi and eventually reaches the alveoli

oral cavity or nasal passages

94

there is no real space between the pleural membranes of the lung and the thoracic cavity but there is a thin --

film of fluid

95

pleural membranes cannot separate because of the -- of the thin film of fluid between them, they pull on the lungs

surface tension

96

true or false: lungs are a closed cavity

false: they actually have an airway to the atmosphere and can expand

97

between the ribs are two sets of

intercostal muscle

98

expand the thoracic cavity by lifting the ribs up and outward

external intercostal muscles

99

decrease the volume of the thoracic cavity by pulling the ribs down an inward

internal intercostal muscles

100

inhalation is an -- process spurred by contraction of the diaphragm

active

101

exhalation is generally a -- process as the diaphragm relaxes

passive

102

there is always -- pressure in the pleural cavity which is the space between the pleural membranes

negative

103

during inhalation: diaphragm -- thoracic cavity expands, intrapleural pressure becomes more negative, lungs expand, air rushes in

contracts

104

during exhalation: diaphragm - thoracic cavity contracts, intrapleural pressure becomes less negative, lungs contact, gases are expelled

relaxes

105

Ventilation and perfusion work together to maximize the -- across the gas exchange surface

partial pressure gradients

106

ventilation deliver -- to the environmental side of the exchange surface where it diffuses across and is swept away by the perfusing blood which carries it to the tissue that need it

oxygen

107

perfusion delivers -- to the exchange surface where it diffuse out and is swept away by ventilation

carbon dioxide

108

red blood cells contain enormous amount of --

hemoglobin molecules

109

an iron-containing ring structure that can reversible bind a molecule of oxygen

heme group

110

hemoglobin's ability to pick up or release oxygen depends on the -- in its environment

PO2

111

as the blood circulates around the body, it releases only about -- in four of the O2 molecules it carries

one

112

hemoglobin keeps 75% of it O2 in reserve to meet the peak demands of --

highly active tissues

113

CO bind to hemoglobin with a 230-fold higher -- than oxygen

affinity

114

the average PO2 of deoxygenated blood returning to the heart is

40 mm Hg

115

the PO2 of blood leaving the lungs is about

100 mm Hg

116

25% of the O2 in arterial blood is released to tissues during -- or light exercise

rest

117

an oxygen reserve of 75% is helm by the hemoglobin and can be released to tissues with a low --

PO2

118

muscle cells have their own O2 binding molecule

myoglobin

119

myoglobin consists of just -- polypeptide chain associated with an iron-containing ring structure that can bind one O2 molecule

one

120

myoglobin has a higher -- for O2 than hemoglobin does, so it picks up and hold O2 at PO2 values at which hemoglobin is releasing bound O2

affinity

121

human fetus has a form of hemoglobin consisting of two a-globin and two --

y-globin chains

122

fetal hemoglobin has a higher affinity for O2 than adult hemoglobin shifting the oxygen binding/dissociation curve to the

left

123

the influence of pH on the function of hemoglobin

Bohr effect

124

blood passes through metabolically active tissues picking up acidic metabolites --> blood pH falls --> hemoglobin release -- of its O2

more

125

low PO2 --> increase rate of glycolysis --> producing more -- which is an important regulator of hemoglobin function

2,3-Bisphosphoglyceric acid

126

Like, low pH BPG shifts the O2 binding/dissociation curve of mammalian hemoglobin to the -- (lowers hemoglobin's affinity for O2)

right

127

when humans go to high altitudes or exercise, their RBC are exposed to lower PO2 and the level of BPG goes up, making it -- for hemoglobin to deliver more O2 to tissues

easier

128

the reason fetal hemoglobin has a left-shifted O2binding/dissociation curve is that its y-globin chains have a -- affinity for BPG than the B-globin chains of adult hemoglobin

lower

129

most CO2 produced by tissues is transported to the lungs in the for of

bicarbonate ions (HCO3-)

130

When CO2 dissolves in water, some of it slowly reacts with the water molecules to form -- some of which then dissociates into a proton (H+) and a bicarbonate ion (HCO3-)

carbonic acid (H2CO3)

131

In the endothelial cells of the capillaries and in the RBC, the enzyme - speeds up the conversion of CO2 to H2CO3

carbonic anhydrase (only speeds up a reversible react but does not determine direction)

132

groups of respiratory motor neurons in the -- increase their firing rates just before an inhalation begins

medulla

133

a small amount of CO2 in the bloodstream stimulates a -- increase in breathing rate

large

134

a large drop in arterial O2 has -- effect on breathing rates

little

135

If the brainstem is cut below the pons but above the medulla, breathing --

continues but is irregular

136

if the spinal cord in the neck is severed, breathing

ceases

137

for water-breathing animals, -- is the primary feedback stimulus for gill ventilation

oxygen

138

chemoreceptors on the surface of the medulla are sensitive to the -- and -- of the cerebrospinal fluid

PCO2 and pH

139

chemoreceptors on large blood vessels leaving the heart are sensitive to the - in blood

oxygen

140

the real stimulus for breathing is

pH (although me measure PCO2)

141

carotid and aortic bodies are

chemosensors