Post on 21-Jun-2020
UNIFYING CONCEPTS OF ANIMAL CIRCULATION
• Every organism must exchange materials with its
environment, relying upon
– diffusion, the spontaneous movement of molecules from an area of higher concentration to an area of lower concentration, and
– a circulatory system, which facilitates the exchange of materials for all but the simplest animals.
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6 Open and Closed Circulatory Systems
• Circulatory systems typically consist of a
– central pump,
– vascular system, and
– circulating fluid.
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• In an open circulatory system,
– the heart pumps blood into large open-ended vessels and
– fluid circulates freely among cells.
• Open circulatory systems are found in many
invertebrates, including
– arthropods and
– most molluscs.
Open and Closed Circulatory Systems
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• In a closed circulatory system, blood
– stays within a set of tubes and
– is distinct from the interstitial fluid, the fluid that fills the spaces around cells.
• Closed circulatory systems are found in
– many invertebrates, including earthworms and octopuses, and
– vertebrates.
Open and Closed Circulatory Systems
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Figure 23.1
(a) Open circulatory system (b) Closed circulatory system
Tubularheart
Circulating fluid
Interstitial fluidHeart
Heart
Vessels
VesselsCapillaries
Artery(O2-richblood)
Artery(O2-poor blood)
Vessels
CapillariesArteriole
Venule
Vein
HeartVentricle
Atrium
10 Figure 23.1a
(a) Open circulatory system
Tubularheart
Circulating fluid
Heart
Vessels
11
Figure 23.1b
(b) Closed circulatory system
Interstitial fluid
Heart
VesselsCapillaries
Artery(O2-richblood)
Artery(O2-poor blood)
Vessels
CapillariesArteriole
Venule
Vein
HeartVentricleAtrium
12
• The cardiovascular system of vertebrates
consists of the
– heart and
– blood vessels.
• In the heart,
– the atrium receives blood and
– the ventricle pumps blood away from the heart.
Open and Closed Circulatory Systems
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• Blood is confined to three main types of blood
vessels:
1. Arteries carry blood away from the heart into smaller arterioles as they approach the organs.
2. Capillaries are the site of exchange between blood and interstitial fluid.
3. Venules collect blood from the capillaries and converge to form veins, which return blood back to the heart.
Open and Closed Circulatory Systems
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14 UNIFYING CONCEPTS OF ANIMAL RESPIRATION
• Cellular respiration
– uses oxygen and glucose and
– produces water, carbon dioxide, and energy in the form of ATP.
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UNIFYING CONCEPTS OF ANIMAL RESPIRATION
• Cells using cellular respiration
– need a steady supply of oxygen and
– must continuously dispose of CO2.
• The respiratory system promotes this gas
exchange.
99 Figure 23.UN01
Environment
Cell
Glucose Oxygen Water EnergyCellular
respiration Carbon
dioxide
C6H12O66 O2 6 CO2 6 H2O ATP
CO2O2
100
The Structure and Function of Respiratory Surfaces
• Animals can get oxygen from
– the atmosphere, which contains about 21% oxygen, and
– bodies of water, which contain about 3–5% oxygen.
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101 The Structure and Function of Respiratory Surfaces
• Gas exchange occurs at the respiratory surface, which must be
– large enough to take up oxygen for every cell in the body and
– adapted to the lifestyle of the organism.
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• Moist skin is used as a respiratory surface in
earthworms.
• In aquatic environments, the main respiratory
surfaces are
– skin and
– extensions of the body surface called gills.
The Structure and Function of Respiratory Surfaces
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103 Figure 23.15
Cross section ofrespiratory surface (the skin covering the body)
Respiratorysurface (gill)
Body surface
CapillariesCapillariesCO2
CO2
O2O2
(a) Skin (b) Gills
104
Figure 23.15a
Cross section ofrespiratory surface (the skin covering the body)
CapillariesCO2
O2
(a) Skin
105 Figure 23.15b
Respiratorysurface (gill)
Body surface
Capillaries
CO2
O2
(b) Gills
106
• In most land-dwelling animals, the respiratory
surfaces are
– folded into the body and
– open to the air only through narrow tubes.
The Structure and Function of Respiratory Surfaces
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• Insects breathe using a tracheal system, an
extensive network of internal tubes called
tracheae that
– branch throughout the body and
– extend to nearly every cell.
The Structure and Function of Respiratory Surfaces
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Figure 23.16
Respiratory
surface
(tracheae)
Body cells(no capillaries)
Respiratory
surface
(within lung)
Body
surface
Body
surface
Capillary
(a) Tracheae (b) Lungs
CO2
CO2
CO2
O2
O2
O2
109 Figure 23.16a
Respiratory
surface
(tracheae)
Body cells(no capillaries)
Body
surface
(a) Tracheae
CO2
O2
110
Figure 23.16b
Respiratory
surface
(within lung)
Body
surface
Capillary
CO2
CO2
O2
O2
(b) Lungs
111
• Lungs
– are located in only one part of the body and
– are the most common respiratory surface of snails, some spiders, and terrestrial vertebrates.
• The circulatory system transports gases between
the respiratory surface and the rest of the body.
The Structure and Function of Respiratory Surfaces
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Figure 23.17
Skin(entire body
surface)
Gills(extensions of the
body surface)
Tracheae(branching
internal tubes)
Lungs(localized
internal organs)
RESPIRATORY ORGANS
Moist skin of a leech Gills of a sea slugTracheae of a silkmoth caterpillar
Model of a pair ofhuman lungs
Tracheae(internaltubes)
Gills
113 Figure 23.17a
Skin(entire body surface)
Moist skin of a leech
114
Figure 23.17b
Gills(extensions of the
body surface)
Gills of a sea slug
Gills
115 Figure 23.17c
Tracheae(branching
internal tubes)
Tracheae of a silk moth
caterpillar
Tracheae(internaltubes)
116
Figure 23.17d
Lungs(localized
internal organs)
Model of a pair of human lungs
117 THE HUMAN RESPIRATORY SYSTEM
• The human respiratory system has three phases
of gas exchange:
1. breathing, the ventilation of the lungs by alternate inhalation and exhalation,
2. transport of oxygen from the lungs to the rest of the body via the circulatory system, and
3. diffusion of oxygen from the blood and release of CO2 into the blood by cells of the body.
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Figure 23.18-1
Circulatory system
Breathing
Lung
CO2
O2 1
119 Figure 23.18-2
Circulatory system
Breathing
Lung
CO2
O2
Transport of gases bythe circulatory system
2
1
120
Figure 23.18-3
Circulatory system
Breathing
Lung
CO2
O2
Transport of gases bythe circulatory system
Exchange of gaseswith body cells
Mitochondria
Capillary
Cell
CO2
O2
2
1
3
121