Transcript Understanding Our Environment - McGraw Hill Higher Education

Circulation and Respiration
Chapter 23
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Outline
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Open vs. Closed Circulation Systems
Vertebrate Circulatory System Functions
Architecture of Vertebrate Circulatory System
 Fish Circulation
 Amphibian and Reptile Circulation
 Mammalian and Bird Circulation
Heart Contraction
Cardiovascular Diseases
Respiration
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Open and Closed Circulatory Systems
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Cnidarians have cells directly exposed to
external environment or to a body cavity
(gastrovascular cavity) functioning in
digestion and circulation.
Larger animals transport oxygen and
nutrients from the environment and digestive
cavity to body cells by internal fluid within a
circulatory system.
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Open and Closed Circulatory Systems
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Open circulatory system - No distinction
between circulating fluid and extracellular
fluid of the body tissues (hemolymph).
Closed circulatory system - Circulating fluid
(blood) is always enclosed within vessels
that transport blood away from, and back to,
a pump (heart).
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Open and Closed Circulatory Systems
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Arteries - Carry blood away from the heart.
Veins - Return blood to heart.
 Capillaries - Pass blood between arterial
and venous system.
As blood plasma passes through capillaries,
pressure forces fluid (interstitial fluid) out
capillary walls.
 Returns to capillaries, and lymph vessels.
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Animal Kingdom Circulatory Systems
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Vertebrate Circulatory System Functions
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Transportation
 Respiratory
 Nutritive
 Excretory
Regulation
 Hormone Transport
 Temperature Regulation
- Counter-current heat exchange
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Vertebrate Circulatory System Functions
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Protection
 Blood Clotting
 Immune Defense
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Architecture of Vertebrate Circulatory System
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Heart (Pump)
Blood Vessels (Tube network)
Blood (Circulating fluid)
 Leaves heart through arteries
 Passes into arterioles
 Forced through capillaries
 Passes to venules
 Flows to veins
 Back to heart
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Architecture of Vertebrate Circulatory System
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Decrease in blood vessel size causes
frictional resistance as fluid passes over walls.
 Heart must overcome high resistance in
capillary network.
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Architecture of Vertebrate Circulatory System
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Arteries
 Blood comes from heart in large pulses,
thus artery must be able to expand.
- Innermost layer composed of endothelial
cells, surrounded by a thick layer of
smooth muscle and elastic fibers.
Arterioles
 Smaller in diameter than arteries, and
surrounding muscle can be relaxed to
enlarge diameter.
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Architecture of Vertebrate Circulatory System
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Capillaries
 Transport oxygen and food from blood to
body’s cells and pick up waste carbon
dioxide.
- Thin walls allow gas diffusion.
Veins
 Return blood to heart
 Thin layers of muscles and elastic fibers
 Unidirectional valves
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Blood Vessel Structure
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Lymphatic System
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Cardiovascular system is very leaky.
 Lymphatic system uses second circulatory
system to gather liquid (lymph) .
- Returns proteins to circulation.
- Transports fats absorbed from intestine.
- Aids in body’s defense.
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Human Lymphatic System
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Blood
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Blood composed of plasma and several
types of circulating cells.
Plasma Components
 Metabolites and Wastes
 Salts and Ions
 Proteins
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Blood
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Circulating Cells
 Erythrocytes (Red blood cells) Carry
hemoglobin, and thus oxygen, to cells.
 Leukocytes (White blood cells)
- Neutrophils
- Macrophages
- Lymphocytes
 B cells - produce antibodies
 T cells - attack invading bacteria
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Blood
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Platelets
 Help blood to clot.
- Large cells within bone marrow
(megakaryocytes) pinch off bits of
cytoplasm.
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Fish Circulation
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Fish heart is a four-chambered tube.
 First two, sinus venosus and atrium are
collection chambers, while second two,
ventricle and conus arteriosus are pumping
chambers.
 Gill respiration delivers fully oxygenated
blood to the body, but circulation is
sluggish, limiting rate of oxygen delivery.
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Heart and Circulation of a Fish
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Amphibian and Reptile Circulation
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Advent of lungs resulted in two circulations:
 Pulmonary circulation - (Lungs)
 Systematic circulation - (Rest of body)
Amphibian heart has two two structural
features to reduce mixing of oxygenated and
deoxygenated blood.
 Atrium divided into two chambers.
 Conus arteriosus partially separated by
septum.
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Amphibian Heart and Reptile Circulation
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Mammalian and Bird Circulation
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Mammals, birds, and crocodiles have fourchambered heart made up of two pumping
systems.
 Oxygenated blood from lungs empties into
left atrium through pulmonary veins.
- From atrium, flows into left ventricle.
 Ventricle contracts and forces blood
out in a single strong pulse.
 Mitral valve prevents back-flow.
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Mammalian and Bird Circulation
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Blood within contracting left ventricle moves
into aorta.
 Separated from left ventricle by one - way
aortic valve.
Blood eventually returns to heart.
 Superior Vena Cava drains upper body.
 Inferior Vena Cava drains lower body.
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Mammalian and Bird Circulation
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Right Side
 Blood passes from right atrium into right
ventricle through one-way tricuspid valve.
 Passes out contracting ventricle through
pulmonary valve into pulmonary arteries.
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Heart Contraction
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Heartbeat originates in sinoatrial (SA) node.
 Membranes spontaneously depolarize.
- Depolarization passes to ventricles
through atrioventricular (AV) node.
 Bundle of His
 Purkinje Fibers
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Monitoring Heart’s Performance
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Listen to heart at work
 If valves are not fully opening or closing,
turbulence is created and can be heard as
a heart murmur.
Measure Blood Pressure
 Diastolic (Low point)
 Systolic (High point)
Measure Depolarization
 Magnitude of electrical pulse.
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Cardiovascular Diseases
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Heart Attacks
 Blood clot in coronary arteries.
- Angina pectoris
Strokes
 Interference with blood flow to brain.
Atherosclerosis
 Accumulation of fatty acids, smooth
muscle, cholesterol and cellular debris.
- Arteriosclerosis - Calcium deposits.
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Respiratory Systems
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Respiration - Uptake of oxygen and
simultaneous release of carbon dioxide.
 Gills (Aquatic organisms)
 Trachea (Terrestrial arthropods)
- Spiracles
 Lungs (Terrestrial vertebrates)
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Respiration in Aquatic Vertebrates
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A fish swimming continuously pushes water
through mouth and out gills.
 Permits countercurrent flow.
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Respiration in Terrestrial Vertebrates
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Amphibians obtain oxygen via lungs and can
respire through moist skin.
Reptiles need more oxygen, but cannot rely
on skin.
 Lungs contain many small air chambers
increasing surface area.
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Respiration in Terrestrial Vertebrates
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Mammals have large metabolic oxygen
demands due to maintenance of body
temperature.
 Alveoli - Small chambers in lung interior.
 Bronchiole - Passageways connecting
clusters of aveoli.
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Evolution of Vertebrate Lung
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Respiration in Terrestrial Vertebrates
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Bird Lungs
 Flying creates a large oxygen demand,
thus birds possess high lung efficiency.
- Air flows into the lungs in one direction.
 No dead volume - full oxygenation.
- Blood runs in different direction.
 Blood leaving lung can still contain
more oxygen than exhaled air.
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Bird Respiration
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Mammalian Respiratory System
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Pair of lungs hang free within thoracic cavity.
 Bronchus connects each lung to trachea.
- Air enters through nostrils (or mouth),
passes into larynx, and then into trachea.
 Passes down bronchus to lungs.
 Thoracic cavity bounded by diaphragm.
 Each lung covered with pleural membrane.
 Weight of lung supported in thoracic cavity
by interpleural fluid.
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Human Respiratory System
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Mechanics of Breathing
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During inhalation, muscular contraction
causes walls of chest cavity to expand, so
that rib cage moves outward and upward.
 Diaphragm flattens
 Internal air pressure decreases
During exhalation, ribs and diaphragm return
to original resting position, forcing air from
inner cavity back to atmosphere.
 Typical tidal volume (0.5) liters of air.
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Mechanics of Breathing
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Typical human breath at rest, tidal volume,
moves about (0.5) liters of air.
Lung still contains residual volume of air after
breath completed (1200 milliliters).
 Each exhalation removes approximately
same volume as inhalation added.
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Gas Exchange
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Oxygen moves within circulatory system
carried piggyback on hemoglobin.
Hemoglobin uptakes oxygen within red blood
cells, and causes diffusion from blood
plasma.
 Carbon dioxide in tissue speeds up
unloading of oxygen.
- Bohr Effect
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Gas Exchange
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As red blood cells are unloading oxygen,
they are also absorbing carbon dioxide from
the tissue.
 To keep carbon dioxide from diffusing out
of red blood cells back into plasma,
carbonic anhydrase combines with carbon
dioxide and water to form carbonic acid.
Hemoglobin also has ability to hold and
release nitric oxide.
 Regulates blood pressure and blood flow.
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Nature of Lung Cancer
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One of leading causes of death among
adults in the world.
 Most carcinogens are also mutagens.
Tumor Suppressor Genes
 Rb protein - acts as brake on cell division.
 P53 protein - inspects DAN prior to
division.
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Smoking Causes Lung Cancer
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Cigarette smoke contains many mutagens:
 Benzo[a]pyrene binds to three sites on p53
and causes mutations at the inactivation
sites.
- Research found p53 gene inactivated in
70% of all lung cancers.
- Nicotine is an addictive drug.
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Review
•
•
•
•
•
•
Open vs. Closed Circulation Systems
Vertebrate Circulatory System Functions
Architecture of Vertebrate Circulatory System
 Fish Circulation
 Amphibian and Reptile Circulation
 Mammalian and Bird Circulation
Heart Contraction
Cardiovascular Diseases
Respiration
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies
Copyright © McGraw-Hill Companies Permission required for reproduction or display
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies