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LECTURE PRESENTATIONS
For CAMPBELL BIOLOGY, NINTH EDITION
Jane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson
Chapter 42
Circulation and Gas Exchange
Lectures by
Erin Barley
Kathleen Fitzpatrick
© 2011 Pearson Education, Inc.
Chapter 42 Warm-Up
1. How does the heart beat?
2. What are the 3 types of blood cells and
their function?
3. What is the function of the lymphatic
system?
4. List the pathway of one molecule of O2
from the air into your pinky toe.
What you need to know:
• General characteristics of a respiratory
surface
• How O2 and CO2 are transported in
blood
• Pathway of O2 from airRBCtissues
Respiration
• Gas exchange supplies O2 for cellular respiration
and disposes of CO2
• Partial pressure = pressure exerted by a
particular gas in a mixture of gases
• Gases always diffuse from higher partial pressure
 lower partial pressure
© 2011 Pearson Education, Inc.
• Respiratory media: O2 in air or water
• Respiratory surface: body wall, skin, gills,
tracheae, lungs
• Characteristics:
– Moist
– Large surface area-to-volume ratio
– Larger animals: associated with vascular
system
© 2011 Pearson Education, Inc.
Gills in aquatic animals
Coelom
Gills
Parapodium
(functions as gill)
(a) Marine worm
Gills
Tube foot
(b) Crayfish
(c) Sea star
Fish gills: absorb O2 through countercurrent
exchange (blood flows opposite of water)
Tracheal systems in insects
Mammalian respiratory system
Pathway of O2
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•
•
•
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Nose/mouth: filtered, warmed, humidified
Pharynx
Larynx: contains vocal cords
Trachea: windpipe; lined with cartilage
Bronchi: branches to lungs
Bronchioles
Alveoli: air sacs for gas exchange
• Mucus: traps particles
• Cilia: sweeps particles up to pharynx
Alveoli
Figure 42.30a
1 Inhaled air
8 Exhaled air
Alveolar
epithelial
cells
2 Alveolar
spaces
CO2
O2
Alveolar
capillaries
7 Pulmonary
arteries
3 Pulmonary
veins
6 Systemic
veins
4 Systemic
arteries
Heart
CO2
O2
Systemic
capillaries
5 Body tissue
(a) The path of respiratory gases in the circulatory
system
Diaphragm: dome-shaped muscle
separating thoracic/abdominal cavities
Control of Breathing in Humans
• Control center =
medulla oblongata
• Responds to pH
changes in blood
• High CO2  carbonic
acid forms  lowers pH
• Sensors in the aorta
and carotid arteries
© 2011 Pearson Education, Inc.
Adaptations for gas exchange
• Hemoglobin: respiratory pigment in vertebrates
– 4 subunits, each with heme group with iron (Fe)
– Can carry 4 molecules of O2
– Bohr shift: O2 dissociates from hemoglobin
when blood pH is low
• Arthropods, mollusks:
– blue hemocyanin pigment
– contains copper (Cu)
© 2011 Pearson Education, Inc.
How CO2 is transported
1. Bicarbonate ions (70%)
2. Hemoglobin (23%)
3. Dissolved in plasma (7%)
© 2011 Pearson Education, Inc.
Respiratory Adaptations of Diving Mammals
– Weddell seals in Antarctica can remain
underwater for 20 minutes to an hour
– , elephant seals can dive to 1,500 m and remain
underwater for 2 hours
• High blood to body volume ratio
• Stockpile O2 and deplete it slowly
• Store oxygen in their muscles in myoglobin
proteins
© 2011 Pearson Education, Inc.
Respiratory Disorders
• Asthma: airways constricted
• Bronchitis: bronchi swollen and clogged
• Pneumonia: inflammation of lung caused
by infection
• Tuberculosis (TB): infectious disease
caused by M. tuberculosis
• Emphysema: lose elasticity of lung tissue
• Lung Cancer: abnormal cell growth in lungs