Transcript The Body in Motion - Southwestern Adventist University
Biology, Seventh Edition
Chapter 44 Gas Exchange
Solomon • Berg • Martin
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 44 Gas Exchange
• Respiration
• The exchange of gases between an organism and its environment • Organismic respiration – Takes place in animals – O 2 taken up and CO 2 excreted • Aerobic cellular respiration – Takes place in mitochondria – O 2 is necessary for citric acid cycle Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 44 Gas Exchange
• Simple diffusion
• Passive movement of particles from a region of higher concentration to a region of lower • Provides gas exchange for small, aquatic organisms such as sponges, hydras, and flatworms Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 44 Gas Exchange
• Comparison of gas exchange in air and water
• Air – Contains a higher concentration of molecular oxygen than water – Oxygen diffuses more rapidly through air than water – Less energy needed to move air over gas exchange surface Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 44 Gas Exchange
• Adaptations for gas exchange
• Body surface – Small aquatic animals exchange gases by diffusion, requiring no specialized respiratory structures – Some invertebrates, including most annelids, and many amphibians exchanges gases across the body surface Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 44 Gas Exchange
Gas exchange across body surface Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 44 Gas Exchange
• Adaptations for gas exchange, cont’d
• Trachae – In insects and some other anthropods, air enters trachae through openings called spiracles – Trachae branch and extend to all regions of the body Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 44 Gas Exchange
Gas exchange across tracheal tubes Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 44 Gas Exchange
• Adaptations for gas exchange, cont.
• Gills – Moist, thin projections of the body surface found mainly in aquatic animals – Countercurrent exchange system maximizes O 2 into the blood and CO 2 out of the blood Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
Gas exchange across gills
CHAPTER 44 Gas Exchange
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 44 Gas Exchange
• Adaptations for gas exchange, cont.
• Lungs – Terrestrial vertebrates have lungs and some means of ventilating them – Lungs are respiratory structures that develop as ingrowths of body surface or from wall of a body cavity Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
Gas exchange across lungs
CHAPTER 44 Gas Exchange
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
Comparison of vertebrate lungs
CHAPTER 44 Gas Exchange
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Biology, Seventh Edition
How bird lungs function
CHAPTER 44 Gas Exchange
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Biology, Seventh Edition CHAPTER 44 Gas Exchange
• Mammalian respiratory system
• Includes the lungs and airways • Lung occupies pleural cavity and is covered with a pleural membrane • Breath of air passes in sequence – Nostrils, nasal cavities, pharynx, larynx, trachea, bronchi, bronchioles, and alveoli Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
The human respiratory system
CHAPTER 44 Gas Exchange
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Biology, Seventh Edition
Structure of alveoli
CHAPTER 44 Gas Exchange
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Biology, Seventh Edition CHAPTER 44 Gas Exchange
• Mechanics of breathing
• Diaphragm contracts and chest cavity expands • Respiratory centers in the medulla and pons regulate respiration – Stimulated by chemoreceptors – An increase in hydrogen ions and low oxygen concentration Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
Mechanics of breathing
CHAPTER 44 Gas Exchange
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 44 Gas Exchange
• Role of hemoglobin in oxygen transport
• Respiratory pigment in vertebrate blood • Almost 99% of the O 2 in human blood is transported as oxyhemoglobin (HbO 2 ) Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 44 Gas Exchange
Gas exchange in the lungs and tissues Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 44 Gas Exchange
• Oxygen-carrying capacity
• Maximum amount of O 2 that can be transported by hemoglobin
• Oxygen content
• Actual amount of O 2 hemoglobin bound to
• Percent oxygen saturation
• Ratio of O 2 content to O 2 capacity carrying Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 44 Gas Exchange
• Oxygen-hemoglobin dissociation curve
• Shows that as O 2 concentration increases, there is progressive increase in hemoglobin that combines with O 2
• Bohr effect
• Oxyhemoglobin dissociates more readily as CO 2 increases Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 44 Gas Exchange
Oxygen-hemoglobin dissociation curves Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
Carbon dioxide transport
CHAPTER 44 Gas Exchange
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 44 Gas Exchange
• Hyperventilation
• Reduces the concentration of CO 2 in the alveolar air and the blood
• Decompression in divers
• Rapid decrease in barometric pressure can cause decompression sickness • Diving mammals have high concentrations of myoglobin Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
Deep diver
CHAPTER 44 Gas Exchange
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 44 Gas Exchange
• Affects of pollution on the respiratory system
• Ciliated mucous lining traps inhaled particles • Inhaling polluted air results in bronchial constriction – Increased mucous secretion – Damage to ciliated cells – Coughing Copyright © 2005 Brooks/Cole — Thomson Learning