Biology Sylvia S. Mader Michael Windelspecht Chapter 35 Respiratory Systems Lecture Outline See separate FlexArt PowerPoint slides for all figures and tables pre-inserted into PowerPoint without notes. 1 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1

Biology, 9th ed, Sylvia Mader Chapter 37 Outline Respiratory Systems 35.1 Gas Exchange Surfaces 35.2 Breathing and Transport of Gases 35.3 Respiration and Human Health 2

Biology, 9th ed, Sylvia Mader Chapter 37 35.1 Gas Exchange Surfaces Respiratory Systems Respiration results in gas exchange between the body’s cells and the environment In terrestrial vertebrates, respiration includes: Ventilation (i.e., breathing) External respiration - gas exchange between the air and the blood within the lungs Internal respiration - gas exchange between the blood and the tissue fluid

Biology, 9th ed, Sylvia Mader Chapter 37 Respiration Respiratory Systems Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. External Respiration lungs CO2 O2 CO2 O2 tissue cells Internal Respiration

Biology, 9th ed, Sylvia Mader Chapter 37 Gas Exchange Surfaces Respiratory Systems Gas exchange takes place by diffusion For external respiration to be effective, gas-exchange regions must be: Moist Thin Large in relation to body size Effectiveness of diffusion is enhanced by vascularization Delivery to cells is promoted by respiratory pigments (e.g., hemoglobin)

Biology, 9th ed, Sylvia Mader Chapter 37 Gas Exchange Surfaces Respiratory Systems Overview of Gas-Exchange Surfaces Gases of air can dissolve in water However, When saturated, water contains a small fraction of the O2 in same volume of air Water is much more dense than air Aquatic animals expend more energy to breathe than do terrestrial animals

Biology, 9th ed, Sylvia Mader Chapter 37 Gas Exchange Surfaces Respiratory Systems Hydras and planarians Small animals with a large surface area Most of their cells exchange gases directly with the environment Larger aquatic animals Often have gills Finely divided vascularized outgrowths of the body surface or pharynx Gills of bony fishes Outward extensions of pharynx Ventilation is brought about by combined action of the mouth and gill covers (opercula) Utilize a countercurrent exchange system to transfer oxygen from the environment to their blood

Biology, 9th ed, Sylvia Mader Chapter 37 Earthworm Respiratory Systems Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. dorsal blood vessel ventral blood vessel CO2 O2

Anatomy of Gills in Bony Fishes Biology, 9th ed, Sylvia Mader Anatomy of Gills in Bony Fishes Chapter 37 Respiratory Systems Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. operculum lamellae a. 900X Water passes out of the pharynx and over the finely divided gills. Water passes by the gill lamellae in a direction opposite to blood flow. Oxygen content of water is always higher than the oxygen content of the blood. O2-rich blood O2-poor blood Direction of H2O flow Direction of H2O flow lamellae water flow O2 movement 15% blood flow 40% 70% 100% 30% 5% 60% 90% blood flow gill arch lamella gill filaments gill filament b. c. d. (fish): © Dr. Jeffrey Isaacson, NebraskaWesleyan University; (gills): © David M. Phillips/Photo Researchers, Inc.

Biology, 9th ed, Sylvia Mader Chapter 37 Gas Exchange Surfaces Respiratory Systems Insects and other terrestrial arthropods A respiratory system consisting of branched tracheae Oxygen enters tracheae at spiracles Tracheae branch until they end in tracheoles that are in direct contact with body cells

Biology, 9th ed, Sylvia Mader Chapter 37 Gas Exchange Surfaces Respiratory Systems Terrestrial vertebrates have evolved lungs Vascular outgrowths from lower pharyngeal region Lungs of birds and mammals are elaborately subdivided All terrestrial vertebrates, except birds, use a ventilation mechanism whereby air moves in and out by the same route

Biology, 9th ed, Sylvia Mader Chapter 37 Gas Exchange Surfaces Respiratory Systems Lungs of Humans As air moves through upper respiratory system It is filtered to free it of debris Warmed Humidified When air reaches lungs It is at body temperature, and It is saturated with water

Biology, 9th ed, Sylvia Mader Chapter 37 Gas Exchange Surfaces Respiratory Systems Lungs of Humans Air passes from pharynx through the glottis Larynx and trachea Permanently held open by cartilage rings Facilitates movement of air When food is swallowed The larynx rises The glottis is closed by the epiglottis Backward movement of soft palate covers the entrance of nasal passages into the pharynx

Biology, 9th ed, Sylvia Mader Chapter 37 Gas Exchange Surfaces Respiratory Systems Lungs of Humans (continued) Trachea divides Forms two primary bronchi Bronchi enter the right and left lungs Bronchi branch until there are a great number of tiny bronchioles Each bronchiole terminates in an elongated space enclosed by alveoli

The Human Respiratory Tract Biology, 9th ed, Sylvia Mader The Human Respiratory Tract Chapter 37 Respiratory Systems Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. cilia goblet cell epithelial cell blood flow blood flow particle movement nasal cavity pulmonary arteriole nostril pulmonary venule pharynx mucus bronchiole epiglottis glottis air larynx tracheal lumen trachea bronchus b. Tracheal lining lobule bronchiole lung capillary network diaphragm alveoli a. The path of air c. Bronchiole and alveoli b: © Ed Reschke

35.2 Breathing and Transport of Gases Biology, 9th ed, Sylvia Mader Chapter 37 35.2 Breathing and Transport of Gases Respiratory Systems Breathing Inspiration in mammals Creation of negative pressure in lungs The rib cage is elevated The diaphragm contracts and lowers Thoracic pressure decreases to less than atmospheric pressure Atmospheric pressure forces air into the lungs

Breathing and Transport of Gases Biology, 9th ed, Sylvia Mader Chapter 37 Breathing and Transport of Gases Respiratory Systems Breathing Expiration in mammals Creation of positive pressure in lungs The rib cage is lowered The diaphragm rises Thoracic pressure increases to more than atmospheric pressure Forces air out the lungs

Breathing and Transport of Gases Biology, 9th ed, Sylvia Mader Chapter 37 Breathing and Transport of Gases Respiratory Systems Ventilation All terrestrial vertebrates, with the exception of birds, utilize a tidal ventilation mechanism for breathing Volume of thoracic cavity and lungs is increased by muscle contractions that lower the diaphragm and raise the ribs Create negative pressure in the thoracic cavity and lungs, and then air flows into the lungs during inspiration

Breathing and Transport of Gases Biology, 9th ed, Sylvia Mader Chapter 37 Breathing and Transport of Gases Respiratory Systems Ventilation (continued) Birds use a one-way ventilation mechanism in lungs Fresh air never mixes with used air Increases gas-exchange efficiency

Respiratory System in Birds Biology, 9th ed, Sylvia Mader Chapter 37 Respiratory System in Birds Respiratory Systems Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. inhalation trachea lung exhalation lung anterior air sacs posterior air sacs trachea lung 1 Inhalation: Air enters posterior air sacs. 2 Exhalation begins: Air enters lung. anterior air sacs inhaled air exhaled air anterior air sacs exhalation posterior air sacs 4 Exhalation ends: Air exits anterior air sacs. 3 Exhalation continues: Air enters anterior air sacs.

Breathing and Transport of Gases Biology, 9th ed, Sylvia Mader Chapter 37 Breathing and Transport of Gases Respiratory Systems Modifications of Breathing in Humans Normally, adults have a breathing rate of 12 to 20 ventilations per minute The rhythm of ventilation is controlled by a respiratory center in the medulla oblongata of the brain Sends out impulses to the diaphragm and intercostal muscles of the rib cage so that inspiration occurs When the respiratory center stops sending neuronal signals to the diaphragm and the rib cage, expiration occurs

Nervous Control of Breathing Biology, 9th ed, Sylvia Mader Chapter 37 Nervous Control of Breathing Respiratory Systems Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. brain respiratory center: automatically regulates breathing intercostal nerves: stimulate the intercostal muscles intercostal muscles phrenic nerve: stimulates the diaphragm diaphragm

Breathing and Transport of Gases Biology, 9th ed, Sylvia Mader Chapter 37 Breathing and Transport of Gases Respiratory Systems Gas Exchange and Transport Partial pressure The amount of pressure exerted by a gas Gases diffuse from areas of higher to lower partial pressure Ventilation causes the alveoli to have a higher partial pressure of oxygen and a lower partial pressure of carbon dioxide than the blood in the pulmonary capillaries This accounts for the exchange of gases in the lungs The opposite occurs in the tissues of the body

Breathing and Transport of Gases Biology, 9th ed, Sylvia Mader Chapter 37 Breathing and Transport of Gases Respiratory Systems Transport of Oxygen and Carbon Dioxide External Respiration Most oxygen entering the pulmonary capillaries from the alveoli combine with hemoglobin in red blood cells to form oxyhemoglobin Internal Respiration Oxyhemoglobin gives up oxygen, which diffuses out of the blood into the tissues where it is taken up by cells A small amount of carbon dioxide enters the blood from the tissues and binds with hemoglobin to form carbaminohemoglobin Most of the carbon dioxide is transported in the form of bicarbonate ion

Biology, 9th ed, Sylvia Mader Chapter 37 Hemoglobin Respiratory Systems Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. heme group iron atom beta chain alpha chain © Andrew Syred/Photo Researchers, Inc.

External and Internal Respiration Biology, 9th ed, Sylvia Mader External and Internal Respiration Chapter 37 Respiratory Systems Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. alveolus plasma HCO3- pulmonary capillary External respiration H+ + HCO3- HbH+ CO2 RBC H2 CO3 CO2 H2O HbO2 RBC O2 O2 HbCO2 pulmonary capillary alveolus plasma CO2 O2 CO2 exits blood O2 enters blood lung pulmonary artery pulmonary vein heart systemic vein tissue cells systemic artery HCO3- plasma plasma H+ + HCO3- systemic capillary systemic capillary RBC RBC H2CO3 HbH+ O2 O2 O2Hb H2O CO2 CO2 O2 HbCO2 Internal respiration tissue fluid tissue cell tissue cell tissue fluid CO2 enters blood O2 exits blood

Respiration and Human Health Biology, 9th ed, Sylvia Mader Chapter 37 Respiration and Human Health Respiratory Systems Disorders Affecting the Lungs Cystic fibrosis (CF) Defective gene results in accumulation of mucus secretions in the lungs Secretions become sticky and form plugs that interfere with breathing Treatment involves clearing mucus from airways administering mucus-thinning drugs and vigorously slapping the patient on the back