STUDY This Information Respiration Part 1 Impacts Issues

STUDY This Information Respiration Part 1

Impacts, Issues Up in Smoke § Smoking immobilizes ciliated cells and kills white blood cells that defend the respiratory system; highly addictive nicotine discourages quitting

The Nature of Respiration § All animals must supply their cells with oxygen and rid their body of carbon dioxide § Respiration • The physiological process by which an animal exchanges oxygen and carbon dioxide with its environment

Interactions with Other Organ Systems

food, water intake oxygen intake Digestive System Respiratory System nutrients, water, salts oxygen elimination of carbon dioxide Circulatory System Urinary System water, solutes elimination of food residues rapid transport to and from all living cells elimination of excess water, salts, wastes Fig. 39 -2 b, p. 682

The Basis of Gas Exchange § Respiration depends on diffusion of gaseous oxygen (O 2) and carbon dioxide (CO 2) down their concentration gradients § Gases enter and leave the internal environment across a thin, moist layer (respiratory surface) that dissolves the gases

Partial Pressure § Partial pressure • Of the total atmospheric pressure measured by a mercury barometer (760 mm Hg), O 2 contributes 21% (160 mm Hg) 760 mm Hg Fig. 39 -3, p. 682

Factors Affecting Diffusion Rates STUDY § Factors that increase diffusion of gases across a respiratory surface: • High partial pressure gradient of a gas across the respiratory surface • High surface-to-volume ratio • High ventilation rate (movement of air or water across the respiratory surface)

Respiratory Proteins STUDY § Respiratory proteins contain one or more metal ions that reversibly bind to oxygen atoms • Hemoglobin: An iron-containing respiratory protein found in vertebrate red blood cells • Myoglobin: A respiratory protein found in muscles of vertebrates and some invertebrates

Gasping for Oxygen § Rising water temperatures, slowing streams, and organic pollutants reduce the dissolved oxygen (DO) available for aquatic species

Principles of Gas Exchange § Respiration is the sum of processes that move ____ from air or water in the environment to all metabolically active ____ and move _____ from those tissues to the outside § Oxygen levels are more stable in air than in water

Principles of Gas Exchange § Respiration is the sum of processes that move oxygen from air or water in the environment to all metabolically active tissues and move carbon dioxide from those tissues to the outside § Oxygen levels are more stable in air than in water

Invertebrate Respiration STUDY § Integumentary exchange • Some invertebrates that live in aquatic or damp environments have no respiratory organs; • Gases diffuse across the skin § Gills • Filamentous respiratory organs that increase surface area for gas exchange in water § Lungs • Saclike respiratory organs with branching tubes that deliver air to a respiratory surface § Snails and slugs that spend some time on land have a lung instead of, or in addition to, gills

Snails with Lungs

Invertebrate Respiration STUDY § Tracheal system • Insects and spiders with a hard integument have branching tracheal tubes that open to the surface through spiracles (no respiratory protein required) § Book lungs • Some spiders also have thin sheets of respiratory tissue that exchange oxygen with a respiratory pigment (hemocyanin) in blood

trachea (tube inside body) spiracle (opening to body surface) STUDY Insect Tracheal System Fig. 39 -7, p. 685

air-filled space blood-filled space STUDY book lung A Spider’s Book Lung Fig. 39 -8, p. 685

Key Concepts Gas Exchange in Invertebrates § Gas exchange occurs across the body surface or gills of aquatic invertebrates § In large invertebrates on land, it occurs across a moist, internal respiratory surface or at fluid-filled tips of branching tubes that extend from the surface to internal tissues

Vertebrate Respiration § Fishes use gills to extract oxygen from water • Countercurrent flow aids exchange (blood flows through gills in opposite direction of water flow) § Amphibians exchange gases across their skin, and at respiratory surfaces of paired lungs • Larvae have external gills

Fish Gills (a) Location of the gill cover of a bony fish. gill cover Fig. 39 -9 a, p. 686

STUDY mouth open gill (b) Water is sucked into the mouth and over the gills when a fish closes its gill covers, opens its mouth, and expands its oral cavity. cover closed Fig. 39 -9 b, p. 686

mouth closed (c) The water moves out when the fish closes its mouth, opens its gill covers, and squeezes the water past its gills. STUDY gill cover open Fig. 39 -9 c, p. 686

Countercurrent Flow gill filaments one gill arch water is sucked into mouth STUDY Water exits through gill slits A A bony fish with its gill cover removed. Water flows in through the mouth, flows over the gills, then exits through gill slits. Each gill has bony gill arches to which the gill filaments attach. Fig. 39 -10 a, p. 686

STUDY gill arch respiratory surface gill filament fold with a capillary bed inside water flow direction of blood flow oxygen-poor blood oxygenated blood from deep in body back toward body B Two gill arches with filaments C Countercurrent flow of water and blood Fig. 39 -10 (b-c), p. 686

Frog Respiration A Lowering the floor of the mouth draws air inward through nostrils. STUDY B Closing nostrils and raising the floor of the mouth pushes air into lungs. C Rhythmically raising and lowering the floor of the mouth assists gas exchange. D Contracting chest muscles and raising the floor of the mouth forces air out of lungs, and the frog exhales. Fig. 39 -11, p. 687

Vertebrate Respiration § Reptiles, birds and mammals exchange gases through paired lungs, ventilated by chest muscles § Birds have the most efficient vertebrate lungs • Air sacs allow oxygen-rich air to pass respiratory surfaces on both inhalation and exhalation

Bird Respiratory System A Inhalation 1 Muscles expand chest cavity, drawing air in through nostrils. Some of the air flowing in through the trachea goes to lungs and some goes to posterior air sacs. B Exhalation 1 Anterior air sacs empty. Air from posterior air sacs moves into lungs. trachea STUDY anterior air sacs lung posterior air sacs C Inhalation 2 Air in lungs moves to anterior air sacs and is replaced by newly inhaled air. D Exhalation 2 Air in anterior air sacs moves out of the body and air from posterior sacs flows into the lungs. Fig. 39 -12, p. 687

Fig. 39 -12 (inset), p. 687

Human Respiratory System STUDY § The human respiratory system functions in gas exchange, sense of smell, voice production, body defenses, acid-base balance, and temperature regulation

Airways STUDY § Air enters through nose or mouth, flows through the pharynx (throat) and the larynx (voice box) • Vocal cords change the size of the glottis § The epiglottis protects the trachea, which branches into two bronchi, one to each lung • Cilia and mucus-secreting cells clean airways

glottis closed vocal cords glottis open glottis (closed) epiglottis tongue’s base STUDY Larynx: Vocal Cords and Glottis Fig. 39 -14, p. 689

From Airways to Alveoli STUDY § Inside each lung, bronchi branch into bronchioles that deliver air to alveoli § Alveoli are small sacs, one cell thick, where gases are exchanged with pulmonary capillaries

Muscles and Respiration STUDY § Muscle movements change the volume of the thoracic cavity during breathing § Diaphragm • A broad sheet of smooth muscle below the lungs • Separates the thoracic and abdominal cavities § Intercostal muscles • Skeletal muscles between the ribs

Functions of the Respiratory System Nasal Cavity Chamber in which air is moistened, warmed, and filtered, and in which sounds resonate Pharynx (Throat) Airway connecting nasal cavity and mouth with larynx; enhances sounds; also connects with esophagus Epiglottis Closes off larynx during swallowing Larynx (Voice Box) Airway where sound is produced; closed off during swallowing Trachea (Windpipe) Airway connecting larynx with two bronchi that lead into the lungs Oral Cavity (Mouth) Supplemental airway when breathing is labored Pleural Membrane Double-layer membrane with a fluid-filled space between layers; keeps lungs airtight and helps them stick to chest wall during breathing Intercostal Muscles At rib cage, skeletal muscles with roles in breathing. There are two sets of intercostal muscles (external and internal) Diaphragm Muscle sheet between the chest cavity and abdominal cavity with roles in breathing Lung (One of a Pair) Lobed, elastic organ of breathing; enhances gas exchange between internal environment and outside air Bronchial Tree Increasingly branched airways starting with two bronchi and ending at air sacs (alveoli) of lung tissue STUDY Fig. 39 -13 a, p. 688

bronchiole alveolar sac (sectioned) alveolar duct alveoli STUDY Fig. 39 -13 b, p. 688

alveolar sac STUDY pulmonary capillary Fig. 39 -13 c, p. 688

Cyclic Reversals in Air Pressure Gradients STUDY § Respiratory cycle • One inhalation and one exhalation § Inhalation is always active • Contraction of diaphragm and external intercostal muscles increases volume of thoracic cavity • Air pressure in alveoli drops below atmospheric pressure; air moves inward

Cyclic Reversals in Air Pressure Gradients STUDY § Exhalation is usually passive • As muscles relax, the thoracic cavity shrinks • Air pressure in the alveoli rises above atmospheric pressure, air moves out § Exhalation may be active • Contraction of abdominal muscles forces air out

The Thoracic Cavity and the Respiratory Cycle

Inward flow of air A Inhalation. Diaphragm contracts, moves down. External intercostal muscles contract, lift rib cage upward and outward. Lung volume expands. Fig. 39 -15 a, p. 690

Outward flow of air B Exhalation. Diaphragm, external intercostal muscles return to resting positions. Rib cage moves down. Lungs recoil passively. Fig. 39 -15 b, p. 690

Supplemental: First Aid for Choking § Heimlich maneuver • Upward-directed force on the diaphragm forces air out of lungs to dislodge an obstruction

Respiratory Volumes § Air in lungs is partially replaced with each breath • Lungs are never emptied of air (residual volume) § Vital capacity • Maximum volume of air the lungs can exchange § Tidal volume • Volume of air that moves in and out during a normal respiratory cycle

Respiratory Volumes

Control of Breathing § Neurons in the medulla oblongata of the brain stem are the control center for respiration • Rhythmic signals from the brain cause muscle contractions that cause air to flow into the lungs § Chemoreceptors in the medulla, carotid arteries, and aorta wall detect chemical changes in blood, and adjust breathing patterns

STIMULUS CO 2 concentration and acidity rise in the blood and cerebrospinal fluid. Respiratory Responses RESPONSE Chemoreceptors in wall of carotid arteries and aorta Respiratory center in brain stem Diaphragm, Intercostal muscles CO 2 concentration and acidity decline in the blood and cerebrospinal fluid. Tidal volume and rate of breathing change. Stepped Art Fig. 39 -18, p. 691

Gas Exchange and Transport § Gases diffuse between a pulmonary capillary and an alveolus at the respiratory membrane • Alveolar epithelium • Capillary endothelium • Fused basement membranes § O 2 and CO 2 each follow their partial pressure gradient across the membrane

The Respiratory Membrane red blood cell inside pulmonary capillary pore for air flow between adjoining alveoli air space inside alveolus a Surface view of capillaries associated with alveoli b Cutaway view of one of the alveoli and adjacent pulmonary capillaries alveolar epithelium capillary endothelium fused basement membranes of both epithelial tissues c Three components of the respiratory membrane Fig. 39 -19, p. 692

Oxygen Transport § In alveoli, partial pressure of O 2 is high; oxygen binds with hemoglobin in red blood cells to form oxyhemoglobin (Hb. O 2) § In metabolically active tissues, partial pressure of O 2 is low; Hb. O 2 releases oxygen § Myoglobin, found in some muscle tissues, is similar to hemoglobin but holds O 2 more tightly

alpha globin Structure of hemoglobin, the oxygentransporting protein of red blood cells. It consists of four globin chains, each associated with an ironcontaining heme group, colorcoded red. beta globin Hemoglobin beta globin Fig. 39 -20 a, p. 693

Myoglobin heme Myoglobin, an oxygen-storing protein in muscle cells. Its single chain associates with a heme group. Compared to hemoglobin, myoglobin has a higher affinity for oxygen, so it helps speed the transfer of oxygen from blood to muscle cells. Fig. 39 -20 b, p. 693

Carbon Dioxide Transport § Carbon dioxide is transported from metabolically active tissues to the lungs in three forms • 10% dissolved in plasma • 30% carbaminohemoglobin (Hb. CO 2) • 60% bicarbonate (HCO 3 -) § Carbonic anhydrase in red blood cells catalyzes the formation of bicarbonate CO 2 + H 2 O → H CO → HCO 2 3 3 - + H+

DRY INHALED AIR 160 0. 03 Partial Pressures for Oxygen and Carbon Dioxide Partial pressures (in mm Hg) for oxygen (pink boxes) and carbon dioxide (blue boxes) in the atmosphere, blood, and tissues. Figure It Out: What is the partial pressure of oxygen in arteries that carry blood to systemic capillary beds? pulmonary arteries 40 45 120 27 alveolar sacs 104 40 start of systemic veins MOIST EXHALED AIR pulmonary veins 100 40 start of systemic capillaries 100 40 40 45 Answer: 100 mm Hg cells of body tissues less than 40 more than 45 Stepped Art Fig. 39 -21, p. 693

The Carbon Monoxide Threat § Carbon monoxide (CO) • A colorless, odorless gas that can fill up O 2 binding sites on hemoglobin, block O 2 transport, and cause carbon monoxide poisoning § Carbon monoxide poisoning often results when fuel-burning appliance are poorly ventilated • Symptoms include nausea, headache, confusion, dizziness, and weakness

Key Concepts Gas Exchange in Vertebrates § Gills or paired lungs are gas exchange organs in most vertebrates § The efficiency of gas exchange is improved by mechanisms that cause blood and water to flow in opposite directions at gills, and by muscle contractions that move air into and out of lungs

Respiratory Diseases and Disorders § Interrupted breathing • Brain-stem damage, sleep apnea, SIDS § Potentially deadly infections • Tuberculosis, pneumonia § Chronic bronchitis and emphysema • Damage to ciliated lining of bronchioles and walls of alveoli; tobacco smoke is the main risk factor

Cigarette Smoke and Ciliated Epithelium Fig. 39 -22 a, p. 694

free surface of a mucussecreting cell free surface of a cluster of ciliated cells Fig. 39 -22 b, p. 694

Risks Associated With Smoking and Emphysema (a) From the American Cancer Society, a list of major risks incurred by smoking and the benefits of quitting. (b) Appearance of normal lung tissue in humans. (c) Appearance of lung tissues from someone who was affected by emphysema.

Key Concepts Respiratory Problems § Respiration can be disrupted by damage to respiratory centers in the brain, physical obstructions, infectious disease, and inhalation of pollutants, including cigarette smoke

High Climbers and Deep Divers § Altitude sickness • Hypoxia can result when people who live at low altitudes move suddenly to high altitudes • People who grow up at high altitudes have more alveoli and blood vessels in their lungs § Acclimatization to altitude includes adjustments in cardiac output, rate and volume of breathing • Hypoxia stimulates erythropoietin secretion

Adaptation to High Altitude § Llamas that live at high altitudes have special hemoglobin that binds oxygen more efficiently

Deep-Sea Divers § Water pressure increases with depth; human divers using compressed air risk nitrogen narcosis (disrupts neuron signaling) § Returning too quickly to the surface from a deep dive can release dangerous nitrogen bubbles into the blood stream (‘the bends”) § Without tanks, trained humans can dive to 210 meters; sperm whales can dive 2, 200 meters

Adaptations for Deep Diving § Leatherback turtles dive up to one hour • Move air to cartilage-reinforced airways • Flexible shell for compression § Four ways diving animals conserve oxygen • • Deep breathing before diving High red-cell count, large amounts of myoglobin Slowed heart rate and metabolism Conservation of energy

Deep Divers

Key Concepts Gas Exchange in Extreme Environments § At high altitudes, the human body makes shortterm and long-term adjustments to thinner air § Built-in respiratory mechanisms and specialized behaviors allow sea turtles and diving marine mammals to stay under water, at great depths, for long periods

Video Supplements

Animation: Bird respiration

Animation: Human respiratory system

Animation: Examples of respiratory surfaces

Animation: Vertebrate lungs

Animation: Bony fish respiration

Animation: Frog respiration

Animation: Respiratory cycle

Animation: Heimlich maneuver

Animation: Changes in lung volume and pressure

Animation: Partial pressure gradients

Animation: Bicarbonate buffer system

Animation: Globin and hemoglobin structure

Animation: Pressure-gradient changes during respiration

Animation: Structure of an alveolus

Animation: Vocal cords

ABC video: Blood test for lung cancer

Video: Up in smoke