Understanding the Structure and Function of the Respiratory
School
Northeast Wisconsin Technical College**We aren't endorsed by this school
Course
SCIENCE 83667
Subject
Biology
Date
Dec 10, 2024
Pages
12
Uploaded by bobbiechoffman
Answer Key: Structure & Function of the Respiratory System1.Name the lobes of the right lung: right upper (superior) lobe, right middle lobe, and right lower (inferior) lobe.2.Name the lobes of the left lung: left upper (superior) lobe and left lower (inferior) lobe.3.Which lobes are separated by the fissures listed here?a.Horizontal fissure: RUL from RMLb.Right oblique fissure: RUL and RML from the RLLc.Left oblique fissure: LUL from LLL4.The parietal pleura lines the inside of the ribcage and the visceral pleura lines the surface of the lungs. The function of the pleura is to reduce friction as the lungs move. 5.What is the function of the negative pressure between the two layers of the pleura (intrapleural pressure)? It helps prevent lung collapse.6.What is the function of the conducting zone? Its function is to provide passageways for air to reach the respiratory zone.7.Name the structures of the conducting zone: Nose, Pharynx, Larynx, Trachea, Mainstem (primary) bronchi, lobar bronchi, 23 more generations of airway branching 8.What are the last structures of the conducting zone? the terminal bronchioles.9.The name given to the 25 generations of airway branching is the tracheobronchial tree. The trachea is generation 0, the mainstem (primary) bronchi are generation 1, and the terminal bronchioles are generation 25.10.What is the definition of a bronchiole? It is an airway whose diameter is < 1mm.11.What is the function of the two “ribbons” of smooth muscle that wrap around small airways? They control airway diameter.12.What is the effect of the sympathetic nervous system on bronchiole smooth muscle? It relaxes the bronchiole smooth muscles thereby allowing the airways to dilate.13.What is the effect of the parasympathetic nervous system on bronchiole smooth muscle? It contracts the bronchiole smooth muscles thereby causing the airways to constrict.14.What is the function of the respiratory zone? It allows gas exchange between the lungs and the pulmonary capillaries.
15.List the four structures of the respiratory zone: respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.16.Are the alveoli surrounded by smooth muscle? No. They are surrounded by the pulmonary capillaries and the elastic fibers.17.What is the function of the elastic fibers that surround the alveoli? They limit expansion of the alveolus (to prevent tearing) and they help with recoil during exhalation.18.What is the function of surfactant? It reduces surface tension to help prevent lung collapse.19.Structure of the Alveoli Matching:A.Alveolar macrophagesB.Alveolar poresC.Type I cellsD.Type II cells___C____ simple squamous epithelium; for gas exchange___D____ surfactant production___B____ equalize pressure; alternative route for air flow___A____ phagocytosis of cellular debris and pathogens20.What two structures fuse together to form the alveolar-capillary membrane?The wall of the alveolar Type I cell and the wall of the pulmonary capillary fuse together to form the alveolar-capillary membrane. 21.Functions of the Conducting Zone Structures Matching:a.Arytenoid cartilagesb.Epiglottisc.False vocal cordsd.Larynxe.Nasal conchaef.Pharynxg.True vocal cords___e____ create air turbulence; increase the surface area for warming, humidifying, and filtering inhaled air___g____ ligaments that vibrate to produce sound as we exhale___c____ ligaments that help close the glottis during swallowing___a____ anchor vocal cords___b____ “Guardian of the Airways”; closes during swallowing___d____ routes food & air into separate channels; voice production
___f____ passageway for air and for food and drinkAnswer Key: The Respiratory Zone1.List the four structures that are part of the respiratory zone:a.Respiratory bronchiolesb.Alveolar ductsc.Alveolar sacsd.Alveoli 2.What is the function of the respiratory zone?The function of the respiratory zone is gas exchange3.Match the following respiratory zone structures to their functions:a.Bronchial smooth muscleb.Elastic fibersc.Pulmonary capillaries___c____ gas exchange___a____ controls airway diameter___b____ limits expansion of the alveolus and helps with recoil4.Match the following alveolar structures to their functions or structure:a.Type I cellsb.Type II cellsc.Alveolar poresd.Alveolar macrophages___c____ equalizes pressure between neighboring alveoli___a____ gas exchange___d____ phagocytosis of pathogens and cellular debris___c____ provide an alternative route for the flow of air___b____ produce surfactant
5.Surfactantis a compound that is produced by the alveolar Type IIcells. It lines the internal surface of the alveoliand reduces surface tension thereby reducing the possibility of lung collapse. Production of this compound begins at about 24weeks gestation however sufficient quantities are not produced until about 34weeks gestation. Therefore, premature babies usually have significant difficulty breathing, a condition known as infant respriatorydistress syndrome.6.Gas exchange in the lungs occurs across the alveolar-capillarymembrane. This membrane is made of the plasma membranes of the alveolar Type Icells, and the pulmonary capillary. The plasma membranes are fusedtogether.
Answer Key: Gas ExchangeDefine the following terms:1.Ventilation: moving air into and out of the lungs2.Respiration: gas exchange3.Gas exchange: the movement of O2and CO2in opposite directions across a membrane. Gas exchange occurs in the lungs between the alveoli and the pulmonary capillaries – this is where the blood becomes oxygenated and CO2is removed from the blood and exhaled. Gas exchange also occurs everywhere else in the body – this is where oxygenated blood gives up O2to the cellsof the brain, liver, etc. and transports the CO2these cells produce to the lungs to get rid of it.4.External respiration: gas exchange at the lungs5.Internal respiration: gas exchange everywhere else6.The transport mechanism used for gas exchange is simplediffusion. Is this mechanism passiveor activetransport? Active transport requires ATP and passive transport requires a gradient. The driving force behind gas exchange is a partial pressure gradient.7.A gradient is a difference in concentration or pressure between two adjacent areas (ex. betweenthe alveolus and the pulmonary capillary). When a compound moves across a membrane such as the alveolar-capillary membrane due to a gradient the compound will move from the region of higherconcentration or pressure to a region of lowerconcentration or pressure. In other words, compounds move downtheir gradient. Movement continues until equilibriumis reached.
8.Dalton’s Law of Partial Pressure states that “The total pressure exerted by a mixture of gases is equal to the sum of the pressures exerted by each gas in the mixture”. This means that each gas in a mixture of gases creates partof the total pressure. Air is a mixture of gases containing about 21% O2and 79% N2.9.The pvO2of blood entering the pulmonary capillary for gas exchange = 40mmHg. The pAO2in the alveolus of the lung = 100mmHg. Is there a gradient? Yes/No. Which way does O2move? from the blood to the alveolusor from the alveolus to the blood. By the time the blood leaves the pulmonary capillary the paO2= 100mmHg. 10.The pvCO2of blood entering the pulmonary capillary for gas exchange = 45mmHg. The pACO2inthe alveolus of the lung = 40mmHg. Is there a gradient? Yes/No. Which way does CO2 move? from the blood to the alveolusor from the alveolus to the blood. By the time the blood leaves the pulmonary capillary the paCO2= 40mmHg.
Answer Key: Transport of the Respiratory Gases in the Blood & Hypoxia1.Oxygen is transport by two different mechanisms in the blood. About 1.5% of the oxygen is simply dissolvedin the plasma. The other 98.5% is transported on the Fe++ions on the hemoglobinmolecule.2.Carbon dioxide is transported by three different mechanisms. About 10% of the carbon dioxide is dissolved in the plasma. 20% of the carbon dioxide is bound to the hemoglobinmolecule. 70% of the carbon dioxide enters the red blood cellwhere it reacts with water. The red blood cell produces an enzyme called carbonic anhydrasewhich speeds up the reaction between CO2 and H2O. Initially this reaction produces a weak acid called carbonicacid. This acid dissociates into a hydrogenion, and a bicarbonateion. The hydrogenion is buffered by the hemoglobinmolecule, and the bicarbonateion leaves the red blood cell and enters the plasma. Once in the plasma the bicarbonateion buffers hydrogenions from metabolic acids.3.Matching: Match the type of hypoxia to the statements below:a.Hypoxemic hypoxiab.Anemic hypoxiac.Ischemic hypoxiad.Histotoxic hypoxia____b___ due to too few normal RBC’s____c___ heart failure____a___ caused by COPD____a___ the type of hypoxia a mountain climber sometimes experiences____d___ cells cannot utilize O2
____b___ type of hypoxia that can occur with sickle cell anemia____d___ type of hypoxia created by the release of cyanide gas in Hitler’s gas chambers4.Carbon monoxide (CO) poisoning is the leading cause of death during fires. It is easy to mistake the early warning signs of CO poisoning because they mimic the flu. Two early warning signs of CO poisoning are nauseaand headache. Soon after the signs progress to dizziness, breathlessness,collapse, and loss of consciousness. 5.The reason CO poisoning can be deadly is that CO successfully competes with oxygenfor bindingsite on the Fe++ions on the hemoglobinmolecules. The affinity of the hemoglobin molecule for carbon monoxide is 210times higher than its affinity for oxygen. Therefore, during CO poisoning hemoglobinmolecules becomes loaded with carbon monoxide rather than oxygen, and the victim is extremely hypoxic. 6.The classic sign of hypoxia is a bluish-gray coloring of the mucosa and nailbeds called cyanosis. This sign occurs when less than 75% of the hemoglobinis loaded. However, with CO poisoning cyanosisdoes not occur because the hemoglobin is fully loaded – unfortunately it is loaded with carbon monoxideinstead of oxygen. The visual sign we see instead is an abnormal cherry redcoloring to the skin.
Answer Key: Mechanics of Breathing & Regulation of Breathing Mechanics of Breathing - Inhalation:Air flows into and out of the lungs when a pressuregradient is present. In order for inhalation to occur intrapulmonarypressure must be lower than atmospheric pressure. We can easily alter intrapulmonarypressure, but we cannot change atmosphericpressure.Boyle’s Law states that pressureand volumeare inversely related. In other words, to lower the intrapulmonary pressure, we must increase the lung volume.Increasing the lung volume requires contraction of the breathing muscles. The primary muscles of inhalation are the diaphragmand the external intercostalmuscles. The diaphragmflattens during contraction pulling the lungs inferior. This action increases lung volume. The external intercostalmuscles pull the ribcage up and out, thereby pulling the lungs up and out. This action also increases lung volume. The reason the lungs move with the diaphragm and the ribcage is because a serous membrane called the pleuraconnects them.Again, Boyle’s Law states that pressureand volumeare inversely related. Therefore, during inhalation, as soon as the lung volume increasesthe intrapulmonary pressure decreases. When intrapulmonarypressure is less than atmosphericpressure a gradient exists and air will flow intothe lungs.Mechanics of Breathing - Exhalation:Passive exhalation requires the relaxation of the diaphragmand the external intercostalmuscles. Relaxation of these muscles causes lung volume to decrease, thereby causing intrapulmonary pressure to increase. Air flows out of the lungs as soon as intrapulmonarypressure is greater than atmosphericpressure.Forced exhalation requires the contraction of the abdominalmuscles and the internal intercostal muscles. Contraction of the abdominalmuscles causes the diaphragm to move up, and contraction of the internal intercostal muscles cause the ribcage to move down and in. The overall result is that lung volume decreasesquickly and pressure within the lungs increasesdramatically. As soon as intrapulmonarypressure is greater than atmosphericpressure, air will flow outof the lungs.
Regulation 0f Breathing: Matchinga.Carbon dioxide b.Central chemoreceptorsc.Hering-Breuer reflexd.Medulla oblongatae.Peripheral chemoreceptorsf.Pons___e____ found in the aortic arch and carotid arteries___f____ modifies the activity of the medulla oblongata___b____ responds to hydrogen ions from CO2, but no other acid___c____ occurs during inhalation when alveoli reach a critical level of stretch___a____ our primary stimulus to breathe___d____ stimulates the contraction of the diaphragm and the external intercostals___e____ stimulated by hydrogen ions from any acid___b____ located in the brainstem___a____ the only acid capable of crossing the blood-brain barrier and stimulating the central chemoreceptors
Answer Key: Lung Volumes and CapacitiesExpiratory reserve volume (ERV)Inspiratory reserve volume (IVR)Residual volume (RV)Tidal volume (TV)Total lung capacity (TLC)Vital capacity (VC)___VC____ the amount of air that can be exhaled after a maximal inhalation___RV____ the amount of air left in the lungs after a maximal exhalation___ERV____ the amount of air that can be exhaled after a resting exhalation___TV____ the amount of air moving into and out of the lungs during resting breathing___IRV____ the amount of air that can be inhaled after a resting inhalation___TLC____ the maximum amount of air the lungs can hold
Answer Key: Control of Breathing1.Our primary stimulus to breathe is ↑carbon dioxide. Secondary stimuli include low oxygenlevels and low pH(also known as acidosis).2.The part of the brain that directly controls breathing is the medulla oblongata. This part of the brain controls breathing by stimulating the contraction of the diaphragmand external intercostals.3.During inhalation as the lungs expand to a critical volume stretchreceptors in the lung tissue arestimulated. This triggers a reflex known as the Hering-Breuerreflex which prevents overinflationof the lungs.4.Determine the location of the following receptors that monitor breathing. Describe what the receptors respond to and how stimulating these receptors alters breathing to restore homeostasis:a.Central chemoreceptors: Central chemoreceptors are found in the medulla oblongata (brainstem). They respond to hydrogen ions onlyfrom carbon dioxide and no other acid. This is because carbon dioxide is the only acid that can cross the blood-brain barrier. The central chemoreceptors are stimulated by high levels of hydrogen ions (from high levels of CO2) and they respond by increasing the rate and depth of breathing which gets rid of the excess CO2.b.Peripheral chemoreceptors: Peripheral chemoreceptors are found in the aortic arch and the carotid arteries. They respond to high levels of hydrogen ions from any acid. They can also be stimulated by low oxygen levels. The peripheral chemoreceptors respond tohigh hydrogen ion levels and low oxygen levels by increasing the rate and depth of breathing which gets rid of excess CO2 and increases O2 levels.