chapter 22 respiration study guide

Chapter 22 • Respiratory System • Study Guide Page 1 of 7Thursday April 9, 2009BIOL2112-Chapter22-Respiration-StudyGuide01.pdfChapter 22 • Respiratory System • Study GuideAnatomy and Physiology II • BIOL 2112Chapter 22 respirationNasal bone – is relatively shortNasal cartilages determine most of the size and shape of the noseThe nostrils are called naresNasal cavityEpithelial cells secrete mucus and lysozymessecrete about a quart of mucus a day which is usually carried down the throatFolds called conchae increase surface area and enhanceSense of smellTrapping of foreign particlesWarming of cold airHumidifying incoming air and conserving moisture in outgoing airPharynx –Nasopharynx – is continuous with the posterior nasal cavityOropharynx – lies posterior to the oral cavityLaryngopharynx – lies posterior to the larynxBelow the larynx, the pharynx becomes the esophagusThe pharyngotympanic tube (Eustachian tube) enters the posterior nasalcavity. This tube helps equalize atmospheric pressure with the middle earpressure. Tubal tonsils near the tube help prevent middle ear infections.Larynx –The opening to the larynx is the glottis.The epiglottis falls over the glottis and blocks food from entering.Is for voice productionThe vocal cords are ligamentsAdam’s apple is the thyroid cartilage over the vocal cordsPitch is determined by tenseness of the vocal cordsLoudness by the force of air rushing over the vocal cordsAnd quality of voice by resonance of oral and nasal cavitiesC:\Documents and Settings\adele.cunningham\My Documents\APII spring 09\lecturesand study guides APII spring 09\study guides APII spring 09\chapter 22 respiration studyguide.docSave date: Monday, April 13, 2009 10:10:00 AM

Chapter 22 • Respiratory System • Study Guide Page 2 of 7Thursday April 9, 2009BIOL2112-Chapter22-Respiration-StudyGuide01.pdfTracheaIs lined with epithelial tissue cells that secrete mucusAnd ciliated cells that move mucus and debris toward the pharynx where it isswallowed or coughed outSmoking inhibits/destroys ciliaU-shaped cartilages keep the airway openMuscles at the open end of the U, trachealis muscles, allow you todecrease the diameter of the trachea and propel air out forcefullyHeimlich maneuverEach thrust is intended to move the diaphragm and create an artificial coughthat will expel the objectHeimlich maneuver was invented because sometimes blows to the back make anobstruction worseGross anatomy of lungsThe left lung is slightly smaller than the right and wraps around the heartThe left lung has two lobesThe right lung has three lobesMost of lung tissue is elastic connective tissueEach lung is divided into segments separated by connective tissue - about 10 inthe right lung and 8 or 9 in the left lung.Each segment has its own artery, vein, and bronchusPulmonary disease is frequently confined to a single segmentSurgery can remove just the diseased segment without affecting other segments.Pleurae – serous membranes called pleurae line the lungs. Serous membranesare double-walled with fluid between the walls. This fluid allows the lungs to expandeasily. Infection within the pleurae is called pleurisy.Pleurae form a seal with the thoracic wall so that lungs cling tightly to the thorax wallas it changes volume.This seal is disrupted when air enters the pleural cavity due to trauma. Airbetween the two layers of the pleurae is called pneumothorax and causes lungcollapse.C:\Documents and Settings\adele.cunningham\My Documents\APII spring 09\lecturesand study guides APII spring 09\study guides APII spring 09\chapter 22 respiration studyguide.docSave date: Monday, April 13, 2009 10:10:00 AM

Chapter 22 • Respiratory System • Study Guide Page 3 of 7Thursday April 9, 2009BIOL2112-Chapter22-Respiration-StudyGuide01.pdfBronchi – the trachea divides into two bronchi. (Figure 22.7) The right bronchus isshorter and straighter and foreign objects are more likely to lodge there.There are about 23 orders of branching from bronchi to the smallestbronchioles. This conducting network in the lungs is called the bronchial tree(Figure 22.11).Trachea and largest bronchi are reinforced with U-shaped cartilages that keepthese large airways openSomewhat smaller bronchi are reinforced with plates of cartilageBronchioles are reinforced with smooth muscleAll have elastic fibersMicroscopic anatomyAlveoli – thin-walled sacs where gas exchange takes place. (Figure 22.9 a, b, c)Surface tension – water molecules adhere to each other and to the sides of anycontainerIf the fluids lining alveoli were only water, the alveoli would collapse betweenbreathsSurfactant made in the alveoli reduces the surface tension of water and keepsalveoli from collapsing as gases are exchanged with surrounding capillaries.Premature newborns do not have enough surfactant and must reinflate alveolibetween breaths.Mechanics of breathingInhalationMuscles involved in inhalation – diaphragm – contracts and flattensExternal intercostal muscles – ribs are elevated and sternum flares outwardThe rib cage is wider inferiorly so lifting it slightly increases thoracic volumeTo take a deeper breath – sternocleidomastoid and the pectoralis major muscles bothlift the rib cageLungs cling to the thoracic wallLungs are very elastic and expand with the thoracic wallInhalation requires energy, but exhalation is passive (except during forced expiration)Exhalation is based on relaxation of the muscles used in inhalation and does not requireenergy. The lungs are high in elastic tissue and rebound after being stretched.C:\Documents and Settings\adele.cunningham\My Documents\APII spring 09\lecturesand study guides APII spring 09\study guides APII spring 09\chapter 22 respiration studyguide.docSave date: Monday, April 13, 2009 10:10:00 AM

Chapter 22 • Respiratory System • Study Guide Page 4 of 7Thursday April 9, 2009BIOL2112-Chapter22-Respiration-StudyGuide01.pdfMeasurement of lung functionVital capacity – is a measure of lung function (not actual volumes).Tidal volume – the volume inhaled and exhaled at restVC = TV+IRV+ERV. The maximal amount that can be exhaled after a maximuminhalation.Inspiratory reserve volume is the amount of air that can be forcibly inhaled after anormal inhalation.Expiratory reserve volume is the amount of air that can be forcibly exhaled after anormal exhalation.In a lung function test, the patient is often tested for vital capacity. The patient does amaximum inhalation followed by a maximal exhalation. The volume of maximalinhalation is normally more than the volume of maximal exhalation. This is because acertain amount of air remains in the lungs to keep them inflated. This air that remainsin the lungs is the residual volume.General principles of gas flowGases diffuse – from high to low concentrationsAnd from areas of higher pressure to areas of lower pressureFor gases, if you increase volume, you decrease pressureIncreasing the volume of the thorax when you inhale decreases the pressure in thethorax and air rushes into the lungs because there is less air pressure in the lungs thanin the air. For gases pressure is inversely proportional to volume.Partial pressure is a way of describing the proportions of gases in a mixtureGases are measured in mmHg. The gases in the atmosphere can raise a column ofmercury 760mm so one atmosphere is 760mmHg. In a mixture of gases, the partialpressure of a gas, for example oxygen, is the total pressure of the mixture multipliedby the percent oxygen.Air is only about 20% oxygen, so the partial pressure of oxygen –pO 2 in theatmosphere is 760mmHg * 20%.Gases will diffuse into a liquid in proportion to their partial pressure (concentration),moving from high concentrations to lower concentrations. The amount of gas that willdiffuse is also affected by the solubility of the gas.Partial pressure of oxygen –Oxygen diffuses from a partial pressure of 100mmHg at the lungsTo a partial pressure of 40mmHg at the tissuesPartial pressure of carbon dioxide –Carbon dioxide diffuses from a partial pressure of 45mmHg at the tissues toa partial pressure of 40mmHg at lungsC:\Documents and Settings\adele.cunningham\My Documents\APII spring 09\lecturesand study guides APII spring 09\study guides APII spring 09\chapter 22 respiration studyguide.docSave date: Monday, April 13, 2009 10:10:00 AM

Chapter 22 • Respiratory System • Study Guide Page 5 of 7Thursday April 9, 2009BIOL2112-Chapter22-Respiration-StudyGuide01.pdfSo oxygen diffuses down a much steeper concentration gradient (difference inconcentration), but it is only about 1/20 th as soluble as carbon dioxide so about equalamounts of oxygen and carbon dioxide pass through the alveoli of the lungs.Hyperbaric chambers make it possible to deliver more oxygen to tissues than wouldnormally diffuse from the alveoli. These chambers contain oxygen at about 2.5 timesatmospheric pressure so oxygen diffuses very quickly from the lungs. Hyperbarictreatments were originally to treat nitrogen toxicity from diving, but they have beenfound to be beneficial for healing wounds, especially infected wounds involvinganaerobic bacteria. They are also used to treat carbon monoxide poisoning.Structure of hemoglobinHemoglobin has four protein chains called globins. Each globin surrounds aheme group containing iron.Globins carry carbon dioxideIrons of each heme carry oxygenOnly a small amount of oxygen will dissolve in blood plasma.The heart would have to work many times harder to provide enough oxygen ifhemoglobin didn’t carry oxygen.In the lungs hemoglobin is 100% saturated (all hemoglobins carrying 4 oxygens)Oxygen is unloaded to tissues, but hemoglobin is still about 70% saturated (about 70%of hemoglobins carrying 4 oxygens). This 70% saturation of venous blood is the venousreserve.If oxygen content in tissues falls below 40mmHg, hemoglobin loses oxygenvery quickly in response to small decreases in oxygen in the tissues.In the red blood cellsA single hemoglobin molecule in a red blood cell tends to carry either oxygen or carbondioxide because binding by one inhibits binding by the other.Transport of carbon dioxideCO 2 +H 2 O -> H 2 CO 3 -> H + + HCO 3–H 2 CO 3 is carbonic acid. It dissociates into H + + HCO 3–Most carbon dioxide in the blood is carried as bicarbonate (HCO 3 – ) that is formed inthe red blood cells. At the lungs the bicarbonate is converted back to carbon dioxideand released.When the body needs more oxygenHemoglobin affinity for oxygen decreasesBreathing depth and rate increaseC:\Documents and Settings\adele.cunningham\My Documents\APII spring 09\lecturesand study guides APII spring 09\study guides APII spring 09\chapter 22 respiration studyguide.docSave date: Monday, April 13, 2009 10:10:00 AM

Chapter 22 • Respiratory System • Study Guide Page 6 of 7Thursday April 9, 2009BIOL2112-Chapter22-Respiration-StudyGuide01.pdfControl of breathing depth and rateInhalation and exhalation are under control of an area of the medulla oblongata calledthe ventral respiratory group. Complete inhibition of ventral respiratory group byalcohol or morphine can stop breathing.Chemoreceptors in aortic arch and carotids and chemoreceptors in the brain in themedullarespond to changes in pH in cerebrospinal fluid.When pH falls,phrenic nerve innervates the diaphragm to increase breathing rate.Normally, Carbon dioxide is the most powerful stimulant for breathingbecause it lowers pH in the brain. Remember carbonic dioxide will form carbonic acid inthe erythrocytes. Low carbon dioxide levels will depress breathing.Metabolic factorsalso can lower pH and increase breathing depth and rateFatty acid metabolism - especially in diabetes mellitusLactic acid from exerciseFactors that cause hemoglobin to release oxygen (decrease hemoglobin affinity foroxygen) are by-products of metabolically active cellsIncrease of carbon dioxide in the bloodLower pH in the blood (from increased carbon dioxide, fatty acid metabolism,or lactic acid as above)Heat – heat is released when you exerciseIncreases in BPG from glycolysis – the anaerobic process that makes ATP fromglucose. Glycolysis increases during exercise.The almost instantaneous change to a faster breathing rate that occurs when youbegin exercise does not seem to be activated metabolicallyDuring exercise oxygen and carbon dioxide levels remain relatively constantThe change in breathing rate may be stimulated by proprioceptors inmuscles. Proprioceptors detect muscle stretch.Abnormal lung functionAny condition that decreases lung elasticity (for instance scarring of the lung) willinhibit breathingC:\Documents and Settings\adele.cunningham\My Documents\APII spring 09\lecturesand study guides APII spring 09\study guides APII spring 09\chapter 22 respiration studyguide.docSave date: Monday, April 13, 2009 10:10:00 AM

Chapter 22 • Respiratory System • Study Guide Page 7 of 7Thursday April 9, 2009BIOL2112-Chapter22-Respiration-StudyGuide01.pdfCOPDChronic obstructive pulmonary disease characteristics80% are smokersHypoventilation – poor gas exchangeTypes of COPDEmphysemaLoss of lung elasticityAlveoli walls breakBronchioles open during inspiration and collapse on exhalationTremendous effort to breathe 15-20% of total energy expendedtraditionally associated with pink puffers – patients withlow body weight from extra effort to breathe, but nearlynormal levels of oxygen and carbon dioxideChronic bronchitisExcessive mucus in lower respiratory passagesInflammation and fibrosisBacterial infections in stagnant mucusTraditionally associated with blue bloaters – patients who areoverweight and cyanotic. Chronic high carbon dioxide meansconstricted pulmonary arterioles and stress on right heart-COPD patients are treated with oxygenDanger of giving too much oxygenWith high levels of oxygen, carbon dioxide is displaced fromhemoglobinAlveoli damaged by disease are not able to release this excessAnd pH in the blood decreases to dangerously acid levelsLung cancer90% are smokersSmoking paralyzes cilia leaving lungs vulnerable to irritantsExposes lungs to carcinogensADHSmall cell carcinoma –Sometimes forms ectopic sites of production of the hormones ACTH andACTH – Adrenocorticotropic hormone – increases especiallyglucocorticoids from the adrenalsADH – antidiuretic hormone – increases return of water to thebloodstream at the kidneysC:\Documents and Settings\adele.cunningham\My Documents\APII spring 09\lecturesand study guides APII spring 09\study guides APII spring 09\chapter 22 respiration studyguide.docSave date: Monday, April 13, 2009 10:10:00 AM