Chapter 22: Respiratory System

25 July 2022
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What does 'lung compliance' refer to?
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The measure of a change in lung volume that occurs with a change in transpulmonary pressure. It is determined by destinsibility of the lung tissue and aveolar surface tension.
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What determines lung compliance?
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It is determined by destinsibility of the lung tissue and aveolar surface tension.
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What determines the volume of your voice?
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The force of the air moving over the vocal folds.
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What type epithelium composes the type I cells?
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Simple squamous epithelium
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What is the function of type I cells?
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Forms the alveolar wall along with the thin basement membrane(fused with capillary basement membrane) it creates the respiratory membrane allowing gas exchange with the surrounding web-like network of capillaries.
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What type epithelium composes the type II cells?
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Cuboidal epithelium
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What is the function of type II cells?
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Secretes surfactant and antimicrobial proteins.
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Boyles Law
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At constant temperature the pressure of a gas varies inversely with its volume. Gas always fills its container, but the larger the container the lesser the pressure and the smaller the container the greater the pressure of the molecules.
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Dalton's Law
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The total pressure exerted by a mixture of gases is the sum of the pressures exerted independently by each gas in the mixture. The pressure exerted by each gas- its partial pressure- is directly proportional to the percentage of gas in the gas mixture.
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Henry's Law
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When a gas is in contact with a liquid, the gas will dissolve in the liquid in proportion to its partial pressure. The greater the concentration of a particular gas, the more and faster it will go into solution in the liquid.
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Relate air movement into or out of the lungs to atmospheric pressure.
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When the atmospheric pressure is greater than the pressure inside the lungs, air rushes in until it is equalized. When the pressure inside the lungs becomes greater than the atmospheric pressure, air rushes out.
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Intrapulmonary pressure
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the pressure in the alveoli
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Expiration depends on 2 factors. What are they?
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Lung elasticity & muscle contraction
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The trachea is very flexible. What keeps it open?
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Its c-shaped hyaline cartilage rings.
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Surfactant
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A dish liquid like substance that coats and reduces the surface tension of the alveoli, preventing collapse
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Valsalva's maneuver
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A collective event involving the glottis closing preventing expiration during abdominal straining causing a rise in intra-abdominal pressure. Occurs during bowel movement and heavy-lifting.
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Bohr effect
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CO2 enters blood from tissues causing O2 to dissociate from Hb
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Tidal Volume (TV)
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The amount of air inhaled/exhaled with each breath during normal breathing
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Vital Capacity (VC)
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Maximum amount of air that can be expired after a maximum inspiratory effort VC=TV + IRV + ERV
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Inspiratory Capacity (IC)
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Maximum amount of air that can be inspired after normal expiration
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Expiratory Reserve Volume (ERV)
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Amount of air that can be forecefull exhaled after a normal tidal volume exhalation
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Inspiratory Reserve Volume (IRV)
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Amount of air that can be forcefully inhaled after a normal tidal volume
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Residual Volume (RV)
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Amount of air remaining in the lungs after a forced exhalation
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For efficient gas exchange. what is the optimal thickness of the respiratory membrane?
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0.5 to 1 micrometer
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In a healthy person, what is the most powerful stimulus for breathing?
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The need to rid itself of CO2
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Nerve impulses that stimulate inspiration originate in which respiratory center?
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Medullary respiratory centers of the medulla oblongata.
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What 2 factors prevent the lungs from collapsing?
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Surfactant and the residual volume that remains in the lungs.
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What percentage of molecular O2 is carried by the RBC's compared to the percentage carried in the plasma?
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02 98.5% bound to Hb & 1.5% in plasma.
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What percentage of molecular CO2 is carried by the RBC's compared to the percentage carried in the plasma?
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CO2 7-10% dissolved in plasma & 20% bound to Hb (remaining 70% transported as bicarbonate ions in plasma)
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What determines the direction of respiratory gas movement?
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The partial pressure gradient.
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Adenocarcinoma
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(40% of lung cancer cases) originates in peripheral lung areas as solitary nodules that develop from bronchial glands and alveolar cells
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Squamous cell carcinoma
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(25-30% lung cancer cases) arises in the epithelium of the bronchi or larger subdivisions and forms masses that cavitate (hollow out) and bleed
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At what developmental stage could a baby born prematurely breathe on its own?
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By 28 weeks
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Small cell carcinoma
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(20% lung cancer cases) round, lymphocyte-sized cells that originate in the main bronchi and grow aggressively in small grapelike clusters within the medistinum. Metastasis is rapid. Some may cause additional problems because they produce certain hormones such as ACTH or ADH resulting in Cushing's or Syndrome of Inappropriate ADH secretion (SIADH) respectively
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Know the divisions of the conducting zones (the bronchial tree).
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Trachea, primary (right & left main) bronchi, lobar (secondary) bronchi, segmental (tertiary) bronchi, bronchioles, and terminal bronchioles.
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Where is cartilage present in the bronchial tree; where does it disappear?
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Cartilage is present as rings in the trachea and then becomes irregular plates of cartilage in the bronchi, it disappears in the bronchioles.
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How does cross-sectional diameter of the bronchial tree effect resistance to air flow?
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As diameter decreases air resistance increases but the number of passageways becomes greater.
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How is respiratory exchange accomplished during fetal development?
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Through the placenta
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What is hypoxia? What are some possible causes?
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Lack of oxygen in the tissues. Causes may be: Carbon monoxide poisoning anemia- two few RBCs to deliver O2 or not enough Hb Ishemic (stagnant) hypoxia- circulation blocked from CHF, emboli, or thrombi Histotoxic hypoxia- cells are unable to use O2, caused by metabolic poisons such as cyanide Hypoxemic hypoxia- reduced arterial P O2 abnormal ventilation-perfusion coupling, pulmonary diseases that impair ventilation, and breathing scant amounts of O2
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What is the effect of rising CO2 levels in the blood?
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It lowers the pH (increases H+)
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Where are the respiratory control centers located?
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In the brainstem, the control center of the medulla oblongata is the medullary resp ctr, the control center of the pons is the pontine resp ctr.
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By what mechanism/process is gas exchange accomplished in the lungs and at all cell membranes?
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The pressure gradient.
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Know when the diaphragm contracts or relaxes (and the same for intercostal muscles) during breathing
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During inspiration intercostals contract and the diaphragm contracts and descends. During expiration the intercostals relax and the diaphragm relaxes and moves back to original position.
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Hemoglobin
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Protein on RBCs that transports/binds to O2 and CO2
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Carbaminohemoglobin
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Carbon dioxide that is chemically bound to hemoglobin
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Bicarbonate
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CO2 ions transported in plasma; HCO3-
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Carbonic Acid
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Carbon dioxide and water H2CO3
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What is the function of the pleura?
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Lines the lungs and the thoracic cavity, protects lungs, and produces a lubricating fluid to reduce friction during inspiration.
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Review the structure of the right lung compared to the left lung. Know the structures found on each.
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Right lung has 3 lobes (superior, middle, & inferior) divided by horizontal fissure b/t superior & middle and oblique fissure b/t middle & inferior Left lung has 2 lobes divided by oblique fissure Left lung has a concavity on the medial surface known as the cardiac notch to allow space for the heart to fit
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Where is the greatest surface area for gas exchange found
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In the alveoli
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What is the composition of the respiratory membrane?
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The fused basement membrane of the capillary walls and alveolar walls.
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What are the respiratory functions of the nose?
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Provides and airway for respiration, moistens and warms entering air, and filters and cleans inspired air.
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Describe the respiratory rate of a newborn
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Newborn infants have the fastest respiratory rate at 40-80 breaths per minute.
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Regarding respiration, what is the function of the: pons, DRG, PRG?
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The pons fine tunes the actions of the VRG to smooth the transition between inspiration and respiration as well as during exercise, sleep, and speech. DRG integrates peripheral sensory input and modifies the rhythm set by the VRG. VRG generate rhythm, and the output drives respiration due to a cycle of inspiration and expiration stimulation and inhibition.
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What 2 factors are responsible for holding the lungs to the thorax wall?
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The elasticity of the chest wall and the pleural fluid between the pleura.
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What factors promote oxygen binding (loading) to hemoglobin?
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Decrease in temperature, blood pH, P CO2,and amount of BPG in the blood.
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What factors promote oxygen dissociation (unloading) from hemoglobin?
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Increase in temperature, blood pH, P CO2,and amount of BPG in the blood.
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The cilia and mucus lining the nose has what function?
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To filter the air we breath by trapping (mucus) and propelling debris (cilia) toward the stomach to be digested
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What is the relationship between the amount of alveolar surface tension and the amount of muscle action needed to keep the lungs at the thorax wall?
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The greater one alveolar surface tension, the greater the muscle action needed to keep the lungs at the thorax wall.
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Which respiratory disorder results from destruction of the walls of the alveoli?
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Emphysema
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Which factors influence hemoglobin saturation?
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Partial pressure(availability) of O2, temperature, blood pH, Partial pressure of CO2, and the amount of BPG in the blood.
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Hemoglobin can bind up to ____ (how many) molecules of O2.
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4
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Normally, how does intrapleural pressure compare to the pressure in the alveoli.
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It is normally about 4mm Hg less than the pressure in the alveoli, that is it is always negative to alveolar pressure.
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Atelectasis
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Lung collapse
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Dyspnea
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Difficult or labored breathing; air hunger
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What is the effect of smoking on the cilia of the respiratory tract?
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It inhibits and ultimately destroys the cilia
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How do pH, temperature and BPG affect hemoglobin loading and unloading O2?
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An increase in these factors promotes unloading, a decrease in these factors promotes loading.