Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
APHY 102 Exam 3
The Respiratory System
| Question | Answer |
|---|---|
| what is the difference between ventilation and respiration? | ventilation moves air, while respiration uses it |
| what 4 distinct processes must happen in the respiratory system? | pulmonary ventilation, external respiration, transport (job of the cardiovascular system), and internal respiration |
| what is pulmonary ventilation? | moving air into and out of the lungs |
| what is external respiration? | gas exchange between the lungs and the blood |
| what is internal respiration? | gas exchange between systemic blood vessels and tissues |
| what does transport refer to? | the transport of oxygen and CO2 between the lungs and tissues |
| what structure in the respiratory system comes vertically between the pharynx and the trachea? | larynx |
| true or false, the respiratory system consists of the respiratory and conducting zones | true |
| what is the respiratory zone? | site of gas exchange and consists of respiratory bronchioles, alveolar ducts, and alveoli (take note, an alveolus is also the name of bony tooth socket in the mandible or maxilla) |
| what is the conducting zone? | conduits (tubes) for air to reach the sites of gas exchange: includes all other respiratory structures (e.g. nose, nasal cavity, pharynx, trachea, bronchi) |
| among the following, be sure to know which are in the respiratory zone and which are in the conducting zone | respiratory bronchioles, alveolar ducts, alveoli; nose, nasal cavity, pharynx, trachea, bronchi |
| what is the only externally visible part of the respiratory system (according to the powerpoint)? | the nose |
| how does the nose function? (5 things) | provides airway for respiration, moistens and warms the entering air, filters inspired air and cleans it of foreign matter, serves as a speech resonance chamber, and houses olfactory receptors (cranial nerve 1) |
| how many regions is the nose divided into? | 2: the external nose and internal nasal cavity |
| what are the names of the parts of the external nose? | root, bridge, dorsum nasi, apex |
| know visually what the philtrum is | the shallow vertical groove inferior to the apex of the nose (above the cupid's bow of the mouth) |
| what are the structures that bound the nostrils/nares laterally on either side? | ala/alae meaning wing(s) |
| what's the main job of the septal cartilage (Fig. 21.2b in ppt)? | to keep shape of the nose |
| what is the anatomy of the nasal cavity? | in and posterior to the external nose & divided by a midline nasal septum; opens posteriorly into the nasal pharynx via posterior nasal apertures (choanae) |
| what bones form the roof and floor of the nasal cavity? | ethmoid and sphenoid bones form the roof; floor is formed by hard and soft palates |
| what is the (nasal) vestibule? | the nasal cavity superior to the nares; has vibrissae: hairs that filter coarse particles from inspired air |
| what do the olfactory mucosa do? | line the superior nasal cavity and contain smell receptors |
| what about the respiratory mucosa? | line the balance of the nasal cavity; glands secrete mucus containing lysozyme and defensins to help destroy bacteria |
| what are some features of inspired air? | it is not only humidified by the high water content in the nasal cavity, but it also is warmed by rich plexuses of capillaries |
| what cells remove contaminated mucus? | ciliated mucosal cells (the cells that comprise respiratory mucosa are the long-named pseudostratified ciliated columnar epithelium) |
| how many conchae bones are at the nasal cavity, what are they named/their anatomy, and what do they do? | superior, middle, and inferior conchae protrude medially from the lateral walls and increase the mucosal area; importantly, they also enhance air turbulence and help filter air, hence their name the turbinate bones |
| what structure triggers sneezing? | when sensitive mucosa are stimulated by irritating particles, the body sneezes |
| which structures filter, heat, and moisten air during inhalation? | the conchae and nasal mucosa |
| which structures reclaim heat and moisture and minimize heat and moisture loss during exhalation? | conchae and nasal mucosa |
| what are the paranasal sinuses/their anatomy and what do they do? | these are spaces in bones that surround the nasal cavity; they lighten the skull and help to warm and moisten the air, also providing resonance to the voice. located in the frontal, sphenoid, ethmoid, and maxillary bones |
| what is the pharynx and where is it located? | a funnel-shaped tube of skeletal muscle that connects to the nasal cavity/mouth superiorly and the larynx and esophagus inferiorly; extended from base of skull to the level of the sixth cervical vertebra |
| what are the 3 regions of the pharynx from superior to inferior? (NOLA) | nasopharynx, oropharynx, laryngopharynx |
| what should you know about the nasopharynx? | posterior to nasal cavity, inferior to sphenoid, superior to the level of the soft palate. strictly an air passageway unless you laught while drinking |
| what is the nasopharynx lined with? | pseudostratified CILIATED columnar epithelium |
| how is the nasopharynx prevented from having food enter it? | the soft palate (including the uvula) elevates to close off the nasopharynx during swallowing |
| what lies high on the posterior wall of the nasopharynx? | the pharyngeal tonsil. also, the pharyngotympanic (auditory, Eustachian) tubes open into the lateral walls of the nasopharynx |
| where does the oropharynx begin and end? | begins at the soft palate and ends at the upper margin of the epiglottis |
| the oropharynx opens to the oral cavity via an archway. what is this archway called? | the fauces--palatine tonsils lie in the lateral walls here; lingual tonsil covers the base of the tongue |
| true or false, it's the oropharynx that serves as a common passageway for food and air | true, but also the laryngopharynx |
| why is the oropharynx lined with stratified squamous epithelium? | for protection against abrasive food partiles being swallowed |
| what is a tonsil? | a small mass of lymphatic tissue that acts as a first line of defense for your immune system |
| where is the laryngopharynx? | posterior to the upright epiglottis; extends to the larynx |
| where do the respiratory and digestive pathways diverge? | the larynx |
| what is the anatomy of the larynx (la la la---voice box)? | attaches to the hyoid bone and opens into the laryngopharynx superiorly; continuous with the trachea posteriorly; has cartilages(!) |
| what are the 3 functions of the larynx? | provide a patent airway (means it's open and unobstructed), act as a switching mechanism to route air and food into the proper channels, function in voice production |
| what is the epiglottis? | elastic cartilage that covers the laryngeal inlet during swallowing |
| what are the (hyaline) cartilages of the larynx? | the shield-shaped thyroid cartilage with the Adam's apple known as the laryngeal prominence; signet ring-shaped anteroinferior cricoid cartilage; three pairs of small arytenoid, cuneiform, and corniculate cartilages (see Fig. 21.4a,b in ppts) |
| why are the false vocal cords so named? | they are mucosal folds superior to the true vocal cords and have no part in sound production |
| the vocal ligaments vibrate to produce sound as air rushes up from the lungs. what do they attach? | attach the arytenoid cartilages to the thyroid cartilages; the medial opening between them is the glottis |
| what are the elements of vocal production? | speech, pitch, loudness where the pharynx resonates, amplifies, and enhances sound quality. sound is shaped into language by action of the pharynx, tongue, soft palate, and lips |
| what is the intermittent release of expired air while opening and closing the glottis? | speech |
| what is the highness or lowness of voice determined by the length and tension of the vocal cords? | pitch--shorter and tighter cords = higher pitch |
| what is determined by the force with which air rushes across vocal cords? | loudness |
| describe the sphincter functions of the larynx. | the larynx is CLOSED as we build up pressure to cough or sneeze and during Valsalva's maneuver |
| describe Valsalva's maneuver | a breathing technique where you attempt to exhale forcefully against a closed airway--air is held in the lower respiratory tract by closing the glottis, abdominal muscles contract and intra-abdominal pressure rises |
| what are some additional not-necessarily-respiratory functions of Valsalva's maneuver? | helps to empty rectum, acts as a splint to stabilize trunk when lifting heavy loads, used as an orthopedic test for space-occupying lesions like tumors |
| what is the trachea? | flexibile and mobile tube from larynx into mediastinum; composed of 3 layers |
| what are the 3 layers of the trachea? | mucosa: goblet cells and ciliated epithelium; submucosa: connective tissue deep to the mucosa; adventitia: outermost layer made of C-shaped rings of hyaline cartilage |
| take note of the adventitia layer of the trachea-- | the equivalent layer inside the abdominal cavity is called the serosa |
| what is the carina? | a cartilaginous ridge separating the left and right main bronchi, marks the end of the trachea and beginning of the bronchi |
| remember that the bronchi are the last part of the conducting zone. describe the air reaching the bronchi: | the air is warm and cleansed of impurities; saturated with water vapor |
| what do the main bronchi (one to each lung) subdivide into? | lobar bronchi or secondary bronchi, each supplying a lobe of the lungs (5 total - 3 right 2 left) |
| air passages undergo how many orders of branching? | 23 |
| what is the bronchial tree? | tissue walls of bronchi mimicking that of the trachea |
| true or false, as conducting tubes become smaller, structures continue on the way they were | false, as conducting tubes become smaller, structural changes occur |
| what structural changes occur as conducting tubes become smaller? | cartilage support structures change, epithelium types change, amount of smooth muscle increases |
| describe the 3 characteristics of bronchioles (epithelium, muscle, cartilage) | consist of cuboidal epithelium, have a complete layer of circular smooth muscle, lack cartilage support and mucus-producing cells |
| how is the respiratory zone defined? | by the presence of alveoli; the first division of the respiratory zone is where terminal bronchioles feed into respiratory bronchioles |
| to what do respiratory bronchioles lead? | alveolar ducts, then to terminal clusters of alveolar sacs of alveoli |
| how many alveoli account for most of the lungs' volume? | 300 million alveoli, providing tremendous surface area for gas exchange |
| what is the air-blood barrier composed of alveolar and capillary walls and their fused basal laminas? | respiratory membrane |
| what are type I alveolar cells? | single layer of squamous alveolar cells making up the alveolar walls that permit gas exchange by simple diffusion |
| what are type II alveolar cells? | aka great alveolar cells, they secrete a detergent-like substance called surfactant |
| going back to alveoli generally, what are their general characteristics? | surrounded by fine elastic fibers; contain open pores that connect adjacent alveoli and allow air pressure throughout the lung to be equalized; alveoli also house macrophages that keep alveola surfaces sterile |
| describe the gross anatomy of the lungs, which occupy all the thoracic cavity except the mediastinum | root, costal surface, apex, base, hilum (look it up if you need a visual - note root is at hilum) |
| how many lobes does each lung have? | left has 2 lobes separated by oblique fissure, right has 3 lobes separated by oblique and horizontal fissures |
| what is the cardiac notch and which lung has it? | left lung has this cavity that accommodates the heart |
| bronchopulmonary segments or tertiary segmental bronchi are smaller than lobar (secondary) bronchi. how many per lung? | ten on the right, eight or nine on the left. |
| true or false, lungs are perfused by one ciruclation | false, lungs are perfused by two circulations: the pulmonary circulation and the bronchial circulation. pulmonary vessels take CO₂-rich blood to the alveoli for oxygenation. bronchial arteries supply oxygenated blood to the airways and support structures |
| which vessels supply systemic venous blood to be oxygenated? | pulmonary arteries which branch profusely along with bronchi; ultimately these feed into the pulmonary capillary network surrounding the alveoli |
| which vessels carry oxygenated blood from respiratory zones to the heart? | pulmonary veins |
| which vessels provide systemic blood to the lung tissue? | bronchial arteries arising from aorta and entering the lungs at the hilum, supplying all lung tissue except the alveoli |
| bronchial veins anastomose with pulmonary veins. how does this affect blood reaching the left atrium? | the oxygenated blood leaving the lungs is "polluted" a bit by deoxygenated bronchial blood joining it |
| pleurae are thin, double-layered serosa. parietal pleurae cover what areas? | covers the thoracic wall and superior face of the diaphragm, continuing around heart and between lungs |
| pleurae are thin, double-layered serosa. visceral pleurae covera what? | the external lung surface; divide the thoracic cavity into three chambers: the central mediastinum and two lateral compartments (pleural cavities) each containing a lung |
| what is the fancy name for breathing? how many phases does it have? | pulmonary ventilation has 2 phases |
| what are the 2 phases of breathing? | inspiration and expiration |
| how is inspiration accomplished? (what muscles) | air flows into lungs because diaphragm contracts (flattens downward) and external intercostal muscles assist |
| how is expiration accomplished? | air flows out the lungs because diaphragm and external intercostals relax (no active muscle contraction involved!) |
| forced expiration requires contraction of what muscles? (such as blowing out a candle) | internal intercostal muscles |
| true or false, respiratory pressure is always described relative to atmospheric pressure (Patm) | true |
| what is Patm (atmospheric pressure)? | pressure exerted by the air surrounding the body. negative respiratory pressure is less than Patm, positive respiratory pressure is greater than Patm |
| what is pressure within the alveoli called? | Ppul (intrapulmonary pressure) |
| what is pressure within the pleural cavity called? (between the visceral and parietal pleurae) | intrapleural pressure (Pip) |
| know the pressure relationships in the thoracic cavity relative to each other. which pressures fluctuate with the phases of breathing? | intrapulmonary pressure and intrapleural pressure |
| which pressure equalizes itself with atmospheric pressure? | intrapulmonary pressure (pressure within the alveoli) |
| which pressure is always less than intrapulmonary pressure and atmospheric pressure? | intrapleural pressure |
| what two forces act to pull the lungs away from the thoracic wall? | elasticity of lungs (causes them to assume smallest possible size); surface tension of alveolar fluid (draws alveoli to their smallest possible size) |
| what is the term for partial or full lung collapse? | atelectasis |
| what is the opposing force to lung elasticity and tension of alveoar fluid? | elasticity of the chest wall |
| what holds the lungs open? | lungs are held open by a combination of negative pressure in the pleural cavity and the elastic structure of the chest wall |
| what causes atelectasis? | caused by equalization of the intrapleural pressure with the intrapulmonary pressure |
| what is the formula for transpulmonary pressure, which keeps the airways open? | Ppul - Pip (intrapulmonary pressure minus intrapleural pressure) |
| pulmonary ventilation is the mechanical process that depends on what? | volume changes in the thoracic cavity. volume changes lead to pressure changes (just like in the cardiovascular), which lead to the flow of gases to equalize pressure |
| (starred) what is the sequence of inspiration (1) | the inspiratory muscles contract (diaphragm and external intercostal muscles) and the rib cage rises while diaphragm descends |
| (starred) what is the sequence of inspiration (2) | the lungs are stretched and intrapulmonary volume increases |
| (starred) what is the sequence of inspiration (3) | intrapulmonary pressure drops below atmospheric pressure to -1 mmHg |
| (starred) what is the sequence of inspiration (4) | air flows into the lungs, down its pressure gradient, until intrapulmonary pressure = atmospheric pressure again at 0 mmHg |
| (starred) what is the sequence of expiration (1) | inspiratory muscles relax and rib cage descends due to gravity and diaphragm ascends |
| (starred) what is the sequence of expiration (2) | thoracic cavity volume decreases |
| (starred) what is the sequence of expiration (3) | elastic lungs recoil passively and intrapulmonary volume decreases |
| (starred) what is the sequence of expiration (4) | intrapulmonary pressure rises above atmospheric pressure at +1 mmHg |
| (starred) what is the sequence of expiration (5) | gases flow out of the lungs down the pressure gradient until intrapulmonary pressure equalizes with atmospheric pressure again |
| is the amount of gas flowing into and out of the alveoli (ventilation) directly or indirectly proportional to the pressure difference (delta P) between the atmosphere and the alveoli? | directly proportional |
| is the amount of gas flow directly or inversely proportional to airway resistance? | indirectly/inversely, with the greatest resistance being in the medium-sized bronchi |
| (starred) true or false, as airway resistance rises, breathing movements become more strenuous | true |
| what is being obstructed or constricted during acute asthma attacks? | bronchioles... would stop ventilation |
| what hormone released via the sympathetic nervous system dilates bronchioles and reduces air resistance? | epinephrine |
| what is the term for attraction of liquid molecules to one another at a liquid-gas interface? | surface tension |
| is surfactant's job to reduce alveoli to smallest possible size or largest possible size? | smallest possible size |
| surfactant is the detergent-like liquid on alveoli that helps keep the alveoli from collapsing. does it reduce or increase surface tension? | reduce |
| what is lung compliance? | the ease with which lungs can be expanded--it's the measure of the change in lung volume that occurs with a given change in transpulmonary pressure |
| what 2 factors determine lung compliance? | distensibility of the lung tissue and surrounding thoracic cage (their stretchiness), and, surface tension of the alveoli (how forcefully they are trying to stay closed) |
| what are some factors that diminish lung compliance? | scar tissue/fibrosis, blockage of the smaller respiratory passages with mucus or fluid, reduced surfactant production, decreased flexibility of the thoracic cage or its decreased ability to expand |
| what are some examples of decreased thoracic cage flexibility/ decreased expanding ability? | deformities of thorax, ossification of costal cartilage, paralysis of intercostal muscles |
| what are the 3 types of dead space referred to in respiratory study? | anatomical, alveolar, total/physiologic |
| what is the volume of the conducting respiratory passages (150mL) where no air exchange is possible? | anatomical dead space |
| what is it called when you have alveoli that cease to act in gas exchange due to collapse or obstruction | alveolar dead space |
| what is the sum of alveolar and anatomical dead spaces? | total dead space aka physiologic dead space |
| what is the instrument consisting of a hollow bell inverted over water, used to evaluate respiratory function? | spirometer |
| spirometry can distinguish between obstructive pulmonary disease and restrictive disorders. what are these disorders? | an obstructive pulmonary disease has increased airway resistance like asthma; restrictive disorders are reductions in total lung capacity from lung changes (like pulmonary fibrosis) |
| which disease results in a barrel chest? | emphysema |
| what is Dalton's law of partial pressures? | total pressure exerted by a mixture of gases is the sum of the pressures exerted independently by each gas in the mixture; the partial pressure of each gas is proportional to its percentage in the mixture |
| what is Henry's law? | usually, when a mixture of gases is in contact with a liquid, each gas will dissolve in the liquid in proportion to its partial pressure; the amount of gas that will dissolve in a liquid also depends on its solubility |
| which gas is the most soluble? | carbon dioxide |
| which gas is 1/20th as soluble as carbon dioxide? | oxygen |
| which gas is practically insoluble in plasma? | nitrogen |
| the atmosphere is mostly which 2 gases? alveoli contain more of what? | the atmosphere is mostly O2 and nitrogen, while alveolic contain more CO2 and water vapor |
| regarding the composition of alveolar gas, why would alveoli have differences versus the atmosphere? | gas exchanges in the lungs result from O2 into the blood and CO2 from the blood; humidification of air by conducting passages; mixing of alveolar gas that occurs with each breath |
| what is external respiration? | exchange of gases between the alveoli of the lungs and the blood within pulmonary capillaries. it is a passive, diffusion-based process |
| what are 4 factors influencing movement of oxygen and carbon dioxide across the respiratory membrane? | partial pressure gradients, gas solubilities, matching of alveolar ventilation with pulmonary blood perfusion, structural characteristics of the respiratory membrane (thickness, permeability) |
| what are the numbers of the partial pressure oxygen of venous blood versus alveoli? | PO2 of venous blood is 40 mmHg; partial pressure in the alveoli is 104 mmHg |
| what does the steep gradient of venous blood versus alveoli allow for? | this way blood moves 3xs faster than normal through the pulmonary capillary (.25 sec versus .75 sec) |
| why would carbon dioxide diffuse in equal amounts with oxygen even though CO2 has a lower partial pressure gradient? | it is 20 times more soluble in plasma than oxygen, so as a result, CO2 diffuses in equal amounts with oxygen |
| regarding ventilation-perfusion coupling during external respiration, what is ventilation and what is perfusion? | ventilation is the amount of gas reaching the alveoli while perfusion is the blood flow reaching the alveoli. they must be tightly regulated for efficient gas exchange |
| regarding ventilation-perfusion coupling, changes in PCO2 in alveoli cause changes where? | diameters of the bronchioles -- passageways serving high-CO2 dilate, passageways serving low-CO2 constrict |
| how thin are respiratory membranes? | only 0.5 to 1 micrometers thick, allowing for efficient gas exchange |
| what is the total surface area of respiratory membrane surface area in comparison to one's skin? | about 40 times surface area of one's skin (60 square meters in males) |
| what happens to respiratory membranes if lungs become waterlogged and edematous? | respiratory membranes thicken, whereby gas exchange is inadequate and oxygen deprivation results |
| with emphysema, what happens to the respiratory membranes? | a decrease in surface area occurs, when walls of adjacent alveoli break down to form fewer, larger alveoli called confluent alveoli |
| what is internal respiration? | Internal respiration is the exchange of gases between the bloodstream and the body’s tissue cells. it is a diffusion process driven by partial pressure gradients, where oxygen moves from blood to cells and CO moves from cells to blood |
| what are other names for internal respiration? | tissue respiration, cellular exchange, or peripheral gas exchange |
| true or false, the partial pressures and diffusion gradients are reversed at the tissues versus the lungs | true |
| can you describe the PO2 of tissue, systemic arterial blood, and venous blood draining tissues? | PO2 in tissue is always lower than in systemic arterial blood; PO2 of venous blood draining tissues is 40 mmHg and PCO2 is 45 mmHg so at the tissue level, O2 has been unloaded and CO2 loaded |
| how is oxygen transported in the blood? | molecular oxygen is carried in the blood by being bound to hemoglobin (Hb) within red blood cells as well as dissolved in plasma |
| how many Hb molecules to how many oxygen atoms? | each Hb molecule binds four oxygen atoms in a rapid and reversible process. the Hb-O2 combination is called HbO2, or oxyhemoglobin |
| what is hemoglobin called when hemoglobin has released its oxygen? | Hhb, or deoxyhemoglobin |
| know the pathway between Hhb and O2 to HbO2 and H+ | HHb + O₂ ⇌ HbO₂ + H⁺ |
| what is the difference between partially saturated hemoglobin and saturated hemoglobin? | saturated = all four hemes of the molecule are bound to oxygen; partially = 1 to 3 hemes are bound to O2 |
| what are the things that regulate the rate that hemoglobin binds and releases O2? | PO2, temperature, blood pH, PCO2, and the concentration of BPG (an organic chemical) -- these factors ensure adequate delivery of O2 to tissue cells |
| there is an influence of PO2 on hemoglobin saturdation. on a graph it creates what is known as what? | oxygen-hemoglobin dissociation curve (Fig. 21.20) |
| true or false, if arterial blood is at 98% saturated, it contains 20 mL oxygen per 100 mL blood | true; as arterial blood flows through capillaries, 5 mL oxygen are released |
| what does the saturation of hemoglobin in arterial blood explain? | it explains why breathing deeply increases the PO2 but has little effect on oxygen saturation in hemoglobin. i.e., it has little effect on hemoglobin saturation because hemoglobin is already roughly 95-99% saturated during normal tidal breathing |
| hemoglobin is almost completely saturated at a PO2 of what? | at a PO2 of 70 mmHg. any further increases in PO2 produce only small increases in oxygen binding; O2 loading and delivery to tissue is adequate when PO2 is below normal levels |
| how much of bound oxygen is unloaded during one systemic circulation? | only 20-25% of bound oxygen is unloaded during one systemic circulation |
| if oxygen levels in tissues drop, more oxygen dissociates from hemoglobin and is used by cells. does this require increased respiratory rate or cardiac output | no (assumed up to a point?) |
| under normal circumstances, is the blood ever completely devoid of O2? | no |
| in what 3 forms is CO2 transported in the blood? | about 10 percent is dissolved in plasma, about 20% is chemically bound to hemoglobin as carbaminohemoglobin, and about 70% is transported as bicarbonate aka HCO3-(!) |
| (starred to memorize) what is the carbonic acid–bicarbonate buffer system in the body and between what step does CAH go? | CO₂ + H₂O [CAH]⇌ H₂CO₃ ⇌ HCO₃⁻ + H⁺ |
| what is CAH and what does it do? | carbonic anhydrase in RBCs reversibly catalyzes the conversion of CO2 and water to carbonic acid (Fig. 21.22a) |
| at the tissues, bicarbonate quickly diffuses from RBCs into the plasma. what is the chloride shift and why is it important here? | chloride ions (Cl-) move from the plasma into the erythrocytes to counterbalance the outrush of negative bicarbonate ions from the RBCs. importantly, it keeps the loading of CO2 going otherwise the reaction would stop |
| (starred) why is the carbonic acid–bicarbonate buffer system reversed at the lungs? | essentially, the lungs act like a vacuum for CO2, sucking it out of the system and forcing the chemistry to run backward to keep up |
| what is the reverse process of the carbonic acid-bicarbonate buffer system at the lungs? | bicarbonate ions move into the RBCs and bind with hydrogen ions to form carbonic acid |
| chloride ions move out of the blood at the lungs to balance charge. then what happens? | carbonic acid is then split by carbonic anhydrase to release CO2 and water. CO2 then diffuses from blood into alveoli |
| (starred) why is the carbonic acid–bicarbonate buffer system important? | it resists blood pH changes. if H+ ions rise, excess H+ is removed by combining with HCO3. reversely, if H+ levels drop, carbonic acid dissociates, releasing H+ |
| what's a way to alter blood pH in the respiratory system? | changing respiratory rate can also alter blood pH and provides a fast-acting system to adjust pH when it is disturbed by metabolic factors |
| what medullary respiratory centers control respiration? | the VRG and the DRG -- the ventral respiratory group and dorsal respiratory group |
| which medullary respiratory center is more important and appears to be the pacesetting respiratory center? | VRG (ventral respiratory group), contains inspiratory neurons that excite the inspiratory muscles and sets the normal/eupnea rate (12-15 breaths/minute) |
| if the doctor noted tachypnea in a patient (fast breathing), which medullary respiratory center might be unregulated? | the VRG (ventral respiratory group) |
| what is the DRG (dorsal respiratory group) involved in? | integrating information from stretch receptors and chemoreceptors |
| what is the result of reciprocal inhibition of the interconnected neuronal networks in the medulla? | respiratory rhythm |
| what determines inspiratory depth? | how actively/strongly the respiratory center stimulates the respiratory muscles |
| what determines rate of respiration? | how long the inspiratory center is active. shorter time = faster respiratory rate, longer time = slower respiratory rate |
| Fig. 21.25, what are all the factors that influence respiratory rate? | cerebral cortex, respiratory centers (medulla/pons), stretch receptors + irritant receptors in lungs, receptors in muscles/joints, central chemoreceptors of the CNS, peripheral chemoreceptors at the carotid and aortic bodies, stimuli through hypothalamus |
| do pulmonary irritants promote reflexive constriction or dilation of air passages? | constriction |
| what is the Hering-Breuer inflation reflex? | stretch receptors in the lungs are stimulated by lung inflation; upon inflation, inhibitory signals are sent to the medullary inspiration center to end inhalation and allow expiration. this prevents overinflation/lung damage! |
| regarding higher brain centers, what can modify rate and depth of respiration? | hypothalamic controls act through the limbic system to modify these (ex. breath holding that occurs in anger) |
| what are the direct signals from the cerebral motor cortex that bypass medullary controls? | corticol controls such as voluntary breath holding, taking a deep breath |
| what monitors changing PCO2 levels? | the chemoreceptors of the brain stem |
| what is the most potent stimulus for respiration and how do they build up/increase? | hydrogen ions are released when carbonic acid dissociates, which itself came from diffusing in/hydrating at the cerebrospinal fluid |
| what is hypercapnia and what is the result of it? | elevated PCO2 levels; the result is increased depth and rate of breathing to blow off the excess carbon dioxide |
| what occurs in response to hypercapnia? | hyperventilation, which quickly flushes CO2 from blood, shiftin bicarbonate buffer equation to the LEFT, decreasing H+ ions in the blood, and RAISING blood pH back to its normal range. |
| though a rise in CO2 acts as the original stimulus, control of breathing at rest is regulated by what? | the hydrogen ion concentration in the brain (Fig. 21.26) |
| what is the normal range of blood? | 7.35 to 7.45 |
| what is hypoventilation? | slow and shallow breathing, and even apnea, result from abnormally low PCO2 levels. seems counterintuitive, but hypoventilation occurs in this scenario because your body is trying to retain CO2 to restore balance |
| when the body hypoventilates, describe H+ levels, pH, and blood (too high or too low for which) | H+ would be too low, pH would be too high, and thus the blood would be too basic |
| does hypoventilation shift the bicarbonate buffer equation to the left or right? | right. it raises H+, lowers pH, and returns the blood to its normal pH range of 7.35 to 7.45 |
| what are the aortic and carotid bodies? | the primary peripheral chemoreceptors in the body. they are sensory organs that monitor the chemical composition of your blood |
| which structures monitor arterial oxygen levels? | aortic and carotid bodies |
| what is the weakest of the three stimuli of respiration? | oxygen. substantial drops in arterial PO2 to 60 mmHg are needed before O2 levels become a major stimulus for increased ventilation |
| what are the 3 stimuli of respiration from strongest to weakest? | H+ > CO2 > O2 |
| what is hypoxic drive and why would it become the principal respiratory stimulus? | in cases where carbon dioxide is not removed (e.g. emphysema and chronic bronchitis), chemoreceptors become unresponsive to PCO2 chemical stimuli and PO2 levels become the principal respiratory stimulus (hypoxic drive) |
| true or false, changes in arterial pH can modify respiratory rate even if carbon dioxide and oxygen levels are normal | true |
| what mediates increased ventilation in response to falling pH? | peripheral chemoreceptors |
| what is the most powerful respiratory stimulus? | yes, H+, but specifically the pH of CSF |
| pH of blood under 7.35 is called acidosis. what 3 things might this reflect? | CO2 retention aka respiratory acidosis, lactic acid accumulation aka metabolic acidosis, fatty acid excess in patients with diabetes mellitus aka metabolic acidosis |
| how do respiratory system controls attempt to raise pH? | increased respiratory rate and depth (hyperventilation) |
| why would someone breathe into a bag? | to stop hyperventilation by re-inhaling their own carbon dioxide to restore the body's chemical balance |
| alkalosis occurs with blood pH being over 7.45. what might this reflect? | hyperventilation causing hypocapnia (respiratory alkalosis); excessive intake of alkaline substances like antacids (metabolic alkalosis) |
| how does the body attempt to decrease pH? | hypoventilation |
| what is COPD? | chronic obstructive pulmonary disease, exemplified by chronic bronchitis and obstructive emphysema where patients have a history of smoking, dyspnea (progressively worse labored breathing), and coughing and frequent pulmonary infections |
| what is physiologically happening with oxygen and CO2 when one has COPD? | can't get oxygen into blood and carbon dioxide out of blood. COPD victims develop respiratory failure accompanied by hypoxemia, CO2 retention, and respiratory acidosis [refer to buffer equation CO₂ + H₂O [CAH]⇌ H₂CO₃ ⇌ HCO₃⁻ + H⁺] |
| what characterizes asthma? | dyspnea (progressively worse labored breathing), wheezing, and chest tightness; active inflammation of the airways precedes bronchospasms, exacerbated by fluids in airway |
| in asthma, airway inflammation is an immune response caused by release of what? | IL-4 and IL-5 (interleukins--cytosines), which stimulate IgE (immunoglobulin E) and recruit inflammatory cells |
| what causes tuberculosis? | the infectious bacterium Mycobacterium tuberculosis |
| why is tuberculosis so named? | the body forms tubercles to sequester the bacteria |
| what are symptoms of TB (tuberculosis)? | fever, night sweats, weight loss, a racking cough, and splitting headache. treatment entails 12-month course of antibiotics; there are now multi-drug-resistant strains (MDR tuberculosis) |
| what is the proportion of lung cancer deaths among cancer deaths in the U.S.? | lung cancer accounts for 1/3 of cancer deaths in the U.S. (not the most common cancer but of deaths yes) |
| true or false, 90% of all patients with lung cancer were smokers | true |
| what are the 3 most common types of lung cancer? | 20-40% squamous cell carcinoma in bronchial epithelium, 25-35% adenocarcinoma in peripheral lung area, and 20-25% small cell (oat-cell) carcinoma (more on that in another question) |
| which lung cancer contains lymphocyte-like cells that originate in the primary bronchi and subsequently metastasize, being the most aggressive of the lung cancers? | small cell (oat-cell) carcinoma |
Created by:
elianayu
Popular Anatomy sets