Question | Answer |
respiratory system | organs that oversee gas exchanges occurring between blood & external enviroment |
The respiratory membrane is | very thin |
the thin respiratory membrane allows rapid ______ of O2and CO2 | diffusion |
The superior, middle, and inferior nasal conchae serve to | increase the mucosal surface area and increase air turbulence in the nasal cavity |
A normal tidal volume is about | 500 ml |
normal tidal volume represents the amount of air | moved into and out of the lungs with each breath |
Most of the carbon dioxide (CO2) carried in the blood is carried as | the bicarbonate ion (HCO3-) in plasma |
O2 loading & CO2 unloading between pulmonary capillary blood & air in alveoli is called | external respiration |
The amount of air that enters and leaves the lungs through normal quiet breathing is known as the | tidal volume |
Over 90% of lung cancers are associated with | smoking cigarettes |
The acronym COPD is the abbreviation for | Chronic Obstructive Pulmonary Disease |
surfactant is | a lipid |
surfunctant acts to raise the surface tension | of water with the alveoli |
The most common lethal genetic disease in the United States is | cystic fibrosis |
respiratory zone | bronchioles, alveolar ducts & sacs, & alveoli; only site of gas exchange |
conducting zone structures | serve as conduits to & from respiratory zone; includes all other resp. passageways not in resp zone |
terminal bronchioles lead into | respiratory zone structures |
respiratory zone structures terminate in | the aveoli |
network of branching/rebranching respiratory passageways within lungs is referred to as | brochial tree/respiratory tree |
stroma | elestic connective tissue of lungs allowing it to reoil passively on exhalation |
walls of alveoli are composed largely of | single, layer of squamous epithelial cells |
alveolar pores | connect neighboring air sacs, providing alt. routes for air to reach alveoli |
external surfaces of alveoli are | covered with "cobweb" of pulmonary capillaries |
respiratory membrane is also called | air-blood barrier |
the air-blood barrier is constructed of | avleolar & capillary walls, fused basement membranes & occasional eleastic fibers |
has gas (air) flowing through on one side & blood following through on the other side | the air-blood barrier |
oxygen passes from the alveolar air into | the capillary blood |
carbon dioxide leaving capillary blood enters | the gas-filled alveoli |
alveolar macrophages are sometimes called | "dust cells" |
wander in & out of alveoli picking up bacteria, carbon particles & other debris | alveolar macrophages |
there are cuboidal cells scattered among | the epithelial cells forming most of alveolar walls |
produce lipid molecule called surfunctant, which is very important to lung function | cuboidal cells of alveoli |
major function of respiratory system is to | supply blood with oxygen & dispose of cardob dioxide |
four distinct events allowing respiratory system to complete their function | collectively called respiration |
pulmonary ventilation | air must move in/out of lung so gases in alveoli are continuously refreshed |
process of pulmonary ventilation is called | breathing |
external respiration | gas exchange between pulmonary blood & alveoli |
gas exchanges are being made between blood & exterior in | external respiration |
repiratory gas transport | O2 & CO2 must be transported to/from lungs & tissue cells of body via bloodstream |
internal respiration | at systemtic capillaries gas exchnaged between blood & tissue cells |
gas exchanges occur between blood & cells inside body during | internal repsiration |
cellular respiration | actual use of O2 & CO2 produced by tissue cells |
cornerstone of all energy-producing chemical reactions in the body | cellular respiration |
breathing is a completely mechanical process that depends on volume exchanges occurring in | the thoracic cavity |
volume changes lead to | pressure changes |
pressure changes lead to | flow of gasses to equalize pressure |
unlike liquid, gas | fills its container |
in a large volume gas molecules will be far apart and the pressure is | low |
pressure is created by the gas molesules | hitting eachother & walls of container |
if volume is reduced the gas molecules will be closer together and the pressure is | rising |
inspiration | when air is flowing into the lung |
expiration | when air is leaving the lungs |
inspiratory muscles are | the diaphragm & external intercostals |
when inspiratory muscles contract the size of the thoracic cavity | increases |
when diaphragm contracts it moves | inferiorly & flattens out, or is depressed |
result of diaphragm contraction, superior-inferior dimension of thoracic cavity | will increase |
contraction of external intercostals | lifts rib cage & thrusts sternum forward |
contraction of external intercostals increases the | anteriorposterior & lateral dimensions |
the lungs adhere tightly to the thorax walls due to | surface tension of fluid between pleural membranes |
the lungs are stretched to the new, larger size of the thorax because | they are bound to the walls of the thorax |
intrapulmonary volume | volume within lungs |
when intrapulmonary volume increases, gases within lungs | spread out to fill the larger space |
when pressure in the lungs is less than atmospheric pressure | a partial vacuum is produced, which sucks air into the lungs |
in healthy people this is largely passive process depending on natural elasticity | expiration |
when inspiratory muscles relax & resume intial resting length, | the rib cage descends & lungs recoil |
intrapulmonary volume decreases, gases in lungs forced closer together then | intrapulmonary pressure rises to a point higher than atmospheric pressure |
when intrapulmonary pressure rises to a point higher than atmospheric pressure it causes | gases to flow out to equalize pressure inside/outside lungs |
unde normal circumstances expiration is | effortless |
if respiratory passageways are narrowed by spasms or blocked with mucus/fluid | expiration becomes an active process, or forced expiration |
during forced expiration internal intercostal muscles | are activated to help depress rib cage |
during forced expiration abdominal muscles contract & help | to force air from lungs by squeezing abdominal organs upward against diaphragm |
intrapleural pressure | normal pressure within plueral space always negative |
major force preventing collapse of lungs | negative pressure within plueral space |
if intrapleural pressure becomes = to atmospheric pressure | the lungs immediately recoil completely & collapse |
atelectasis | collapsed lung |
when a lung is collapsed it is | useless for ventilation |
when air enters pleural space, due to a chest wound it is normal for a | atelectasis to occur |
atelectasis can also result from | rupture of visceral pleura |
rupture of visceral pleura allows | air to enter plueral space from respiratory tract |
pneumothorax | presence of air in intrapleural space, disrupting fluid bond between pleurae |
revered by drawing air out of intrapleural space with a chest tube | pneumothorax |
when a pneumothorax is relieved with a chest tube this allows | lung to reinflate & resume its normal function |
nonrespiratory air movements | result from a reflex activity, but some are produced voluntarily |
cough, sneeze, cry, laugh are all examples of | nonrespiratory air movements |
inspiratory reserve volume (IRV) | amount of air that can be taken in forcibly over the tidal volume |
between 2100 & 3200ml is the | normal IRV |
expiratory reserve volume (ERV) | amount of air that can be forcibly exhaled after tidal expiration |
1200ml is the approximate | normal ERV |
residual volume | even after strenuous expiration, the 1200ml of air remaining in lungs, that can't be expelled |
important because allows continuous gas exchange between breaths & keeps alveoli open | residual volume |
vital capacity (VC) | sum of TV + IRV + ERV |
dead space volume | amount of air remaining in conducting zone passageways, never reaching alveoli |
150ml is the amount of | dead space volume during a normal tidal breath |
spirometer | instrument used to measure respiratory capacity |
useful in evaluating losses in respiratory functioning & follow course of respiratory diseases | spirometer |
inspiration is obstructed causing decrease in IVR & VC | in pneumonia |
expiration hampered, causing ERV to be lower than normal & residual volume is higher | in emphysema |
bronchial sounds | produced by air rushing through trachea & bronchi |
vesicular breathing sounds | occur as air fills alveoli, soft & resemble muffled breeze |
crackle | bubbling sound |
wheezing | whistling sound |
abnormal respiratory sounds due to disease, mucus or pus | crackle & wheeze |
all gas exchanges are made according to | laws of diffusion |
duffusion | movement occurs toward area of lower concentration of diffusing substance |
dark red blood is found | flowing through pulmonary circuit |
dark red blood is transformed into scarlet when | returned to heart for distribution to systemic circuit |
color change of dark red to scarlet blood is due to | oxygen pickup by hemoglobin in lungs |
there is more oxygen in the | alveoli, than in the lungs |
because concentration of CO2 higher in pulmonary capillaries than avleolar air, it | will move from blood into alveoli & be flushed out of lungs during expiration |
oxyhemoglobin | oxygen attaches to hemoglobin molecules inside RBCs |
small amount of oxygen in carried dissovled in | the plasma |
enzymatic conversion of CO2 to bicarbonate ion occurs within | RBCs |
once coverted into bicarbonate ion it | diffuses into the plasma |
CO2 carried inside RBCs is bound to hemoglobin at | different site than O2 |
before CO2 can diffuse out of blood into alveoli | it must be released from bicarbonate ion form |
enter RBCs combining with H+ to form carbonic acid | process for CO2 to be released from bicarbonate ion form |
carbonic acid splits to form | water & CO2, which diffuses from blood into alveoli |
hypoxia | inadequate O2 delivery to body tissues |
cyanotic | skin & mucosa take on bluish cast due to lack of O2 |
hypoxia can be result of | anemia, pulmonary disease or impaired/blocked blood circulation |
leading cause of death from fire | carbon monoxide poisening |
carbonic anhydrase | speeds upreaction of bicarbonate ions converting to carbonic acid |
nerve impulses from brain to diaphragm & external intercostals travel by | phrenic or intercostal nerves |
neural centers that control respiratory rhythm are located | deep in the medulla & pons |
medulla | sets basic rhythm of breathing & contains self-exciting inspiratory center |
self-exciting inspiratory center | located in medulla; neurons fire impulses to travel to phrenic/instercostal nerves |
medulla also contain expiratory center which | inhibits pacemaker in rhythmic way |
eupnea | normal respiration of rate 12-15 respirations/minute |
pons centers | smooth out basic ryhthm of inspiration/expiration set by medulla |
bronchioles & alveoli have stretch receptors that respond to | extreme overinflation by initiating protective reflexes |
in case of overinflation ____ send inpulses from stretch receptors to medulla | vagus nerves |
hyperpnea | increased deep breathing, which may/may not be accompanied by increase in respiratory rate |
Maximal hyperpnea occurs during | strenuous exercise |
overdose of sleeping pills, morphine or alcohol can lead to | medullary centers being completely suppressed causing respiration to stop, and death |
concious control of breathing will be overtaken by | involuntary controls once O2 supply becomes low or blood pH falls |
emtional factors can modify the | rate & depth of breathing |
emotional factors result from reflexes initiated by emotional stimuli acting | through centers in hypothalamus |
most important stimuli leading to increase in rate & depth of breathing | increased CO2 & decreased blood pH |
changes in CO2 levels in blood act directly on | medulla centers by influencing pH of cerebrospinal fluid |
peripheral chemoreceptors in aorta & fork in common cartoid artery detect | changes in O2 concentration in blood |
send impulses to medulla when blood O2 levels are dropping | peripheral chemoreceptors in aorta & fork in common cartoid artery |
the most stimulus for breathing in a person is the body's need to | rid itself of CO2 |
hyperventilation | abnormally fast and deep breathing |
blows off more CO2, decreasing amount of carbonic acid & returns blood pH to normal | hyperventilation |
hypoventilation | reduced amount of air entering alveoli, which causes increase in arterial CO2 level |
acidosis | accumulation of acid & hydrogen ions; depletion of alkaline reserve in blood & body tissues, resulting in decrease in pH |
alkalosis | decrease in hydrogen ion concentration of blood (increase in pH) |
when the buffering ability of blood is overwhelmed the result is | acidosis/alkalosis |