Download Respiratory System: Expiration, Muscles, Volumes, and Ventilation Terms and more Quizzes Health sciences in PDF only on Docsity!
Functions of the pulmonary system
supply oxygen required in metabolismeliminate CO produced in metabolismregulate hydrogen ion concentration to maintain acid-base balance TERM 2
Describe how air gets into the lungs
DEFINITION 2 diaphragm contracts, flattens out and moves downward toward the abdominal cavity the air in the lungs expands, reducing its pressure below atmospheric pressure the pressure differential between the lungs and ambient air sucks air in through the nose and mouth, and inflates the lungs inspiration concludes when the thoracic cavity expansion ceases and intrapulmonic pressure increases to equal atmospheric pressure TERM 3
Muscle activation during exercise and
ventilation
DEFINITION 3 scalenes and external intercostals contract causing the ribs to rotate and lift up and away from the body TERM 4
Air moves into the lungs when the chest
cavity volume increases from what 3 factors?
DEFINITION 4
- descent of diaphragm2. upward lift of ribs3. outward thrust of sternum TERM 5
Expiration is what kind of process
DEFINITION 5 passive process as air moves out of the lungs from the recoil of stretched lung tissue and relaxation of inspiratory muscles
What happens to the chest cavity during
expiration?
the sternum and ribs swing down while the diaphragm moves toward the thoracic cavitythese movements decrease chest cavity volume and compress alveolar gas forcing it out thorugh the respiratory tract to the atmosphere TERM 7
What do the muscles do during ventilation in
moderate to intense exercise?
DEFINITION 7 the intercostals and abdominals act powerfully on the ribs and abdominal cavity to produce rapid and greater depth of exhalation thus inducing larger pressure differentials and concimitant increases in air movement TERM 8
Tidal volume
DEFINITION 8 air moved during either the inspiratory or expiratory phase of each breathing cycleranges from .4-1.0 L of air per breath TERM 9
Inspiratory reserve
volume
DEFINITION 9 the max volume of air that can be inhaled after a normal inspirationadditional volume of 2.5-3.5 L above TV represents reserve for inhalation TERM 10
Expiratory reserve
volume
DEFINITION 10 the max volume of air that can be expelled from the lungs after normal expiration1.0-1.5 L
forced expiratory volume to FVC ratio
FEV1.0/FVC ratioreflects expiratory power and overall resistance to air movement in the lungsavgs 85%in COPD can be as low as 40% TERM 17
Minute ventilation
DEFINITION 17 VEthe volume of air breathed each minutethe total volume of gas entering the lungs per minuteVE = Breathing rate x Tidal Volume TERM 18
Alveolar ventilation
DEFINITION 18 the volume of gas per unit time that reaches the alveoli, the respiratory portions of the lungs where gas exchange occurs TERM 19
Physiological dead space
DEFINITION 19 the volume of air which is inhaled that doesn't take part in the gas exchange either because it reamins in the conducting airways or it reaches alveoli that are not perfused or poorly perfused TERM 20
Physiological dead space can increase to 50%
of resting tidal volume because of what?
DEFINITION 20 inadequate perfusion during hemorrhage or blockage of the pullmonary circulation from an embolism or blood clotinadequate alveolar ventilation in chronic pulmonary disease
Hyperventilation
an increase in pulmonary ventilation that exceeds the oxygen needs of metabolismlowers normal alveolar CO concentration which causes excess CO2 to leave body fluids via expired airan accompanying decrease in hydrogen ions increases plasma pH TERM 22
Spontaneous respiration is produced by
what?
DEFINITION 22 rhythmic discharge of motor neurons that innverate the respiratory musclesdischarge dependent on nerve impulses from the brain TERM 23
When does breathing stop?
DEFINITION 23 if the s.c. is transected above the origin of the phrenic nerves TERM 24
The rhythmic discharges from the brain that
produce spontaneous respiration are
regulated by what?
DEFINITION 24 alterations in arterial Po2, PCO2 and H+ concentration and this chemical control of breathing is supplemented by a number of nonchemical influences TERM 25
Neural factors that control
ventilation
DEFINITION 25 normal respiratory cycle comes from inherent automatic activity of inspiratory neurons whose cell bodies reside in the medulla of the brainlungs inflate because neurons activate the diaphragm and intercostal muscles
What provides the most important respiratory
stimulus at rest?
CO2 pressure in arterial plasma TERM 32
Where are chemoreceptors located?
DEFINITION 32 in the arch of the aorta (aortic bodies) and at the branching of carotid arteries of the neck (carotid bodies) TERM 33
Where in the brain are the ventilation controls
DEFINITION 33 the medulla oblongata and ponsSTIMULATION:respiratory rhythmicity center = ventral respiratory group (VRG) and dorsal respiratory group (DRG)the apenuestic centerINHIBITION:pneumotaxic center TERM 34
Plasma PO2 and chemoreceptors
DEFINITION 34 inhaling gas mix of 80% O2 increases P02 and reduces minute ventilation by 20%conversely reducing inspired oxygen concentration increases minute ventilation particularly if alveolar PO2 decreases below 60mm Hg (hypoxic threshold) TERM 35
Sensitivity to reduced arterial oxygen
pressure (arterial hypoxia) results from what?
DEFINITION 35 stimulation of peripheral chemoreceptors, aortic bodies and carotid bodies
Peripheral chemoreceptors provide an early
warning system for what?
to alert against reduced oxygen pressurealso stimulates ventilation in response to increased CO2, acidity and temperature and decrease in BP TERM 37
What provides the most important respiratory
stimulus at rest?
DEFINITION 37 CO2 in arterial plasma TERM 38
Small increases in PCo2 of inspired air do
what?
DEFINITION 38 stimulate the medulla and peripheral chemoreceptors to initiate larger increases in minute ventilation TERM 39
Describe the role molecular CO2 plays on
ventilatory control
DEFINITION 39 carbonic acid formed from the union of CO2 and H2O rapidly dissociated to bicarbonate ions and hydrogen ionsthe increase in hydrogen which varies directly with the bloods CO2 content in the CSF bathing the respiratory ares stimulates inspiratory activitythe resulting increase in ventilation eliminates CO2 which lowers arterial hydrogen TERM 40
Chemical factors that control ventilation
during exercise
DEFINITION 40 Po arterial PO2 in exercise doesnt decrease to the point that stimulates ventilation by chemoreceptor activation Pco H+ chemical stimuli cannot fully explain the increased ventilation during physical activity
VO2 max
the highest rate of oxygen transport and use that can be acheieved at max physical exertion TERM 47
Onset of blood lactate accumulation is
indicated by what?
DEFINITION 47 the eventual sharp upswing in pulmonary ventilation related to oxygen uptake during incremental exercise TERM 48
OBLA implies what?
DEFINITION 48 an imbalance between the rate of blood lactate appearance and disappearancemay not result from muscle hypoxia rather it may result from decreased lactate clearance or increased lactate production only in specific muscle fibers TERM 49
When does OBLA occur?
DEFINITION 49 55-65% of VO2 MAX in healthy untrained subjects and often equals more than 80% in highly trained athletespoint of OBLA often increases with aerobic training without an accompanying increase in VO2 max TERM 50
Gas exchange in the body
DEFINITION 50 exchange of gases between lungs and blood and their movement at the tissue level takes place passively by diffusion
Gas exchange in the lungs
the first step in O2 transport involves the transfer of O2 from the alveoli into the blood TERM 52
Gas exchange in the tissues
DEFINITION 52 oxygen leaves capillary blood and flows toward metabolizing cells while CO2 flows fomr the cell into the blood TERM 53
Oxygen transport in the blood is completed
with what?
DEFINITION 53 combined with hemoglobin in the RBCincreases the blood's oxygen carrying capacity to 65-70 times that normally dissolved in plasma
