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AP Quiz 3-Pulmonary Dynamics

Terms in this set (40)

What are the purposes of breathing?
1) Exchange of O2
2) Exchange of CO2
3) Control of blood acidity
4) Oral communication
Where in the body is the O2 and CO2 exchanged?
Alveoli
What the process of ventilization result in?
Higher PO2 in lungs than in the metabolizing tissues
What is ventilation?
movement of air in and out of the lungs
What is respiration?
Cellular utilization of O2
What two ways are inspiration and expiration regulated in?
Frequency
Volume
What is the more efficient way to breathe?
More efficient to breathe deep and less often (increase Vt and decrease F)
What does respiratory cycle result from?
The inherent and automatic activity of inspiratory neurons whose cell bodies are in the medulla
What are chemoreceptors?
Specialized neurons that monitor blood conditions, provide feedback
What is pulmonary ventilation at rest regulated by?
Chemical state of the blood
What do reduced O2 pressures stimulate?
Peripheral chemoreceptors (carotid and aortic bodies)
What do reduced O2 pressures activate?
Aortic and carotid chemoreceptors to increase ventilation
What do peripheral chemoreceptors do?
Protect against decreases in PaO2 and stimulate ventilation in response to increase in PaCO2, temperature, metabolic acidosis, a decrease in BP, changes in H+, and exercise
-Protect against arterial hypoxia in ascent to higher altitudes and help to regulate exercise hyperpnea
What happens in phase I of exercise? (Rapid rise)
There is a rapid rise in ventilation as exercise begins
What is phase I controlled by?
The neurogenic stimuli from the cerebral cortex combined with feedback from the active limbs stimulates the medulla to abruptly increase ventilation; after a 20 sec. pause, VE then rises exponentially
What happens in phase II of exercise? (Rise to steady state)
Ventilation continues to rise until it reaches a steady state in relation to the demands for metabolic gas exchange
What is phase II regulated by?
Cerebral cortex and factors intrinsic to neurons of the respiratory control center
What happens in phase III of exercise? (Steady State)
The fine tuning of the steady state is through the peripheral chemoreceptors and the cerebral cortex
What happens during recovery phase of exercise?
The initial rapid decrease is due to the abrupt removal of the cerebral cortex and the stoppage of movement
How does ventilation increase in light and moderate exercise?
Increases linearly with VO2 and VCO2
How is ventilation increased?
Through increasing VT
What happens to VO2 and VE in steady state?
They plateu
What happens to VE during more intense exercise?
VE takes a sharp upswing and increases disporportionately with the increasing VO2
How is the ratio of VE to VO2 symbolized?
VE/VO2
What is the VE/VO2 during non-steady state ventilation?
35
What is OBLA?
Onset of blood lactate accumulation
When does OBLA occur?
Occurs between 55-65% VO2 max in healthy untrained subjects; untrained subjects OBLA can occurs at 70% or higher of their VO2 max
What is ventilatory threshold?
Point where VE and VCo increases disproportinately to VO2 during graded exercise. AKA anaerobic threshold
What is Lactate Threshold?
Describes the highest VO2 or exercise intensity before a 1.0 mM increase in blood lactate concentration above the pre-exercise level
T/F: It is fond that African and South African endurance runners show greater resistance to fatigue at the same percentage of peak treadmill running velocity than Caucasian counterparts despite similar values for VO2 Max
TRUE
What factors are OBLA determined by?
-Muscle fiber type activated
-Capillary density
-The mitochondrial size and number
-Alteration in a muscle's enzymatic and oxidative capabilites
What factors are VO2 max determined by?
-Absolute quantity of muscle mass activated
-Functional capacity of CVS
Where is the respiratory center of the brain located?
Medulla
What receptors protect against a decrease in PaCO2?
Peripheral chemoreceptors
What is the most important stimulus for breathing in a healthy person?
CO2 pressure
During steady state, LA does not form. Explain
There is sufficient O2
At what point in VO2 max does LA form?
around 55% VO2 max
What buffers the increase of LA in the blood due to an increase in anaerobic metabolism?
NaHCO2
What increases in response to the accumulation of LA?
VE and VCO2
Explain why ventilation does not limit aerobic performance except in the elite athlete
There is a greater capacity to increase ventilation (35 fold) during aerobic exercise than Q (6 fold)
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