Lab Exam: Respiratory System Flashcards
What is minute ventilation (VE)?
total volume of air entering and leaving the respiratory system each minute
What is the formula for minute ventilation?
VTxRR (breaths/min)
What is normal VT?
500 mL
What is alveolar ventilation?
volume of air reaching the gas exchange areas per minute
What is the formula for alveolar ventilation?
(VTxRR) - (DSVxRR)
What is hyperventilation?
increased breathing rate
What does hyperventilation lead to? Why
- respiratory alkalosis
- carbon dioxide levels drop too low, pH in blood rises
What are the symptoms of hyperventilation?
- dizziness
- extremities tingle
- headache
- weakness
- fainting
What is hypoventilation?
decreased breathing rate
What does hypoventilation lead to? Why?
- respiratory acidosis
- increased concentration of carbon dioxide in the blood, pH in blood drops
What are the symptoms of hypoventilation?
- confusion
- tremors
- sleepiness
- headaches
What is normal pH? Blood pH?
- 7.4 (ranging from 7.38-7.42)
- blood pH 7.2-7.4
What is acidosis?
blood pH < 7.35
What is alkalosis?
blood pH > 7.45
What regulates pH?
- respiratory and renal systems
- CO2 levels
Name 2 buffers.
- hemoglobin
- bicarbonate
Describe how hemoglobin is used as a buffer.
- deoxyhemoglobin has greater affinity for H+
- at the tissues, hemoglobin can release O2 and bind H+ (Bohr effect)
What is FEV1?
forced expiratory volume (of FVC) in 1 second
What is normal FEV1?
> 80%
What is tidal volume (TV)?
the volume of air breathed in and out without conscious effort
What is inspiratory reserve volume (IRV)?
the additional volume of air that can be inhaled with maximum effort after a normal inspiration
What is expiratory reserve volume (ERV)?
the additional volume of air that can be forcibly exhaled after normal exhalation
What is vital capacity (VC)?
the total volume of air that can be exhaled after a maximal inhalation
What is the formula for VC?
VC = TV + IRV + ERV
What is residual volume (RV)?
the volume of air remaining in the lungs after maximum exhalation (the lungs can never be completely emptied)
What is the formula for total lung capacity (TLC)?
TLC = VC + RV
Describe obstructive disorders.
- increased resistance in airways
- difficult to inspire and expire
- hyperinflation, barrel chested
- FRC and TLC increase
- decreased PEFR
- ie. emphysema, chronic bronchitis, asthma
Describe restrictive disorders.
- decreased lung compliance
- decreased FVC, TLC, and VC
- decreased PEFR and volume
- ie. scoliosis, pulmonary fibrosis
What is PEFR?
peak expiratory flow rate
What is normal PEFR in males?
~9 L/sec
What is normal PEFR in females?
~7 L/sec
What is forced vital capacity (FVC)?
the total exhaled air, from maximum inhalation to maximum exhalation
____/_____ measured as a percentage.
FEV1/FVC
What is peak expiratory flow (PEF)?
the highest point on the exhalation graph
What are buffers?
- chemicals that help resist changes in pH
- help to maintain pH within a normal (very narrow) range
CO2 is buffered in the blood by…
- conversion to bicarbonate
- process reverses at the lungs to get rid of CO2
