Questions and Answers
Under what internal conditions does air tend to flow into the lungs?
When thoracic volume increases, pressure decreases.
Under what internal conditions does air tend to flow out of the lungs?
When thoracic volume decreases, pressure increases.
What effect does contraction of the diaphragm and external intercostal muscles have on thoracic volume?
The contraction increases thoracic volume.
What was the approximate increase in diameter of chest circumference during a quiet inspiration?
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What would happen if an opening were made into the chest cavity, as with a puncture wound?
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What must be done to treat a puncture wound in the chest cavity?
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What respiratory volume/capacity measurement does inhaling slowly from the incentive spirometer approximate?
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What is the volume of air present in the lungs after a forceful expiration?
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Which respiratory ailments can respiratory volume tests be used to detect?
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Where are the neural control centers of respiratory rhythm located?
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After breathing quietly and taking a deep breath, was there an urge to inspire or expire?
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Why does hyperventilation produce apnea or a reduced respiratory rate?
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What was the effect of running in place (exercise) on the duration of breath holding?
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Why does rebreathing air produce an increased respiratory rate?
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Where are sensory receptors sensitive to changes in blood pressure located?
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Where are sensory receptors sensitive to changes in O2 levels in the blood located?
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What is the primary factor that initiates breathing in a newborn infant?
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Did it appear that CO2 or O2 had a more marked effect on modifying the respiratory rate?
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When blood CO2 levels increase, does the pH increase or decrease?
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Study Notes
Respiratory Mechanics and Observations
- Air flows into the lungs when thoracic volume increases, causing pressure to decrease.
- Air flows out of the lungs when thoracic volume decreases, leading to an increase in pressure.
- Gases move to equalize pressure differences both inside and outside the container.
Muscle Activation in Breathing
- Contraction of the diaphragm and external intercostal muscles initiates inspiration.
- This contraction results in an increase in thoracic volume.
Chest Circumference and Inspiration
- During quiet inspiration, chest circumference increases slightly; during forced inspiration, the increase is substantial.
- Greater chest circumference during forced inspiration enhances the efficiency of air intake.
Impact of Pleural Membrane Integrity
- The presence of a partial vacuum between pleural membranes is essential for normal lung function.
- A punctured chest cavity disrupts this vacuum, inhibiting lung function; treatment involves air withdrawal and wound closure.
Respiratory Volumes and Spirometry
- Experimental spirometer activities measure lung volumes; corrected values and FEV1 are used for precise recordings.
- Incentive spirometry measures respiratory volume by inhaling through a mouthpiece slowly and completely.
Definitions of Respiratory Volumes
- Residual Volume (RV): Air left in lungs after forceful expiration.
- Expiratory Reserve Volume (ERV): Air that can be forcibly expired after a normal exhalation.
- Tidal Volume (TV): Air exchanged during normal respiration.
- Inspiratory Reserve Volume (IRV): Air that can be forcibly inhaled after a normal inhalation.
- Vital Capacity (VC): Total volume of air during TV + IRV + ERV.
Respiratory Volume Measurement Techniques
- Non-recording dry spirometers can evaluate respiratory volumes and capacities through systematic inhalation and exhalation measurements.
Respiratory Ailments Detection
- Respiratory volume tests reveal conditions such as asthma, chronic obstructive pulmonary disease (COPD), and restrictive lung disease.
Neural Control of Respiration
- Respiratory rhythm is regulated by neural control centers located in the brainstem.
Effects of Breath-holding and Hyperventilation
- Breath-holding intervals vary after deep inhalation and forced expiration, influenced by underlying reflex mechanisms.
- Hyperventilation leads to a temporary cessation of breathing or apnea by reducing carbon dioxide levels in the blood.
Impact of Exercise on Breathing
- Physical activity like running increases metabolic demand, shortening breath-holding duration due to elevated respiratory rates.
Rebreathing Air Effects
- Rebreathing results in increased respiratory rates due to a rise in carbon dioxide levels, prompting the body to initiate breathing.
Sensory Receptors for Breathing Control
- Blood pressure sensors are located in the aortic arch and carotid arteries.
- Sensors for oxygen levels are found in the carotid and aortic bodies.
Initiation of Breath in Infants
- The primary factor initiating breathing in newborns is the increase in carbon dioxide levels once exposed to the atmosphere.
Factors Influencing Respiratory Rate
- Increases in blood CO2 and decreases in blood O2 raise the respiratory rate.
- A decrease in blood pH also leads to a higher respiratory rate; an increase in blood pH has the opposite effect.
- CO2 levels generally have a more significant influence on modifying respiratory rates.
Relationship Between CO2 Levels and Blood pH
- Elevated CO2 levels in blood result in decreased pH due to the formation of carbonic acid, which dissociates into hydrogen and bicarbonate ions; this explains the relationship between the two.
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Description
This quiz focuses on the observations noted during a model lung experiment. It encourages understanding of the internal conditions affecting airflow in and out of the lungs. Answer the questions based on your observations to solidify your comprehension of respiratory mechanics.
