Respiratory system 2: Pulmonary Ventilation Flashcards
External (pulmonary) respiration
The process of gas exchange between the alveoli of the lung and the blood in the pulmonary capillaries
Pulmonary respiration
The process of gas exchange between the air we breathe (atmosphere) and the alveoli of the lungs
Internal (pulmonary) respiration
The process of gas exchange between the systemic capillaries and the tissue cells
Boyle’s law
The pressure of a gas in a closed container is inversely proportional to the volume of the container
The most important muscle Invovled in inhalation/inspiration
Diaphragm (accounting 75% of contraction) and external intercostals (accounting 25% of contraction)
Quiet Inspiration/inhalation
Diaphragm descends 1 cm and ribs lifted by muscles
external intercostals elevate the ribs increasing the dimensions of the chest cavity
Inhalation of about 500ml of air
Forced inhalation
accessory muscles of inspiration (SCM, scalenes and pectoralis minor) are also used to lift chest upward as you gasp for air.
Diaphragm descends 4 cm
Intrathoracic pressure falls and 2-3 liters inhaled
Exhalation occurs when…
Alveolar (intrapulmonic) pressure is higher than atmospheric pressure.
Quiet expiration
Passive process with no muscle action
Elastic recoil and surface tension in alveoli pulls inward
Alveolar pressure increases and air is pushed out
Forced expiration
Exhalation becomes active during labored breathing and when air movement out of the lung is impeded. Internal intercostals depress ribs and abdominal muscles force diaphragm up.
Intrapleural pressure
is the pressure between the parietal and visceral layers of the lungs
Always subatomospheric
As diaphragm contracts and volume of Thracic cavity increases, volume of the pleural cavity also increases which causes intrapleural pressure to decreases even more
Helps keep parietal and visceral pleura stuck together when chest expands
Alveolar surface tension
Thin layer of fluid in alveoli causes inwardly directed force = surface tension
water molecules strongly attracted to each other causes alveoli to remain as small as possible
What does Type II alveolar cells produce?
Surfacant, detergent-like substance lowers alveolar surface tension. Insufficient in premature babies so that alveoli collapse at end of each exhalation
What is compliance of the lungs
Ease with which lungs and chest wall expand depends upon elasticity of lungs and surface tension
Some diseases reduce compliance
Which diseases reduce compliance of the lungs
Tuberculosis forms scar tissue
Pulmonary edema - fluid in lungs and reduced surfacant
Paralysis
Airway resistance
Resistance to airflow depends upon airway size
Increase size of chest - airways increase in diameter
contract smooth muscles in airways - decreases in diameter
Normal variation in breathing rate and depth is called
Eupnea
Breath holding is called
Apnea
Painful or difficult breathing is called
Dyspnea
Rapid breathing rate is called
Tachypnea
combinations of various patterns of intercostal and extracostal muscles, usually during need for increased ventilation as with exercise
Costal breathing
Usual mode of operation to move air by contracting and relaxing the diaphragm to change the lung volume
Diaphragmatic breathing
Used to express emotions and to clear air passageways
Modified respiratory movements
deep inspiration, closure of rima glottidis and strong expiration blasts air out of clear respiratory passages
Coughing