Respiratory Flashcards
The lung is suitable for gas exchange because ….. & …..
- Large surface area (70 square meter, about 40 times the surface area of the body)
- Blood-gas barrier is thin (less than 0.5 micro meter)
The blood gas barrier is composed of …. , ….. & …..
alveolar epithelium, basement membrane, capillary endothelium
The conducting zone of the lung is ….., …., ….. & ….. . This is also called …..
trachea, bronchi, bronchioles & terminal bronchioles
* called anatomic dead space (volume is about 150 mL)
The respiratory zone has a volume of … , and consists of …., …. & ….
3000 mL
respiratory bronchiole, alveolar duct, alveolar sacs
There are about …… alveoli in both lungs
300 million
Alveolar sacs are ….. at the end of
blind pouches, terminal bronchiole
Air travels in the conducting zone via …. due to …..
bulk flow
small cross section
Define:
- Vt
- IRV
- ERV
- RV
- amount inspired and expired with every normal breath (about 500mL)
- The extra volume that can be inspired over the Vt
- The extra volume that can still be expired beyond Vt
- The volume remaining after maximal expiration
Define:
- TLC
- VC
- FRC
- IC
- maximum volume to which the lung can be expanded.
- is TLC - RV (max expiration after max inspiration)
- RV + ERV
- TV + IRV (the total volume that can be inhaled after normal expiration)
FRC is an important buffer because ….
prevents extreme changes in alveolar PO2 with each breath, otherwise, PO2 will be equal to that of venous blood at the end of each expiration
FRC & TLC can be measured with ……
gas dilution or plethysmography
- due to the presence of RV
- Note: RV increases with age, COPD & asthma due to air trapping
- Gas dilution is measured with helium gas. This method is used to measure RV
FEV 1 is ….
volume expelled after one second.
* a person can exhale about 80% of VC in one second
FEV 1 is reduced in ….. & ….. , however, there is a difference. What is it?
obstructive airway disease & restrictive airway disease
- In restrictive diseases (fibrosis), all volumes are reduced and the flow rate is reduced proportionately. So FEV 1 : VC is normal.
- In obstructive diseases (emphysema, asthma, chronic bronchitis etc..), FEV1 : VC is disproportionately reduced, and is a measure of the disease severity.
Minute ventilation (Vm) is ….
the volume of air entering the airway each minute (about 6 liters, 500mL x 12 breath/min)
Anatomic dead space is decreased by …. & …. . The normal volume for this space is ….
tracheostomy & pneumonectomy (removal of a lung)
150 mL
* Lobectomy is removal of lobe, not the whole lung
Alveolar ventilation (Va) is ……..
the volume of air entering the alveoli per unit time
- Va = R rate x (TV - volume of dead space)
- Va is about 350 mL for each breath
Physiologic dead space includes both ….. & …..
anatomic dead space + non functional alveolar space (due to poor ventilation)
* measure by Bohr’s equation (ratio of dead space to Vt)
Upper regions of the lung is better ventilated. T/F?
False
lower regions are better
* Because the upper parts are suspended by the trachea and are more stretched, while the lower parts are not. The upper parts are not very well ventilated because there is no room for expansion
The same goes for the blood vessels (more stretched means less perfused)
The lung extends from above …., …. ant, …. lat, & … post
clavicle, 8 rib, 10 rib, 12 rib
Blood supply to the lung is through …. & …..
bronchial, pulmonary arteries
* most of bronchial blood is returned by the pulmonary vein
The pulmonary circulation has low …..
resistance & high blood flow
* To accommodate more blood without increasing pressure through recruitment of unperfused capillaries
Hypoxia …. pulmonary vascular resistance
increases
Effortful inspiration requires ….. & …. muscles, while effortful expiration requires …… & ……
scalene & SCM muscles, trapezius & ext. intercostals
abdominal & internal intercostal muscles
Obstructive lung disease increases ……, while restrictive diseases decreases ….
resistance
compliance