The Respiratory System (Lecture 2)

surfactant reduces the _________ forces between ______ on the alveolar surface

surfactant reduces the surface tension forces between water molecules on the alveolar surface

Before inhalation ...... _____ is equal to _____ and there is no air movement what does Patm and Palv equal? what is the relation between the two?

Patm is equal to P alv and there is no air movement Patm and Palv = 0 Patm=Palv

what does boyle's law state?

boyle's law states that at a constant temp, the pressure of a gas varies inversely with its volume P1V1=P2V2

during exhalations what relaxes? the diaphragm and chest wall are no longer actively pulled outward by muscle contractions, so they start to recoil inward, (increasing/decreasing) the size of the ___________ to its original smaller size

during exhalation, diaphragm and intercostal muscles relax the diaphragm and chest wall are no longer actively pulled outward by muscle contractions, so they start to recoil inward, decreasing the size of the thoracic cavity to its original smaller size

during inhalation, the diaphragm moves _______ into the abdomen, enlarging the ______ intercostal muscles contract, leading to upward and outward movement of the ribs further actively (increasing/decreasing) the size of the __________

during inhalation, the diphragm moves downward into the abdomen, enlarging the thorax intercostal muscles contract, leading to upward and outward movement of the ribs further actively increasing the size of the thorax

what else does lung volume depend on?

how stretchable the lungs are, which determines how much they expand at a given change in transpulmonary pressure

surfactant (lowers/highers) the surface tension, which increases _________, and makes it easier to _____ the lungs

since surfactant lowers the surface tension, which increases lung compliance, and makes it easier to expand the lungs

the Law of LaPlace describes the relationship between _______, _______, and ________ formula? the alveoli can be stabilized by -

the Law of LaPlace describes the relationship between pressure (P), surface tension (T), and radius of the curved surface (r) P= 2T/r the alveoli can be stabilized by altering surface tension

what does lung volume depend on?

the difference in pressure inside and outside of the lung. this is called the transpulmonary pressure (P tp)

the type _____ alveolar cells secrete the detergent-like substance known as _____

the type II alveolar cells secrete a detergent-like substance known as surfactant

do muscles pull lungs open or push them shut?

there are no muscles attached to the lungs to pull them open or push them shut

during inhalation..... 1. _____ and _____ contract 2. ______ expands 3. ___________ becomes more subatmospheric 4. (increase/decrease) in transpulmonary pressure 5. _______ expands 6. ______ becomes subatmoshperic 7. air flows into the ________

1. diaphragm and intercostals contract 2. thorax expands 3. P ip becomes more subatmospheric 4. increase in transpulmonary pressure 5. lungs expand 6. P alv becomes subatmospheric 7. air flows into the alveoli

during inhalation- 1. _____ and _____ contract 2. ______ expands 3. ________ becomes more negative (_________) 4. ______ pressure increases 5. ______ expand *increased thoracic volume results in increased ________ and decreased ______ what does Palv equal?

1. diaphragm and intercostals contract 2. thorax expands 3. intrapleural pressure becomes more negative (subatmospheric) 4. transpulmonary pressure increases 5. lungs expand *increased thoracic volume results in increased alveolar volume and decreased alveolar pressure Palv= -1

during exhalation ...... 1. _____ and _____ stop contracting 2. _______ recruits inward 3. ______ moves back toward preinspiration value 4. ________ moves back toward preinspiration value 5. _______ recoil toward preinspiration size 6. air in alveoli becomes _______ 7. _____ becomes greater than ______ 8. air flows _____

1. diaphragm and intercostals stop contracting 2. chest wall recruits inward 3. P ip moves back toward preinspiration value 4. Transpulmonary pressure moves back toward preinspiration value 5. lungs recoil toward preinspiration size 6. air in alveoli becomes compressed 7. P alv becomes greater than P atm 8. air flows out of the lungs

exhalation - 1. _____ and _____ muscles relax 2. _____ recoils inward 3. ______ pressure moves back toward ________ value 4. _________ pressure moves back toward _______ 6. _______ recoils to _______ size *_________ thoracic volume results in _______ alveolar volume and _______ alveolar pressure what does Palv=?

1. diphragm and intercostals relax 2. chest wall recoils inward 3. intrapleural pressure moves back toward pre-inhalation value 4. transpulmonary pressure moves back toward pre-inhalation value 5. lung recoils to pre-inhalation size * decreased thoracic volume results in decreased thoracic alveolar volume and increased alveolar pressure Palv=1 (alveolar volume decreases)

during inhalation - 1. _______ expand 2. _______ becomes more negative (______) 3. air flows into the ________ ________ pressure is greater than ______, and air moves into the lungs (from _____ pressure to ______ pressure) what does Patm equal? relation between Patm and Palv?

1. lungs expand 2. alveolar pressure becomes more negative (subatmospheric) 3. air flows into the alveoli *atmospheric pressure is greater than alveolar pressure, and air moves into the lungs (from higher pressure to lower pressure) Patm=0 Patm > Palv

summary : breathing 1. muscles of the _______ contract 2. _______ expands during inspiration 3. simultaneously, the ______ contracts downward, , further enlarging the _________ 4. volume of the thoracic cavity _________, _____ decreases 5. ______ becomes more positive and ______ expand 6. ______ becomes more negative than ______ and air flows inward 7. _____ increases to fill the lungs with air by ________ the pressure surrounding the ______ (____) relative to the pressure _______ the lungs (____) 8. when the respiratory muscles relax, ________ of the lungs drives passive ________ back to the starting point

1. muscles of the chest wall contract 2. chest wall expands during inspiration 3. simultaneously, the diaphragm contracts downward, further enlarging the thoracic cavity 4. volume of the thoracic cavity increases, P ip decreases 5. Pip becomes more positive, and lungs expand 6. P alv becomes more negaitve than P atm, and air flows inward 7. Pip increases to fill the lungs with air by decreasing the pressure surrounding the lungs (Pip)relative to the pressure inside the lungs (Palv) 8. when respiratory muscles relax, recoil of the lungs drives passive expiration back to the starting point

lung compliance - compliance can be considered the inverse of _______ the greater the compliance , the easier it is to - what is lung compliance determined by? (2)

compliance can be considered the inverse of stifness the greater the compliance, the easier it is to expand the lungs at any given change in transpulmonary pressure lung compliance determined by- 1. the stretch ability of the elastic fibers in lung tissues 2. the surface tension of the fluid that lines the alveoli

physics and gases: gases ______ their container when gas molecules are far apart, their pressure is _______ when gas molecules are close together, their pressure is _____

gases fill their container when gas molecules are far apart, their pressure is low when gas molecules are close together, their pressure is high

end of inhalation - is lung size changing? which pressures are equal to eachother? is there airflow? what does Patm and Palv equal?

lung size is not changing and the airway is open to the atmosphere P alv = P atm there is no airflow Patm =0 / Palv=0

the law of LaPlace - _____ is proportiontional to _____ so alveolus a would have a ____ pressure than alveolus b by the _______ the smaller radius alveolus (___) would collapse into the ________ (__) that had ______ pressure *refer to diagram on powerpoint

pressure is proportional to 1/r , so alveolus a woud have a lower pressure than alvelous b by the law of laplace the smaller radius alveolus (b) would collapse into the larger radius alveolus (a) that had lower pressure