Lecture 30 Flashcards by ShinHae Yoon

______ is the exchange of air between the atmosphere and the lungs where gas exchange with the blood occurs.

Ventilation

How well did you know this?

Not at all

Perfectly

_________ requires that P-alv < P-atm, (negative value), so air flows in.

Inhalation

How well did you know this?

Not at all

Perfectly

__________ requires that P-alv > P-atm, (positive value), so air flows out.

Exhalation

How well did you know this?

Not at all

Perfectly

Actual air flow is also dependent on the resistance of the airways to flow which is primarily due to airway _______ which is affected by the ANS.

diameter

How well did you know this?

Not at all

Perfectly

Inflation/deflation of the lungs is due to _______ vs compliance (“stretchability”)

transpulmonary pressure (Ptp)

How well did you know this?

Not at all

Perfectly

The _______ is the pressure difference between the alveoli and the intrapleural fluid and is defined as Palv - Pip

transmural pulmonary pressure (Ptp)

How well did you know this?

Not at all

Perfectly

The _______ is the pressure difference between the intrapleural fluid and the atmosphere and is defined as Pip - Patm

transmural chest wall pulmonary pressure (Pcw)

How well did you know this?

Not at all

Perfectly

Overall, the ________ is the pressure difference between the alveoli and the atmosphere and is defined as Palv - Patm: combination of Ptp and Pcw

transmural respiratory system pressure (Prs)

How well did you know this?

Not at all

Perfectly

Ptp is a determinant of _____ and Prs determines _____ (ignoring R/resistance to flow/airway diameter)

lung size; flow

How well did you know this?

Not at all

Perfectly

_______ requires muscle contraction to ↑volume of thorax causing ↓Pip/more negative.

Inspiration

How well did you know this?

Not at all

Perfectly

Ptp becomes more positive, it means the lungs are ______

expanding

How well did you know this?

Not at all

Perfectly

T or F?During inspiration various muscles contract to ↑volume of thorax and therefore ↓Pip.

True

How well did you know this?

Not at all

Perfectly

What is tidal volume (TV)?

Amount of air inhaled or exhaled in one breath during relaxed, quiet breathing. (~500mlml)

How well did you know this?

Not at all

Perfectly

What is inspiratory reserve volume (IRV)?

Amount of air in excess of tidal inspiration that can be inhaled with maximum effort. (~3200ml)

How well did you know this?

Not at all

Perfectly

What is expiratory reserve volume (EVR)?

Amount of air in excess of tidal inspiration that can be exhaled with maximum effort. (~1200ml)

How well did you know this?

Not at all

Perfectly

What is residual volume (RV)?

Amount of air remaining in the lungs after maximum expiration; keeps alveoli inflated between breaths and mixes with fresh air on next inspiration. (~1200ml)

What is vital capacity (VC)?

Amount of air that can be exhaled with maximum effort after maximum inspiration (ERV+TV+IRV); used to assess strength of thoracic muscles as well as pulmonary function. (~4700ml)

What is inspiration capacity (IC)?

Maximum amount of air that can be inhaled after a normal tidal expiration (TV+IRV). (~3500ml)

What is functional residual capacity (FRC)?

Amount of air remaining in the lungs after a normal tidal expiration (RV+ERV). (~2400ml)

What is total lung capacity (TLC)?

Maximum amount of air the lungs can contain (RV+VC). (~5900ml)

How is flow rate of air calculated?

F = (Palv-Patm)/R

What is the pressure difference between breaths?

Difference is 0mmHg (Pressue is at 760mmHg)

During expiration, is the diaphragm contracted or relaxed?

Relaxed

During inpiration, is the intercostal muscles contracted or relaxed?

Contracted

T or F? During normal/gentle/tidal breathing, no active muscle contraction are involved.

True

During "forced" inspiration, what muscles are involved?

External intercostals plus the scalenes, sternocleidomastoid and pectoralis minor causing an even greater ↑volume. (Rib cage is moved upward and outward.

During "forced" expiration, what muscles are involved?

Oblique and transversus abdominis muscles plus the internal intercostals actively pull the ribs down and inwards, (latissimus dorsi also), decreasing volume.

What are the 2 determinants of lung compliance?

Elasticity of the lungs and the effect of surface tension (of water molecules).

What are secreted by septal (type 2) cells and what is the purpose?

Surfactant. It is a complex of phospholipids, lipids, and proteins which form a monolayer at the air-water interface and ↓attraction between the water molecules like a detergent. (Prevents H2O from contracting)

What factors affect airway resistance?

Airway length, airway radius, and interactions with moving gas molecules

How does the ANS affect the airway diameter?

Adrenaline dilates via Beta-2 | Acetylcholine constricts via M3/muscarinic

During inflammation, produced in the lungs are leukotrienes and eicosanoids, what effects do they have on airway diameter?

The will cause constriction

What must be considered when measuring lung volume in a laboratory?

Correction of temperature (body is 37 degrees) Dry lab air vs Water vapor pressure in body (47mmHg) Spirometers have now been largely replaced with transducers that do not have large dead spaces prone to collect water and limit flow or accumulate CO2 which stimulates breathing

______ is the percentage of the vital capacity that can be forcefully exhaled in one second and this gives a good indication of airway resistance.

FEV1 (Forced Expiratory Volume)

What is the driving force for breathing?

CO2 and the pH.

What needs to be subtracted from the minute ventilation to give a true estimate of the volume of air reaching the alveoli?

Anatomical dead space. Minute ventilation = (tidal volume - anatomical dead space volume) x frequency)

What is the Po2 around the aveoli?

Po2 = 100mmHg

What is the Pco2 around the aveoli?

Pco2 = 40mmHg

T or F? During Tidal volume, ~350ml/breath reaches the aveoli.

True. Anatomical dead space should be subtracted from the minute ventilation to give a true estimate of the volume of air reaching the alveoli: minute ventilation = (tidal volume - anatomical dead space volume) x frequency; now this is reduced to 4200mL/min