Module 2.2: Respiratory Physiology

Question 1

Pressure Equation

Answer 1

P=F/A
Force per unit area (cmH2O)

Question 2

Flow

Answer 2

Quantity of gas that moves throughout a given area (ml/sec, L/s)

Question 3

Volume

Answer 3

-Amount of air contained in a vessel of space (ml, L)
-In enclosed space, volume and pressure are inversely related
-↑ Volume, ↓ Pressure
-Boyles law in respiration: Pressure increases when volume decreases

Question 4

Lungs-Thoracic Unit

Answer 4

-Movement of rib cage wall and diaphragm translated to lung movement via pleural linkage
-Lungs alone: collapse in
-Thorax alone: spring out
-Due to connection, lungs are slightly expanded and thorax slightly compress

Question 5

Lungs- Thoracic Unit and Inhalation

Answer 5

-Increase in thoracic cavity size -> increase in lung volume
-Fewer air particles colliding due to larger space
-Decrease in lung pressure
-Air rushes in (to region of lower pressure)

Question 6

Lungs-Thoracic Unit and Exhalation

Answer 6

-Decrease in thoracic cavity size -> decrease in lung volume
-More air particles colliding due to smaller space
-Increase in lung pressure
-Air rushes out (to region of lower pressure)

Question 7

Lungs-Thoracic Unit and Resting Expiratory Level (REL) or Resting Level (RL)

Answer 7

-Balanced State
-Forces of lungs wanting to collapse and thorax wanting to expand are equal and opposite
-Pressure of alveoli=Pressure of atmosphere
-Start and end of each breath

Question 8

Tidal Volume (TV)

Answer 8

Amount of air inhaled or exhaled during resting breathing

Question 9

Inspiratory Reserve Volume (IRV)

Answer 9

Max amount of air that can be inhaled from end-inspiratory level

Question 10

Expiratory Reserve Volume (ERV)

Answer 10

Max amount of air that can be exhaled from end-expiratory level

Question 11

Residual Volume

Answer 11

Amount of air remaining in the lungs after max exhalation

Question 12

Vital Capacity (VC)

Answer 12

max amount of air that can be exhaled after max inhalation (IRV + TV + ERV)

Question 13

Total Lung Capacity (TLC)

Answer 13

Volume of air in lungs and airways after max inhalation (IRV+TV+ERV+RV)

Question 14

Respiration involves active and passive forces

Answer 14

-Active: muscle forces
-Passive: elastic recoil of lung-thoracic unit, torque, gravity

Question 15

Inhalation Forces

Answer 15

-Active forces always required to increase volume size if starting at resting level
-Passive forces if below resting level

Question 16

Exhalation Forces

Answer 16

-Passive during resting breathing
-Passive + active forceful exhalation
-Passive + active during speech

Question 17

Forces in Speech

Answer 17

-Between 40-60% VC
-Requires ≥7 cm H2O positive lung pressure
-Requires forces provide positive pressure above RL, but <7 cmH2O between 40-60% VC
-Must add active expiratory forces

Question 18

Speech Breathing vs. Resting Breathing

Answer 18

-Faster inhalation, prolonged exhalation
-Speech usually produced above RL
-Take advantage of passive recoil forces
-Less expiratory muscle effort needed
-Respiratory apparatus stiffer at high and low lung volumes
-Volume displacement greater than for resting breathing
-40-60% VC vs. 50-40% VC
-Abdominal muscles stay active in inhalation and exhalation = mechanical tuning

Question 19

Connected Speech

Answer 19

-Rapid change state
-Pressure and air flow never constant
-Average of 7 cmH2O needed
-Changes depend on:
-Phonetic factors
-Prosodic factors
-Speaking task
-Pulsatile changes for:
-Intonation and stress patterns
-Varying loudness
-Different consonant pressures