Respiratory - Pt 3 Control of Respiration

Question 1

CO₂ + [] <–> H₂CO₃ <–> H₊ + []

What enzyme catalyzes the left side of this equation?

Answer 1

H₂O; HCO₃^-

Carbonic Anhydrase

Question 2

90% of the CO₂ in our bodies moves around as []

Answer 2

HCO₃^-

Question 3

Peripheral Chemoreceptors detect concentration changes in which molecules?

Answer 3

Oxygen, CO₂, pH (H⁺)

Question 4

The body is much more sensitive to [] concentrations than [] concentrations.

Answer 4

CO₂; Oxygen

Question 5

What are the 4 components, in the brain stem, for controlling breathing?

Answer 5

Chemoreceptors for O2, CO2, and H+

Mechanoreceptors in teh lungs and joints

Control centers in the medulla and pons

Respiratory muscles

Question 6

The pontine respiratory group (PRG) plays the main role in modulating respiration. What are the 2 parts to the PRG and what does each do?

Answer 6

• Apneustic center: drives inspiration and can prolong inspiration by prolonging the period of action potentials in the phrenic nerve.
• Pneumotaxic Center: fine tunes the switch between inspiration and expiration and can limit action potentials sent down the phrenic nerve.

Question 7

Apneustic center: drives [] and can prolong inspiration by [] the period of [] [] in the phrenic nerve.

Answer 7

Apneustic center: drives inspiration and can prolong inspiration by prolonging the period of action potentials in the phrenic nerve.

Question 8

Pneumotaxic Center: fine tunes the switch between [] and [] and can limit action potentials sent down the [] nerve.

Answer 8

Pneumotaxic Center: fine tunes the switch between inspiration and expiration and can limit action potentials sent down the phrenic nerve.

Question 9

T/F

CO₂ and O₂ concentrations are monitored by central chemoreceptors?

Answer 9

FALSE

Only Blood CO₂ levels, and interstitial H⁺, are monitroed by central chemoreceptors.

Question 10

T/F

Central chemoreceptors indirectly sense the blood H⁺ concentrations?

Answer 10

FALSE

Central chemoreceptors indirectly sense the interstitial H⁺ levels.

Question 11

Decreases in the pH of CSF produce [] in breathing rate ([] , and increases in the pH of CSF produce [] in breating rate ([] ).

Answer 11

Decreases in the pH of CSF produce increases in breathing rate (hyperventilation), and increases in the pH of CSF produce decreases in breating rate (hypoventilation).

Question 12

How do central chemoreceptors indirectly monitor H+ levles?

Answer 12

• H+ does not cross the blood brain barrier. However, CO₂ does.
• So when the P_CO2 increases in the arteries, the P_CO2 will increase in the CSF. In the CSF CO₂ will convert to H+ and HCO₃^-…thus increasing the levels of H+ in the CSF.
• The chemoreceptors would detect this change and increase breathing rate to raise pH levels.

Question 13

Each of the following are detected by peripheral chemoreceptors and produces an increase in breathing rate:

• [] in arterial PO₂
• [] in arterial PCO₂
• [] in arterial pH

Answer 13

• decrease in arterial PO₂
• increase in arterial PCO₂
• increase in arterial pH

Question 14

Ventral respiratory group (VRG): contain [] generators whose otuput drives [].

Answer 14

Ventral respiratory group (VRG): contain rhythm generators whose otuput drives respiration.

Question 15

The Dorsal Respiratory group (DRG) could also be called the respiratory []. It integrates and modifies rhythms generated by the [].

Answer 15

The Dorsal Respiratory group (DRG) could also be called the respiratory control center. It integrates and modifies rhythms generated by the VRG.

Question 16

What 2 “groups” in the medulla control breathing? Which one actually initiates the response in breathing? (bolded on the backside of card)

Answer 16

Ventral respiratory group (VRG)

Dorsal respiratory group (DRG)

Question 17

The [] and [] [] [] send their signal to the DRG which then control the rhythms genreated by the []

Answer 17

• chemoreceptors
• Pontine respiratory group
• VRG

Question 18

What 3 factors influence breathing rate and depth?

Answer 18

1. Pulmonary irritant reflexes
2. Lung stretch Receptors
3. Chemical Factors

Question 19

Pulmonary Irritant reflexes

• Locted between [] cells lining airways and send info to medulla via the [] [] (cranial 10)
• Cause a reflex [] of bronchial smooth muscle and an [] in breathing rate.

Answer 19

• Located between epithelial cells lining airways and send info to medulla via the vagus nerve (cranial 10)
• Cause a reflex constriction of bronchial smooth muscle and an increase in breathing rate.

Question 20

Lung Stretch Receptors:

1. [] present in the smooth muscle of the airways
2. stimualted by [] of the lungs and airways
3. initiate a reflex [] in breathing rate called [] reflex
4. Decreases breathing rate by prolonging [].

Answer 20

1. Mechanoreceptors present in the smooth muscle of the airways
2. stimulated by distention of the lungs and airways
3. initiate a reflex decrease in breathing rate called Hering-Breur reflex
4. Decreases breathing rate by prolonging expiratory time.

Question 21

Chemical factors that influence breathing rate:

• Increased CO₂ (hypercapnia) causes a [] in pH
• This stimulates []

Answer 21

• Increased CO₂ (hypercapnia) causes a decrease in pH
• This stimulates hyperventilation

Question 22

What is the airflow equation? What does each variable represent?

Answer 22

V = (delta)P/R

• V = airflow (L/min)
• (delta)P = Pressure gradient (mmHG)
• R - AIrway resistance

Question 23

V (airflow) and resistance are [] related.

Answer 23

V (airflow) and resistance are inversely related.

Question 24

What are the 3 physical factors influencing pulmonary ventilation?

Answer 24

1. Airway resistance
2. Alveolar surface tension
3. Lung Compliance

Question 25

1. If airway resistance decreases…what happens to airflow?
2. If alveolar surface tension increases….what happens ot airflow?

Answer 25

1. airflow increases
2. airflow decreases

Question 26

[] is the major non elastic source of resistance to gas flow

Answer 26

friction

Question 27

What is the equation for the Law of LaPlace?

What does each variable stand for?

Answer 27

P = 2T/r

• P - collapsing pressure on alveolus
• T - surface tension
• r - radius of alveolus

Question 28

T/F

The 2T/r portion of Law of LaPlace can be thought of as the pressure required to keep the alveolus open.

Answer 28

True!

Question 29

Surface tension:

Resists an force that tends to [] the sruface area of the liquid.

Answer 29

increase

Question 30

T/F

Surfactant is more useful in large alveoli and not small alveoli?

Answer 30

FALSE

Small alveoli are close together which increases the effects of surface tension. So these smaller alveoli need surfactant moreso than larger ones.

Question 31

Lung Compliance: a measure of the change in lung [] that occurs with a given change in [] pressure

Answer 31

Volume

transpulmonary

Question 32

Lung Compliance:

• Normally high due to
  
  • [] of the lung tissue
  • [] alveolar surface tension
• Diminished by
  
  • []-[] scar tissue (fibrosis)
  • Reduced production of []
  • Decreased [] of the thoracic cage

Answer 32

• Normally high due to
  
  • Distensibility of the lung tissue
  • Decreased alveolar surface tension
• Diminished by
  
  • Non-elastic scar tissue (fibrosis)
  • Reduced production of surfactant
  • Decreased flexibility of the thoracic cage

Question 33

Increasing lung compliance [] the collapsing force at any given volume so that it is [] for the lungs to expand.

Answer 33

Reduces

Easier

Question 34

T/F

The lungs are less compliant at the base of the lung relative to the apex of the lung.

Answer 34

FALSE

The apex of the lung is already stretched, we know this, so it would make sense that the base of the lung has more “stretchyness” available to it.

Question 35

[] [] [] is the volume of inspired air in the conducting zone conduits. It is roughly [] mL

Answer 35

Anatomical Dead Space

150mL

Question 36

Functional Dead Space is when alveoli cease to act in [] [] due to collapse or obstruction or []/[] mismatch.

Answer 36

Functional Dead Space is when alveoli cease to act in gas exchange due to collapse or obstruction or ventilation/perfusion mismatch.

Question 37

T/F

Of the 500mL of air that are exchanged through Tidal Volume, only rougly 150mL of that air actually reach the alveoli for gas exchange.

Answer 37

FALSE

only about 350 mL of air reach the alveoli. 150 mL stay inside the anatomical dead space.

Question 38

T/F

For someone with emphysema, it is easier to inspire and harder to expire.

Answer 38

TRUE

Question 39

Some suffering from emphysema would experience a [] FRC.

Answer 39

larger

Question 40

Somone suffering from pulmonary fibrosis (or a [] disease) would experience difficulty [] and a [] FRC and Total Lung Capacity.

Answer 40

Somone suffering from pulmonary fibrosis (or a restrictive disease) would experience difficulty inhaling and a lower FRC and Total Lung Capacity.

Question 41

T/F

Somone suffering from astma/Emphysema and Pulmonary Fibrosis would have a lower FEv₁ than normal individuals.

Answer 41

TRUE.

Question 42

Someone suffering from a restrictive disease would be able to exhale []-[]% of their [] within 1 second of exhaling.

Answer 42

Someone suffering from a restrictive disease would be able to exhale 90-95% of the FVC within 1 second of exhaling.

Question 43

Which individual is able to expire more of their FVC within the first second of exhaling…

1. Normal Individual
2. Individual suffering from an obstructive disease
3. Individual suffering from a restrictive disease

Answer 43

3. Individual suffering from a restrictive disease

These people can blow off 90-95% of their FVC