Ventilation Responses

Question 1

pp O2 is … in arteries at rest
tissue capillary is,…
Reason for alteration in Po2 is …

PP of O2 in the arteries … because … offsets the increase in oxygen usage

what happens to s shaped curve during exercise and rest

where does the Haldane effect happen
BOHR?

Because there is little movement at rest, so … factors control respiration at …

A variety of … affect ventilation: - happens during …

… ARE PRIMARY AT REST

AT REST, … IS SECONDARY

Answer 1

100
40
increase oxygen extraction

is maintained at 100 becuase of increased ventilation

exercsie shifts right
rest shifts left

lungs
muscle

Because there is little movement at rest, so humoral factors control respiration at rest - no proprio/mechano receptors, no motor cortex

A variety of neural inputs affect ventilation: - happens during EXERCISE

HUMORAL FACTORS ARE PRIMARY AT REST

AT REST, NEURAL IS SECONDARY

Question 2

However, respiratory function is very sensitive to psychological factors at rest
e.g. stress responses

• I: Anticipation (…)
• II: Exponential (…)
• III: Steady-state (…)
• Recovery: (… first, … second)

Answer 2

However, respiratory function is very sensitive to psychological factors at rest
e.g. stress responses

• I: Anticipation (Neural)
• II: Exponential (Neural and humoral)
• III: Steady-state (Neural and humoral)
• Recovery: (Neural first, Humoral second)

Question 3

• The partial pressure of O2 determines …, which characterizes the …;
• The majority of O2 is transported bound to …;
• Exercise increases muscle oxygen uptake, which leads to a greater …; and

The oxygen dissociation curve
* Hemoglobin is not always 100% saturated with oxygen
* Arterial PO2 (Pa O2) determines … (… O2)
* The percentage of hemoglobin that is bound to oxygen
* ~98% at sea-level
* Maybe a little lower in Calgary
* The relationship between Pa O2 and Sa O2 is “S-shaped”
* Increased O2 availability increases the affinity of hemoglobin for O2

Answer 3

• The partial pressure of O2 determines O2 saturation, which characterizes the O2 content of blood;
• The majority of O2 is transported bound to hemoglobin;
• Exercise increases muscle oxygen uptake, which leads to a greater arteriovenous oxygen difference; and

The oxygen dissociation curve
* Hemoglobin is not always 100% saturated with oxygen
* Arterial PO2 (Pa O2) determines arterial saturation (Sa O2)
* The percentage of hemoglobin that is bound to oxygen
* ~98% at sea-level
* Maybe a little lower in Calgary
* The relationship between Pa O2 and Sa O2 is “S-shaped”
* Increased O2 availability increases the affinity of hemoglobin for O2

Question 4

Oxygen dissociation curve (Arterial vs. venous)

Sigmoid (S-shaped) curve → cooperative binding
Arterial blood (PO₂ ~100 mmHg) → ~98–100% saturated
Venous blood (PO₂ ~40 mmHg) → ~75% saturated
~25% O₂ delivered to tissues at rest
Plateau (top) → lungs → easy O₂ loading
Steep part (middle) → tissues → easy O₂ unloading
High PO₂ → O₂ binds hemoglobin
Low PO₂ → O₂ released to tissues

Question 5

Oxygen dissociation curve (Shifting)

Factors affecting the affinity of hemoglobin for oxygen

Left shift (… effect): … “…”
* … pH (… acidity)
* … temperature
* … CO2

Right shift (… effect): … oxygen “…”
* … pH (… acidity)
* … temperature
* … CO2 - ……….

Answer 5

Oxygen dissociation curve (Shifting)

Factors affecting the affinity of hemoglobin for oxygen

Left shift (Haldane effect): Bind oxygen “tighter”
* Increased pH (decreased acidity)
* Decreased temperature
* Decreased CO2

Right shift (Bohr effect): Bind oxygen “looser”
* Decreased pH (increased acidity)
* Increased temperature
* Increased CO2 - at the level of the muscle

Question 6

Ventilatory control

• Ventilation is regulated by … and … factors
• Act on …
• … sent to respiratory muscles
• Regulation is … at rest and during exercise

Answer 6

Ventilatory control

• Ventilation is regulated by neural and humoral factors
• Act on respiratory center
• Action potentials sent to respiratory muscles
• Regulation is different at rest and during exercise

Question 7

A variety of … inputs affect ventilation: - happens during …

Related to movement
* … (voluntary movements)
* …in lungs and airway (…ceptors)
* …ceptors in …, …, …

Intrinsic firing of the respiratory center
* …
* …

Neural factors play a significant role in the regulation of … responses during …

Because there is little movement at rest, so ……… factors control respiration at rest

• However, respiratory function is very sensitive to psychological factor at rest (e.g., stress response due to ………… and activation of sympathetic pathway)

Answer 7

A variety of neural inputs affect ventilation: - happens during EXERCISE

Related to movement
* Motor cortex (voluntary movements)
* Stretch receptors in lungs and airway (mechanoreceptors)
* Proprioceptors in muscles, joints, tendons

Intrinsic firing of the respiratory center
* Fight or flight situation
* Emotional status

Neural factors play a significant role in the regulation of cardiorespiratory responses during exercise

Because there is little movement at rest, so humoral factors control respiration at rest - SINCE THESE ARE NEURAL FACTORS, AND THERE ISNT MUCH AT REST, HUMORAL FACTORS TAKE OVER

• However, respiratory function is very sensitive to psychological factor at rest (e.g., stress response due to withdrawal of vagal tone and activation of sympathetic pathway)

Question 8

… factors

Central chemoreceptors
* In the …, responds to … and …

Peripheral chemoreceptors
* In …, respond to …, …, and …
* Monitors … blood

Pa … and … play a significant role in respiratory function at rest, however:

• … (…) is a neural factor to maintain low HR at rest;

Increase in … and … also play a considerable role in cardiorespiratory responses during exercise

Answer 8

Humoral factors

Central chemoreceptors
* In the medulla, responds to ↓pH and ↑CO2

Peripheral chemoreceptors
* In aortic/carotid bodies, respond to ↓PO 2, ↑CO2, and ↓pH
* Monitors arterial blood

Pa CO2 and H+ play a significant role in respiratory function at rest, however:

• Vagal tone (NEURAL) is a neural factor to maintain low HR at rest;

Increase in PaCO2 and H+ also play a considerable role in cardiorespiratory responses during exercise

Question 9

Phases of ventilation in response to constant-load exercise

Rest: … and … play a significant role in cardiorespiratory function at rest

Respiratory function is very sensitive to … factors at rest
e.g. … responses

• I: Anticipation (…)
• II: Exponential (…)
• III: Steady-state (…)
• Recovery: (… first, … second)
• … factors play a significant role in the regulation of cardiorespiratory responses during exercise
• Increase of … and … plays a significant role in CR during exercise

Answer 9

Phases of ventilation in response to constant-load exercise

Rest: PaCO2 and H+ play a significant role in cardiorespiratory function at rest - HUMORAL

Respiratory function is very sensitive to psychological factors at rest
e.g. stress responses

• I: Anticipation (Neural)
• II: Exponential (Neural and humoral)
• III: Steady-state (Neural and humoral)
• Recovery: (Neural first, Humoral second)
• NEURAL factors play a significant role in the regulation of cardiorespiratory responses during exercise
• Increase of PaCO2 and H+ plays a significant role in CR during exercise

Question 10

Does ventilation limit performance?

• In untrained individuals, the respiratory system is “…” for exercise
• It … of the cardiovascular and skeletal muscle systems
• Training has … system
• … factor for performance

TRAINED: with huge mitochondrial content in the muscles and lots of cappilaries
they can extract all of the oxygen they need to, muscles are not the limiting factor, they can get better

peoples heart and lungs fall behind, they can not get as well adapted

Answer 10

Does ventilation limit performance?

• In untrained individuals, the respiratory system is “over built” for exercise
• It exceeds the capacity of the cardiovascular and skeletal muscle systems
• Training has little effect on the respiratory system
• Lungs become a limiting factor for performance

Question 11

Summary

• The majority of CO2 in blood is transported as …;
• The binding of O2 to Hb promotes …;
• The lungs help buffer … changes in blood by removing …;
• … factors primarily regulate ventilation at rest;
• … factors primarily regulate ventilation during exercise; and
• The … may limit performance in well trained individuals.
• Bohr effect: The increases in the … of blood or decreases in blood … result in a … affinity of hemoglobin for …
• Haldane effect: The … ability to influence the affinity of hemoglobin for CO2 and H +.
  This effect promotes the … of … from the tissues to the blood and stimulates the release of … … from the blood to the lungs.

Answer 11

Summary

• The majority of CO2 in blood is transported as bicarbonate.
• The binding of O2 to Hb promotes CO2 and H+ release;
• The lungs help buffer pH changes in blood by removing CO2;
• Humoral factors primarily regulate ventilation at rest;
• Neural factors primarily regulate ventilation during exercise, and
• The respiratory system may limit performance in well trained individuals.
• Bohr effect: The increases in the CO2 partial pressure of blood or decreases in blood pH result in a lower affinity of hemoglobin for oxygen
• Haldane effect: The oxygen’s ability to influence the affinity of hemoglobin for CO2 and H +.
  This effect promotes the release of CO2 from the tissues to the blood and stimulates the release of carbon dioxide from the blood to the lungs.