EPHE 441 LAB PRACTICAL EXAM WITH COMPLETE
VERIFIED SOLUTIONS!!
Lab 1
Describe the effect of pH on the O2-Hb Dissociation Curve
- Shifts to the left when pH goes up
- Shifts to right when pH goes down
- Affinity for hemoglobin to bind oxygen decreases
- Decrease in pH weakens strength on the bond between Hb and O
- Results in unloading of O2 to the tissues and a right shift in the curve (Bohr effect)
- Rise in blood H+ ion levels during intensity exercise
- H+ binds to Hb, which prevents O2 from binding (decrease Hb affinity for binding O2)
- During glycolysis pyruvate molecules can accept H+ to make lactate
- Also NAD+ can form NADH to take away some of these H+ ions
Describe the effect of temperature on the O2-Hb dissociation curve
- increase in temperature causes a right shift in the curve (weakens the bond between
O2 and Hb, favors unloading of O2 to muscle)
- occurs during exercise
- decrease in temperature causes a left shift in the curve (hinders O2 release to muscle)
Describe the role of 2-3 DPG on the O2-Hb dissociation curve
2-3 DPG affects the position of the oxygen dissociation curve. If there is a decrease in
2-3 DPG within the red blood cells, the oxygen dissociation curve favours the left. If
there is an increase in 2-3 DPG within the red blood cells the oxygen dissociation curve
,favours the right. Red blood cells are special in that they do not have a nucleus or
mitochondria, meaning they must rely on anaerobic glycolysis to meet the cells' energy
needs. A by-product of RBC glycolysis is the compound 2-3 DPG. This combined with
hemoglobin will reduce Hb's affinity for oxygen, thus causing a right shift on the oxygen
dissociation curve.
RBC concentrations of 2-3 DPG increase during exposure to altitude and anemia. This
means that the right shift in the oxyhemoglobin curve that occurs during heavy exercise
is not due to changes in 2-3 DPG, but to the degree of acidosis and blood temperature
elevation.
Describe the role of ventilation in regulating the acid-base balance of blood
In the case of decreased blood pH (increased free H+ ions in the blood), the CO2
carbonic anhydrase reaction shifts in favour of exhaling Co2. The body responds by
increasing the rate and depth of respiration to return to a pH of 7.35-7.45.
In the case of respiratory alkalosis (increase in pH due to decrease in H+), the CO2
carbonic anhydrase reaction will shift in the opposite direction towards H+ and CO2 in
order to maintain homeostasis. Ventilation will decrease.
Use the concept of the 02-Hb dissociation curve to explain fatigue (exercise capacity is
limited)
During high intensity exercise, changes in the O2-HB dissociation curve are evident and
can be used to explain the onset of fatigue. Beginning with the primary factor of pH, high
intensity exercise sees an increase in H+ ions within the blood, preventing oxygen
binding to hemoglobin and thus affecting muscular endurance. As well, lactate can form
by accepting these H+ ions. Temperature increases during exercise can also cause
fatigue, by weakening the bonds between O2 and hemoglobin. Ventilation and 2,3-dpg
can also affect it.
Increased pH and thus decreased H+ ions will impact the capacity of ventilation via
carbonic anhydrase. 2-3 DPG increases (byproduct of red blood glycolysis) and reduces
the affinity of Hb for oxygen (rightward shift, causing acidosis and blood temp elevation,
and thus changes from first submission).
, Lab 2
The term "maximal oxygen uptake" was coined and defined by Hill et al. and Herbst in
what decade? The answer contains only a four-digit number.
1920
Which of the following statements is false regarding the VO2max paradigm of Hill &
Lupton (1923)?
a) A high VO2max is a prerequisite for success in middle- and long-distance running.
b) VO2max is limited by ability of the cardiorespiratory system to transportterm-16 O2 to
the muscles.
c) There is not an upper limit to oxygen uptake.
d) There are interindividual differences in VO2max.
c) There is not an upper limit to oxygen uptake.
Not all subjects show a plateau in VO2 at the end of a graded exercise test (GXT), when
graphed against work intensity. It has repeatedly been shown that about what % of
subjects do not demonstrate a plateau when stressed to maximal effort? The answer
contains only a two-digit number.
50
Because not all participants achieve a plateau in VO2max with increasing workloads, it
is recommended that secondary criteria be applied to verify maximal effort. These
VERIFIED SOLUTIONS!!
Lab 1
Describe the effect of pH on the O2-Hb Dissociation Curve
- Shifts to the left when pH goes up
- Shifts to right when pH goes down
- Affinity for hemoglobin to bind oxygen decreases
- Decrease in pH weakens strength on the bond between Hb and O
- Results in unloading of O2 to the tissues and a right shift in the curve (Bohr effect)
- Rise in blood H+ ion levels during intensity exercise
- H+ binds to Hb, which prevents O2 from binding (decrease Hb affinity for binding O2)
- During glycolysis pyruvate molecules can accept H+ to make lactate
- Also NAD+ can form NADH to take away some of these H+ ions
Describe the effect of temperature on the O2-Hb dissociation curve
- increase in temperature causes a right shift in the curve (weakens the bond between
O2 and Hb, favors unloading of O2 to muscle)
- occurs during exercise
- decrease in temperature causes a left shift in the curve (hinders O2 release to muscle)
Describe the role of 2-3 DPG on the O2-Hb dissociation curve
2-3 DPG affects the position of the oxygen dissociation curve. If there is a decrease in
2-3 DPG within the red blood cells, the oxygen dissociation curve favours the left. If
there is an increase in 2-3 DPG within the red blood cells the oxygen dissociation curve
,favours the right. Red blood cells are special in that they do not have a nucleus or
mitochondria, meaning they must rely on anaerobic glycolysis to meet the cells' energy
needs. A by-product of RBC glycolysis is the compound 2-3 DPG. This combined with
hemoglobin will reduce Hb's affinity for oxygen, thus causing a right shift on the oxygen
dissociation curve.
RBC concentrations of 2-3 DPG increase during exposure to altitude and anemia. This
means that the right shift in the oxyhemoglobin curve that occurs during heavy exercise
is not due to changes in 2-3 DPG, but to the degree of acidosis and blood temperature
elevation.
Describe the role of ventilation in regulating the acid-base balance of blood
In the case of decreased blood pH (increased free H+ ions in the blood), the CO2
carbonic anhydrase reaction shifts in favour of exhaling Co2. The body responds by
increasing the rate and depth of respiration to return to a pH of 7.35-7.45.
In the case of respiratory alkalosis (increase in pH due to decrease in H+), the CO2
carbonic anhydrase reaction will shift in the opposite direction towards H+ and CO2 in
order to maintain homeostasis. Ventilation will decrease.
Use the concept of the 02-Hb dissociation curve to explain fatigue (exercise capacity is
limited)
During high intensity exercise, changes in the O2-HB dissociation curve are evident and
can be used to explain the onset of fatigue. Beginning with the primary factor of pH, high
intensity exercise sees an increase in H+ ions within the blood, preventing oxygen
binding to hemoglobin and thus affecting muscular endurance. As well, lactate can form
by accepting these H+ ions. Temperature increases during exercise can also cause
fatigue, by weakening the bonds between O2 and hemoglobin. Ventilation and 2,3-dpg
can also affect it.
Increased pH and thus decreased H+ ions will impact the capacity of ventilation via
carbonic anhydrase. 2-3 DPG increases (byproduct of red blood glycolysis) and reduces
the affinity of Hb for oxygen (rightward shift, causing acidosis and blood temp elevation,
and thus changes from first submission).
, Lab 2
The term "maximal oxygen uptake" was coined and defined by Hill et al. and Herbst in
what decade? The answer contains only a four-digit number.
1920
Which of the following statements is false regarding the VO2max paradigm of Hill &
Lupton (1923)?
a) A high VO2max is a prerequisite for success in middle- and long-distance running.
b) VO2max is limited by ability of the cardiorespiratory system to transportterm-16 O2 to
the muscles.
c) There is not an upper limit to oxygen uptake.
d) There are interindividual differences in VO2max.
c) There is not an upper limit to oxygen uptake.
Not all subjects show a plateau in VO2 at the end of a graded exercise test (GXT), when
graphed against work intensity. It has repeatedly been shown that about what % of
subjects do not demonstrate a plateau when stressed to maximal effort? The answer
contains only a two-digit number.
50
Because not all participants achieve a plateau in VO2max with increasing workloads, it
is recommended that secondary criteria be applied to verify maximal effort. These
