Quiz 2

Exercise Science 05 with Mookerjee at Bloomsburg University of Pennsylvania

About this deck

By: RACHEL WIELLER
Textbook:

Exercise Physiology: Theory and Application to Fitness and Performance
Created: 2011-03-28
Size: 35 flashcards
Views: 21

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Dalton's Law of Partial Pressures

the total pressure of a gas mixture is equal to the sum of the pressure that each gas would exert independently.

PO₂

partial pressure of oxygen.

in air - 20.93%.

expressed as a fraction- 0.2093.

about 159 mmHg

(^ in altitude = lower P)

Benz Pressure

In Water (Scuba Diving):

When you are deep in water you can feel the pressure build up in your ears.

Fick's Law of Diffusion

The rate of gas transfer (V gas) is proportional to the tissue area, the diffusion coefficient of the gas, and the difference in the partial pressure of the gas on the two sides of the tissue and inversely proportional to tissue thickness.

Vgas = (A/T) * D (P1-P2)

v= volume

A= tissue area

T= tissue thickness

D= diffusion coefficient (Constant for each gas!!)

p1-p2= difference in partial pressures

Blood flow to the lung:

-pulmonary circuit

same rate of flow as systemic circuit
lower pressure.

Most of the air is expelled after only 1 second. (FEV1)

become familiar with this process

When standing most of the blood flow is to the base of the lung.

If you hang upside down the reverse will happen.

works towards maximum efficiency (V/Q relationships)

Q= BLOOD FLOW

V= alveolar volume.

Indicates matching of blood flow to ventilation
ideal = 1.0
base is over perfused...<1.0 (bottom) because more blood flow and less air flow
apex is under perfused >1.0 (top) because there is less blood flow

Normal Ratios (V/Q) for Apex and Base

Apex: Ventilation= 0.24 L/min ; Flow= 0.07 L/min ; Ratio= 3.3

Base: Ventilation= 0.82 L/min ; Flow= 1.29 L/min ; Ratio= 0.63

Oxygen Transport in Blood

Approximately 99% of oxygen transported in blood is bound to hemoglobin (Hb)

Oxyhemoglobin: Oxygen bound to Hb

Deoxyhemoglobin: Oxygen not bound to Hb

The amount of oxygen that can be transported per unit volume of blood is dependent on the concentration of Hb.

Anemia is severely impaired (Run 5k+)

Bc: RBC circulation in feet// running force= 72x weight.

RBC are killed/damaged (not true anemics) can be corrected for.

Foot-strike hemolysis (TRAUMA)

Sigmoid Curve (S-shaped)

^ PO2 the more Hb saturation.

Blood pH decreases during heavy exercise, results in a Rightward shift.

Bohr Effect
Favors "overloading" of O2 to tissues

During exercise binding of o2 to Hb is less!! this is beneficial because it unloads more oxygen more rapidly to tissues.
Can reduce fatigue (theoretically) and performance

Increased blood temperature = a weaker O2-Hb bond
Rightward Shift of Curve.
.2-.5*C is enough to shift curve.
Hypothermic would have a L shift.
temperature ^ when execising

Oxyhemoglobin Dissociation Curve (cellular level)

RBC must rely on anaerobic glycolysis to meet the cells energy demands.
a biproduct is 2-3DPG.
Can combine with hemoglobin and reduce Hb affinity for oxygen
2-3 increase with altitude.
acute immediate response to high altitude

Myoglobin shuttles o2 from cell membrane to mitochondria
Bonds more rapidly and at a higher rate then Hb
Higher affinity for o2
even at a low pressure (20 mmHG) there is almost 90% saturation
allows myoglobin (mb) to create o2 stores
muscles NEEDS o2 supply

dissolved in plasma (10%)
Bound to Hb (20%)
Bicarbonate (70%)

Co2 has a higher affinity with Hb then o2.

CO2 + H20 <---> H2CO3 <---> H+ + HCo3-

catalyzed by carbonic anhydrase.

Important in buffering H+

Co2 + Hb ---> Carbaminohemoglobin

Intracellular Buffers : (Accept H+ ions)

3 mechanisms of Co2 transport

Proteins

Contain weak acid groups which accept H ions (COO- and NH3)

2. Phosphate Groups (PO4-)

Weak acids capable of accepting H ions

3. Bicarbonate-Carbonic Acid

HCO3- buffers strong acids ---> weak acids
H2CO3- buffers strong bases ---> weak bases

How do Lungs act as a Buffer?

When we hyperventilate, we prevent acidosis.

Lactic Acid

Produced during exercise
Intracellular buffers are the first line of defense
extracellular buffers are primary means of balancing pH
Lungs play an important role (reduce LA by removing CO2)

How do Lungs and Kidneys Balance pH

by adjusting ratio of bicarbonate to CO2

4 Acid-Base Imbalances

Metabolic Acidosis
Respiratory acidosis (hyperventilate)
Metabolic Alkalosis (vomit)
Respiratory Alkalosis

METABOLIC ACIDOSIS

During ex.

HCO3- is lowered due to accumulation of acid.

HCO3/PCO2 falls lowering pH

H+ increase stimulates breathing which lowers pCO2

-respiratory compensation

initially, vent. increases rapidly

then a slower rise toward steady-state.

po2 and pco2 then maintained

During Prolonged submaximal ex.

Ve tends to drift upward
little change in PCO2
^ in Ve is not due to ^ PCO2

Incremental Exercise

Linear ^ in Ve

up to about 50-75% of VO2 max

exponential ^ beyond this point

Ventilatory threshold (Tvent)

Inflection pt is where Ve increases exponentially

Decrease in arterial P02 near exhaustion

pH maintained at a higher work rate

Tvent occurs at a higher work rate

Trained can handle lactate longer

Less Po2 in blood bc muscles are consuming o2.

Elite po2- can ^ C.O. by 5x (20-25 L/min) blood is traveling so fast through the capillaries so it doesnt have time to pick up O2

Exercise induced Hypoxemia stats:

1980s: 40-50% of elite male endurance athletes were capable of developing.

1990s: 25-51% of elite female endurance athletes were also capable

CAUSES of ex. induced hypoxemia

Ventilation- perfusion mismatch!

diffusion limitations due to reduced time of RBC in pulmonary capillaries due to ^ C.O.

respiratory control center:

receives neural and humoral input
feedback from muscles
co2 levels in the blood
regulates resp. rate

Input to the Respiratory Control Centers

HUMORAL CHEMORECEPTORS:

1) Central Chemoreceptors

-located in medulla

-pco2 and H+ conc in CSF

2) peripheral chemoreceptors

-aortic and carotid bodies

-Po2, pco2, H+ and k+ in the blood

3) neural inpul

-From motor cortex or skeletal muscle.

as ex. intensity ^

metabolic rate ^

and pCO2 ^

with better saturation you done have to ventilate as much

easiest way to work.

if you have more o2 why ventilate as much

ventilatory control during ex

submaximal ex

linear increase due to

-central commance

-humoral chemoreceptors

-neural feedback

Heavy ex

Exponential rise above Tvent

^ blood [H+]

Vent is lower at the same work rate following training

may be due to lower blood la leverls

results in less feedback to stimulate breaking.

Do Lungs Limit exercise Performance?

low to moderate intensity exercise:

- pulmonary system is not seen as a limitation

Maximal Exercise

- not thought to be a limitation in healthy ind. at sea level

- may be limiting in elite endurance athletes

- new evidence that respiratory muscle fatigue does not occur during ^ intensity ex.

About this deck

By: RACHEL WIELLER
Textbook:

Exercise Physiology: Theory and Application to Fitness and Performance
Created: 2011-03-28
Size: 35 flashcards
Views: 21

About StudyBlue

“Simply amazing. The flash cards are smooth, there are many different types of studying tools, and there is a great search engine. I praise you on the awesomeness.”
Dennis