Ex Phsy: Chapters 4,5,6,7,8
Terms in this set (85)
-Fraction inspired oxygen
Percent of oxygen your breathing.
-On everest it hard because the pressure creates less
- .21 or 20%
-Sometimes called the Carrico index, is a comparison between the oxygen level in the blood and the oxygen concentration that is breathed.
fraction of expired air that is oxygen. The air we breathe in is 20.93% oxygen and we typically extract 3-6% of the air that is oxygen. Thus, the air that we exhale is usually 15-18% O2. Low values for FEO2 suggest that the subject is extracting O2 well and thus suggests that gas exchange in the alveoli is good.
fraction of inspired carbon dioxide.
fraction of expired air that is oxygen. The air that we breathe in has very little carbon dioxide (0.03%). As stated previously CO2 is produced as a result of cellular metabolism and thus most of the CO2 exhaled comes from metabolic processes. Typically the air that we exhale is 2.5-6% CO2.
RER and the influence it has on metabolic rate as well as the influence of substrate on RER
-Respiratory exchange ratio
- RER = VCO2/VO2
- The ratio between CO2 release and oxygen consumption (VO2).
- The amount of oxygen needed to completely oxidize a molecule of carbohydrate or fat is proportional to the amount of carbon in that fuel.
- At rest and during low intensity exercise the RER reflects the type(s) of fuel substrates being used by the cells for the production of ATP.
Compare direct and indirect calorimetry. What is the theory behind each measurement? How is each measurement made? What are the pros and cons for each method?
- 40% of the energy liberated during the metabolism of glucose and fats use used to produce ATP. The remaining 60% is converted to heat.
- To gauge the rate and quantity of energy production is to measure the body's heat production.
- Expensive to construct and to operate and are slow to generate results, so very few are in actual operation.
- Useful for measuring resting metabolism and energy expenditure over time.
- The rate of O2 and CO2 exchanged in the lungs normally equals the rate of their usage and release by the body tissues.
- Energy expenditure can be determined by measuring the respiratory exchange of O2 and CO2 .
- Estimates the total body energy expenditure.
- Must be completely oxidative for oxygen consumption to reflect energy metabolism accurately.
- Limited to steady-state aerobic actives lasting few minute or longer, which fortunately takes into account most daily activities including exercise.
- Simplest and oldest method.
- Douglas bag to collect expired air.
V̇O2 and V̇CO2 response to submaximal and maximal exercise
This is the ratio of carbon dioxide production to oxygen consumption (VCO2/VO2).
Quantitative tests and indices of anaerobic capacity
Relationship between endurance performance and aerobic capacity and other factors that impact performance
Economy of effort
Implies a balanced employment of forces, and a judicious expenditure of all resources with the object of achieving an effective concentration at the decisive time and place
The difference between the oxygen required for a given exercise intensity (steady state) and the actual oxygen consumption.
Absolute vs relative VO2 values
Relative to body mass. Absolute is the actual measurement, relative is in retrospect to bodymass
Substrate utilization during exercise of varying intensities
Anything really intense is carbohydrates
Low loads, longer you go, more fat you have to go.
Less glycogen and less glucose,
Causes of fatigue in general and during particular types of exercise
02 demand is more than 02 consumed which leads to an o2 deficit.
Inadequate energy deliver/metabolism
Accumulation of metabolic by-products
Failure of muscle contractile mechanism
Altered neural control of muscle contraction
DOMS, its causes and effects
- Usually peaks a day or two after the exercise bout. Eccentric muscle action seems to be primary initiator of this type of soreness.
- Structural damage to muscle cells and inflammatory reactions within the muscles.
Outline the sequence of events that is thought to contribute to the development of DOMS.
1. High tension in the contractile-elastic system of muscle results in STRUCTURAL DAMAGE to the membrane and its cell membrane.
2. The cell membrane damage DISTURBED CALCIUM HOMEOSTASIS in the injured fiber, inhibiting cellular respiration. This activates enzymes that degrade Z-lines.
3. Within a few hours there is a significant elevation in circulating neutrophils that participate in the INFLAMMATORY RESPONSE.
4. The products of INCREASED MICROPHAGE ACTIVITY and intracellular contents accumulate outside the cells. This stimulates the free nerve endings in the muscle.
5. Fluid and electrolytes shift into the area, creating EDEMA, which causes tissue swelling and activates pain receptors.
What exercise practices promote the development of DOMS, and what exercise practices help avoid the development of DOMS?
- start training at a very low intensity and progress slowly through the first few weeks.
- start training with a high intensity, exhaustive training bout.
Fatigue EAMCs its causes and effects and risk factors
1. Neuromuscular control becomes altered (excitation of muscle spindle and inhibition of the golgi tendon organ occur in fatigued muscles resulting in abnormal A-motor neuron activity and reduced inhibitory feedback (overwork the muscle)
2. Heat cramps= electrolyte defects (locking up) in the muscle to compensate for the large electrolyte sweat and plasma volume losses, fluids shift compartment. Action Potentials in muscle
Four major causes contribute to the development of fatigue, most likely in a synergistic manner. Discuss these four major causes and how each one may contribute to the development of fatigue.
1. A decreased rate of energy delivery (anaerobic glycolysis, and oxidative membrane.
2. Accumulation of metabolic by-products, such as lactate and H+.
3. Failure of the muscle fibers contractile mechanism.
4. Alterations in neural control of muscle contraction.
- The 1st 3 causes occur within the muscle itself and are often referred to as peripheral fatigue.
Physiology of resting and exercise heart rate, including the impact of training.
- averages 60 to 80 beats per minute in most individuals.
- Increases directly in proportion to the increase in exercise intensity, until near-maximal exercise is achieved. As exercise intensity increases it begins to plateau even as the exercise workload continues to increase.
Comparison of cardiac vs. skeletal muscle
- Heart and the adjacent proportions of large blood vessels.
- Branching shorter fibers are connected end to end by dark-straining regions called intercalated discs.
- Fibers are striated.
- Cells have single, central nucleus
- Continuous, rhythmic contraction through calcium-induced calcium releases.
- Contains only one fiber type.
- Contraction is involuntary.
- Throughout the body attached to the skeleton and fascia allow movement.
- Fibers are long, cylindrical, and unbranched.
- Muscle is striated.
- Cells have multiple nuclei.
- Contracts as needed to produce movement or resist gravity through excitation-contraction coupling.
- Contains several fiber types.
- Contraction is stimulated through voluntary or reflex action of the nervous system.
General heart anatomy and physiology, chambers, valves, flow of blood, opening / closing of values, heart sounds, systole and diastole events.
4. pulmonary valve
8. left atrium
9. bicuspid valve
10. left ventricle
Factors that influence blood flow.
Blood flows to where its needed the most
When metabolism increases so does blood flow
Impact of the autonomic nervous system neurotransmitters and hormones on the sino atrial node, heart muscle and vascular system.
sympathetic, - norephedrine
Sino atrial node can cause its own action potential. Ach causes the heartrate to decrease, causes heart muscle to decrease contraction, norephedrine is going to make it increase. More forceful contraction
Rest of heart muscle.
Regulation of blood flow and blood pressure by intrinsic and extrinsic mechanisms, including reflex control via baro receptors; including impact of exercise as well as heat on blood redistribution.
Blood function and components
2. Temperature regulation
3. Acid-base balance
Hematocrit as a measure of the % of blood volume consisting of RBCs and the impact it has on viscosity; as well as the impact of variations in plasma volume on hematocrit
- Varies among individuals, but a normal range is 41% to 50% in adult men and 36% ti 44% in women.
- The percentage of the total blood volume composed of cells or formed elements.
- The combination of low _____ with a high plasma volume, which decreases blood's viscosity, appears to have certain benefits for the bloods transport function because the blood can flow more easily.
- Low ____ frequently results from a reduced red blood cell count, as in diseases such as anemia.
Outline the electrical conduction system of the heart, starting with where a heartbeat originates and ending where the final contraction of a heartbeat occurs.
ECG tracing. What physiological events do the different electrical landmarks represent?
atrial depolarization and occurs when the electrical impulse travels from the SA node through the atria to AV node.
ventricular depolarization and occurs as the impulse spread from the AV bundle to perkinge finger and through ventricle
Discuss the relationships between blood pressure, blood flow, and vascular resistance. In practice, how does the body most often regulate flow?
-Blood flow= pressure difference/ resistance
-Higher resistance =slower blood flow
Explain the various intrinsic and extrinsic mechanisms the body uses to regulate blood flow and vascular resistance.
- The ability of the local tissues to dilate or constrict the arterioles that serve them and alter regional blood flow depending on the immediate needs of those tissues.
- Explains that redistribution of blood within an organ or tissue.
1. Metabolic regulation
- strongest stimulus for the release of local chemicals.
- Local arteries dilate to allow more blood to allow more blood to perfuse the area, delivering more oxygen.
2. Endothelium-mediated vasodilation
- Include nitric oxide (NO), prostaglandins, and the endothelium-derived hyperpolarizing factor.
- Important regulators to blood flow at rest and during exercise in humans.
3. Myogenic response
- Pressure changes within the vessels themselves can also cause vasolidation and vasoconstriction.
- the smooth muscle contracts in response to an increase in pressure across the vessel wall.
- Redistribution at the system or organ level is controlled by neural mechanisms.
- Comes from outside the specific area.
- When the sympathetic stimulation increases, further constriction of the blood vessels in a specific area decreases blood flow into that area and allows more blood to be distributed elsewhere.
- If sympathetic stimulation decreases below the level needed to maintain tone, constriction of vessels passively dilate, increasing blood flow into that area.
- Blood flow can be passively increased through a lowering of the normal tonic level of sympathetic outflow.
Explain the relationships between plasma volume, hematocrit, oxygen-carrying capacity, viscosity, and vascular resistance in the context of endurance training.
-Plasma is 55% blood, volume
-Hematocrit s total percent of volume composed of formed elements.
-Hematocrit is formed elements (red and while blood cells) over total blood volume.
-Hemoglobin is what allows O2 to be carried
-Twice as viscous as water
-Increase plasma volume and hemoglobin same percentage the democrat would stay the same
1. Tidal volume: The amount of air entering and leaving the lungs with each breath.
2. Vital capacity (VC): The greatest amount of air that can be expired after a maximal inspiration.
3. Residual volume (RV): The amount of air remaining in the lungs after maximal expiration.
4. Total lung capacity: The sum of VC and RV
PO2 and PCO2 in the alveoli, resting arterial blood and resting venous blood and muscle mitochondria.
-Partial pressure in O2 (159.1mmHg) and CO2 (0.2mmHg)
-Alveoli- create pressure gradient across the respiratory membrane.
-Resting arterial blood- matches blood flow to systemic circulation
Factors that influence oxygen diffusion capacity and how oxygen capacity changes with exercise.
-Exercise the oxygen difusion capacity my raise 3 times the resting heart rate because blood is returning to the lungs
Factors that influence O2-carrying capacity and what a normal carrying capacity would be
-at rest 21ml or oxygen per minute
Oxyhemoglobin dissociation curve - understand it under normal conditions and be able to explain the impact of shifts in the curve due to changes in temperature and pH that are typical during exercise at both the lungs and exercising.
-Shows the amount of hemoglobin saturated with oxygen at different PO2 values
-Flat upper portion means that at high PO2 concentrations such has the lungs, large drops of PO2 result in only small changes in hemoglobin saturation.
-blood becomes more acidic the curve shifts to the right
-pH- At tissue ph is lower causing oxygen to dissociate from hemoglobin. (give oxygen to tissue)
-Temp- hemoglobin unloads more oxygen when blood circulates through the metabolically heated active muscle.
Compare the the oxyhemoglobin dissociation curve and the O2-myoglobin dissociation curve.
-Myoglobin only releases it oxygen under conditions when the PO2 is very low.
Compare the arterial venous O2 difference with the arterial-mixed venous O2 difference.
- The difference in oxygen content between arterial and venous blood.
- mixed venous: the oxygen content of blood in the right atrium, which comes from all parts of the body, both active and inactive.
- Difference reflects the 4 to 5 ml of oxygen per 100 ml of blood taken up by tissues. The amount of oxygen is proportional to its use for oxidative energy production.
Can increase to 17 to 18 ml per 100 ml of blood during intense exercise.
Can increase to 15 to 16 ml per 100 ml of blood during maximal levels of endurance exercise.
Compare arterial venous O2 difference between exercising and non exercising muscle.
- Rest= 4-5 ml O2 per 100ml blood
-Exercise= 15 ml O2 per 100ml blood
Breathing control (inspiration and expiration) at rest vs. exercise
- An active process involving the diaphragm and the external intercostal muscles.
- The ribs and sternum are moved by external intercostal muscles.
- The pressure changes required for adequate ventilation at rest are really quite small.
- During maximal respiratory effort, like exercise, it is further assisted by the action of the other muscles in the neck and the pectorals in the chest.
- Is a passive process involving relaxation of the inspiratory muscles and elastic recoil of the lung tissue.
- As the diaphragm relaxes, it returns to its normal upward, arched position. As the external intercostal muscles relax, the ribs and sternum move back into the resting positions.
Role and response of chemoreceptors to regulate breathing rate and depth.
Send information about the chemical environment in the muscle and length and tension of the muscle
Fick's law for diffusion of a gas
- States that the rate of diffusion through a tissue such as the respiratory membrane is proportional to the surface area and the different in the partial pressure of gas between the two sides of the tissue.
Ex: The greater the pressure gradient for oxygen is across the respiratory membrane, the more rapidly oxygen diffuses across it.
Compare how oxygen and carbon dioxide are transported in the blood.
- Transported by the blood either:
1. Combined with hemoglobin in the red blood cells. (greater than 98%)
2. Dissolved in the blood plasma (less than 2%)
- Also relies on blood transportation.
1. As bicarbonate ions resulting from the dissociation of carbonic acid.
2. Dissolved in plasma.
3. Bound to hemoglobin.
Explain why the concepts of partial pressures and partial pressure gradients are so critical to understanding how the entire respiratory system functions.
-Mixture with gas
-If the pressure of gases were in equilibrium they would not move.
The primary means by which hormones maintain homeostasis is
Which of the following pairs of hormones typically act in opposition?
Which group of hormones exerts metabolic and cardiovascular effects during exercise?
Catecholamines - i.e. epinephrine and norepinephrine (same as adrenaline and noradrenaline)
Norepinephrine concentrations increase at ______ exercise intensities, and epinephrine concentrations increase at _______ exercise intensities.
Moderate & high
During exercise, glucagon concentrations ______, and insulin concentrations ______.
increase & decrease
Why do plasma glucose concentrations start to decline after prolonged endurance exercise?
Glycogen stores are depleted.
Which does NOT help increase plasma glucose concentrations during exercise?
ADH does not help increase plasma glucose concentrations during exercise
During exercise, growth hormone _______ the release of free fatty acids and ______ the uptake of cellular glucose.
Increases & decreases
Which of these is a consequence of low plasma volume?
heart strain increases
Aldosterone release leads to
Na+ retention followed by water retention
Renin is released when
kidneys sense low blood volume and pressure
Erythropoietin release is the primary stimulus for
red blood cell production
HRmax - what is it, how it is estimated?
- Estimated based on age because it shows a slight but predictable decrease of about one beat per year beginning at the age at 10 to 15 years old.
- Subtract age from 220 (220-age)
The mechanism by which an increased amount of blood in the ventricle causes a stronger ventricular contraction to increase the amount of blood ejected.
Differences between trained and untrained endurance athletes in: resting heart rates, maximal heart rates, resting stroke volume, maximal stroke volume, submaximal heart rate at the same workload.
Trained endurance athlete will have a lower resting heart rate slower than the untrained athlete. Maximal will be the same.
Resting stroke volume is the quantity of blood ejected at rest a trained athlete would have a higher resting stroke volume then an untrained athlete.
Factors that impact stroke volume such as preload, contractility, afterload
1. The volume of venous blood returned to the heart.
2. The capacity to enlarge the ventricle, to allow maximal filling.
3. The inherent capacity of the ventricle to contrast forcefully.
4. Aortic or pulmonary artery pressure.
Impact of catecholamine's on heart rate, stroke volume and cardiac output.
- Function as neurotransmitters in the sympathetic nervous system
1. Increased heart rate and force of contraction.
2. Increased metabolic rate
3. Increased glycogenolysis in the liver and muscle
4. Increased release of glucose and FFA's into the blood
5. Redistribution of blood to the skeletal muscles
6. Increased blood pressure
7. Increased respiration
Response of heart rate, blood pressure, stroke volume and cardiac output during steady state and incremental exercise to maximal exertion.
The mathematical product of heart rate x systolic blood pressure. Also called the double product.
Response of vascular beds during exercise in the heat
Which type of blood vessel is primarily responsible for redirecting blood flow?
What is the impact of an accumulation of metabolic by-products in muscle (H+, CO2, heat) on arterioles?
Increased blood pressure during exercise has what effect on plasma volume?
As blood pressure increases with exercise, the hydrostatic pressure within the capillaries increase. This increase in blood pressure forces water from the intravascular compartment to the interstitial compartment. Also, as metabolic waste products build up in the active muscle, intramuscular osmotic pressure increases, which draws fluid out of the capillaries to the muscle.
If dehydration causes hematocrit to rise to 60%, what is the consequence?
An increase in red blood cell count is not accompanied by a similar increase in plasma volume, blood viscosity and vascular resistance will increase, which could result in reduced blood flow.
Impact of the Valsalva maneuver on preload, cardiac output, arterial blood pressure
Causes an enormous increase in intrathoracic pressure. Much of the subsequent blood pressure increase results from the body's effort to overcome the high internal pressures created.
Ventilatory regulation during exercise
When you start to exercise you start to ventilate more independently from feedback from kemo receptors.
Impact of hyperventilation PCO2, pH and the drive to breath
PCO2= Partial pressure of carbon Dioxide
Hyperventilate= PCOs goes down, pH goes up, Drive to breath goes down.
Ventilatory equivalent for oxygen and carbon dioxide changes when anaerobic metabolism is increasing (anaerobic threshold)
The amount of meters of ventilation in order to consume a leader of oxygen. A ration of ventilation to oxygen consumption.
During maximal exercise, respiratory muscles can receive up to what percentage of cardiac output?
How are the respiratory muscles different than other skeletal muscles
-They move your chest wall
-They can both voluntary activated and or involuntary activated
What is the impact of strenuous exercise on urine produced (hint - has to do with the kidney's role in acid base balance)
You are going to get acidic urine with strenuous exercise
Discuss the changes that occur in heart rate, stroke volume, and cardiac output from rest to maximal exercise. Why do they occur, and how do they interact with each other to maintain adequate cardiovascular support for exercise?
-Cardiac output increase linearly, HR increases linearly, SV. increases linearly for about 40-60% of the max and then in plateaus
-Some evidence that elite trained athletes have a longer period of times in increasing strove volume (more that 60%)
-Changes occur because cardiac output is increasing because HR and SV are increasing. Increasing cardia output is to increase exercise.
-If Q goes up and PR goes down you can pass out.
Discuss the major factors that contribute to an increase in muscle blood flow during exercise.
-What drives blood flow?
-Demand for move oxygen
-Pressure gradient=p1 should be greater than p2 for blood to flow down.
-muscles decrease the pressure by dilating
Define and then describe the relationship between anaerobic threshold, lactate threshold and ventilatory threshold.
-Anaerobic threshold: when you start to accumulate hydrogen ions because glycosides is happening too fast for the mitochondria to process it.
-When glycolysis has to make ATP to help the aerobic process and in doing so it creates pyruvate that can't get through the mitochondria fast enough so they create lactic acid.
-Lactic acid gets formed and an increase in lactic acid means you reach the anaerobic threshold.
-before anaerobic threshold VCO2 is related to the metabolic process totally. (metabolically produced in the mitochondria)
Maximal oxygen consumption (VO2 max) is often described as the most important variable for an exercise physiologist to know. Based on what you have learned about this variable so far, discuss whether you agree with this statement and why.
What is normal resting heart rate?
72 or 71
What determines the normal resting heart rate?
Your central nervous system
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