New version page

FSU PET 3380C - Chapter 7 Book Notes

Documents in this Course
Test 1

Test 1

46 pages

Test #1

Test #1

18 pages

Notes

Notes

4 pages

Notes

Notes

9 pages

Notes

Notes

9 pages

Exam 2

Exam 2

8 pages

Test 1

Test 1

17 pages

EXAM 1

EXAM 1

6 pages

Exam 4

Exam 4

16 pages

Exam 2

Exam 2

14 pages

Exam 4

Exam 4

15 pages

Exam 1

Exam 1

11 pages

Exam 3

Exam 3

7 pages

Notes

Notes

14 pages

Exam 2

Exam 2

15 pages

Exam 4

Exam 4

16 pages

Exam 3

Exam 3

18 pages

Exam 2

Exam 2

15 pages

Load more
Upgrade to remove ads

This preview shows page 1 out of 4 pages.

Save
View Full Document
Premium Document
Do you want full access? Go Premium and unlock all 4 pages.
Access to all documents
Download any document
Ad free experience

Upgrade to remove ads
Unformatted text preview:

Chapter 7 Book Notes PET3380CImmediate Energy: The ATP-PCr System• short term, high intensity exercise comes almost exclusively from the intramuscular high energy phosphate sources, adenosine triphosphate and phosphocreatineShort Term Energy: The Lactic Acid System• the energy to phosphorylate ADP during such exercise comes mainly from stored muscle glycogen breakdown via anaerobic glycolysis and results in lactate formation• large, rapid accumulations of blood lactate occur during maximal exercise that lasts between 60 and 180 seconds• decreasing the intensity of such exercise to extend the exercise period correspondingly decreases the rate of lactate accumulation and the final blood lactate levelLactate Accumulation • blood lactate does not accumulate (it does still form) at all levels of exercise• the more intense the exercise, the more lactate accumulates◦ when glycolytic metabolism predominates, NADH production exceeds the cell's capacity for shuttling its hydrogens (electrons) down the respiratory chain because of insufficient oxygen supply at the tissue level• the imbalance in hydrogen release and subsequent oxidation (ie. the NAD+/NADH ratio) causes pyruvate to accept the excess hydrogens (two) ◦ the new pyruvate with two additional hydrogens forms lactate• for untrained people, lactate begins to rise at about 50 to 55% of their VO2 max• for trained individuals, lactate begins to accumulate at about 75% of their VO2 max◦ they have a higher blood lactate threshold◦ use glucose and fatty acid catabolism◦ maintain a lower level of lactate, which conserves glycogen reserves• under aerobic conditions, 70% lactate is oxidized by other tissues, 20% is converted to glucose in muscle and the liver and 10% is converted to amino acids◦ ie. there is no net gain of lactate• blood lactate only accumulates when its disappearance (oxidation, etc..) does not match its production (ie. your producing more than you can get rid of)• another factor for lactate accumulation is the muscle type◦ fast twitch fibers favor the conversion of pyruvate to lactate◦ slow twitch fibers favor the conversion of lactate to pyruvate, on the other hand• trained athletes perform at higher, steady rate intensities than untrained individuals◦ most likely related to three factors:▪ their specific genetic endowment (ie. percentage of specific fibers their born with)▪ specific local training adaptations that favor less lactate production▪ more rapid rate of lactate removal at any exercise intensity◦ also a side note; capillary density, size and number of mitochondria increases with training, as well as the concentration of enzymes and transfer agents in aerobic metabolismLactate Producing Capacity• producing high blood lactate levels during maximal exercise increases with specific sprint power anaerobic training and decreases when the training stops• sprinters often achieve 20 to 30% higher lactate levels than untrained individuals• there are three possible mechanisms:◦ improved motivation that accompanies exercise trainingChapter 7 Book Notes PET3380C◦ increased intramuscular glycogen stores that accompany training◦ training induced increase in glycolytic related enzymes▪ the 20% increase in glycolytic enzymes falls well below the two to threefold increases in aerobic enzymes with endurance trainingLong Term Energy: The Aerobic System• because glycolytic reactions produce relatively few ATP, aerobic metabolism provides nearly all of the energy transfer when intense exercise continues beyond several minutesOxygen Consumption During Exercise• pulmonary oxygen uptake - oxygen consumption by the lungs• steady state/rate - refers to the flat portion (plateau) of the oxygen consumption curve◦ oxygen consumption increases rapidly until it reaches this steady rate◦ this reflects the balance between energy required by the working muscles and ATP production in aerobic metabolism◦ no appreciable blood lactate accumulates under steady rate (aerobic) metabolic conditions▪ so theoretically a person could go forever if they wanted to (excluding environmental influences, fluid loss, electrolyte depletion, and etc...)• highly trained individuals can maintain a steady rate for long periods of time at higher intensities... this is because:◦ the high capacity of the central circulation to deliver oxygen to working muscles◦ the high capacity of the exercised muscles to use available oxygenOxygen Deficit• the oxygen consumption curve does not increase instantaneously to a steady state• though the energy requirement remains the same throughout the exercise, oxygen consumption remains below the steady level during the transitional stage...◦ this is because no matter how much oxygen is available to the body, it still begins with the process of anaerobic breakdown of ATP◦ hydrogen production and subsequent oxidation become proportional to the exercise energy requirement after several minutes of submaximal exercise• oxygen deficit - the difference between the total oxygen consumption during exercise and the total that would be consumed had steady rate oxygen consumption been achieved from the start◦ it represents the immediate anaerobic energy transfer from the hydrolysis of intramuscular high energy phosphates and glycolysis until steady rate energy transfer matches the energy demands• energy for exercise does not simply occur from activating a series of energy systems that “switch on” and “switch off,” but rather from smooth blending with considerable overlap of one mode of energy transfer to anotherOxygen Deficit in the Trained and Untrained• the endurance trained person reaches steady rate more rapidly with a smaller oxygen deficit than sprint power athletes, cardiac patients, and the untrained◦ more rapid increase in muscle bioenergetics◦ increase in overall blood flow (cardiac output)◦ disproportionately large regional blood flow to active muscle complemented by cellular adaptationsMaximal Oxygen Consumption• maximal oxygen consumption (VO2 max) - when oxygen consumption plateaus or increases only slightly with additional increases in exercise intensityChapter 7 Book Notes PET3380C◦ it provides a quantitative measure of a person's capacity for aerobic ATP resynthesisFast and Slow Twitch Muscle Fibers• fast twitch (FT) or type 11 - a type of muscle fiber that has two subdivisions◦ type 11a - rapid


View Full Document
Download Chapter 7 Book Notes
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view Chapter 7 Book Notes and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Chapter 7 Book Notes 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?