Exercise Physiology Test 1

A.V. Hill

heat production during muscle contraction and recovery.

Otto Meyerhof

relationship oxygen (O2) consumption and lactic acid in muscle

August Krogh

function of capillary circulation

D.B. Dill

conducted Harvard Fatigue Laboratory from 1927-1947.

Independent Variable

manipulated by researcher (x-axis)
ex: intensity, duration, frequency

Dependent Variable

changes in response to independent variable, can NOT control (y-axis)
ex: blood pressure, heart rate, fatigue

Homeostasis

maintaining balance in normal or "internal" environment
ex: 37'C and pH 7.4

Steady State

balance between demands placed on the body and the bodies response to those demands. This is disrupted when you reach your max or body demands change

What are two control systems are employed by the body to maintain or restore homeostasis?

Intracellular
Organ

What is the purpose of a biological control or feedback system?

mechanisms that respond to stress to keep homeostasis

Negative Feedback

reverse initial stimulus to bring back to norm

Positive Feedback

enhances the stimulus

Sensor

detects stimulus and sends signal to control center (afferent)

Control Center

receives and asses info given and sends to effector (efferent)

Effector

makes a change via muscles and glands

Intracellular System

reside inside the cell; regulates activities such as protein breakdown, synthesis, and energy production

Organ System

helps maintain homeostasis; pulmonary and circulatory systems work together to replenish oxygen and remove carbon dioxide to keep homeostasis during exercise

Organic Compounds

contain carbon

Inorganic Compounds

do NOT contain carbon

Mitochondria

powerhouse of cell involved in oxidative conversions of food stuffs

Endergonic

needs energy to be added to reactants

Exergonic

reactions that give off energy

Coupled Reactions

reactions that are linked with liberation of free energy and being use to drive a second reaction; release of exergonic derives endergonic reaction

Oxidation

removing an electron; coupled reaction
molecule that donates an electron is reducing agent

Reduction

addition of electron; couples reaction
molecule that accepts an electron is oxidizing agent

NAD+

oxidized;
derived from B3

NADH

reduced
NAD+ +H+=NADH

Enzymes

catalyst protein (amino acids) play a role in speeding up or catalyzing chemical reactions
altered by temp and pH
ends in "ase"
lower energy of activation to speed up chemical reactions

Coenzymes

activate enzyme
water soluble B vitamin

What are Carbohydrates composed of and how many k/cals does it contain?

composed of carbon, hydrogen and oxygen
4 k/cal

Carbohydrates

stored as glucose in blood sugar (C6H12O6)

What are the 3 Forms of carbohydrates?

monosacceride, disacceride, and polysacceride;
these are sugars containing glucose and fructose

Glycogen

is a polysacceride (CHO) where cells breakdown glycogen to glucose in the liver and muscle which is called "glycogenolysis

What are fats composed of and how many k/cals does it contain?

composed of carbon and oxygen
9k/cal

What are the 4 types of fat?

fatty acids, triglycerides, phospholipids, and steroids

Fatty Acids

long chain stored as triglycerides
ex; saturated fat, unsaturated fat, monosaturated fat, and polysaturated fat

Triglycerides

fatty acids and 1 molecule of glycerol in skeletal muscle "lypolysis

Phospholipids

not used as energy source but structural of cell membrane insulating sheath around nerve fibers

Steroids

cholesterol, and synthesize sex hormones

What are proteins composed of and how many k/cals does it contain?

composed of carbon, hydrogen,oxygen, and nitrogen
4k/cals

Proteins

composed of amino acids that contributes as fuel in muscle;
can be converted in the liver into glucose and synthesize glycogen or converted into fuel in metabolic pathways

ATP

adenine triphosphate; energy carrying molecule
synthesis;ADP +Pi---- ATP
breakdown; ATP+ + H2O---ATPase---->ADP + Pi + Energy = muscular contraction

What is metabolism and describe the two types?

state of all chemistry in the body;
anabolic-build (chronic)
catabolic-breakdown (acute)

Glycogenolysis

breakdown of glycogen to glucose;
enzyme phosphorlase

Glycolysis

occurs in sacroplasm of muscle cell
breakdown of glucose or glycogen into two molecule of pyruvate and two molecules of lactate
net gain of 2 ATP

Proteolysis

breakdown of protein;
enzyme protase

Lipolysis

breakdown of triglycerides into lipolysis or fatty acids

Cell membrane

semi permiable; filters

Nucleus

contains protein synthesis

Cytoplasm

contains organelles, cytosol, and mitochondria

Gluconeogenesis

breakdown of fat and protein to make glucose

ATP-PCr System
(Phosphagen System)

does not involve O2 (anaerobic)
short term, high intensity exercise lasting fewer than 14 seconds
ex; 50 M, high jumping
muscle cells store small forms so it is LIMITED

What enzyme breaks down the ATP-PC System?

catalyzed by creatinekinase;
PCr + ADP--creatinekinase---ATP
high energy, 5 or 6 times greater concentration that ATP does
conducts muscle contraction in muscle cells
1.8 k/cal mol

What are the three immediate energy sytstems?

ATP;first cellular source of energy
PCr; 2nd cellular source of energy
myokinase enzyme; 3rd cellular source of energy

ATP hydrolysis

first cellular energy system;
ATP + H2O--ATPase--> ADP + Pi + Energy
8.4 k/cal mol

Myokinase

3rd cellular source of energy
has the ability to take two ADP and create one ATP
ADP + ADP --myokinase-- ATP +AMP
.9k/cal mol

Non Oxidative Energy System (Fast Glycolysis)

does not involve O2 (anaerobic)
from glucose and glycogen only CHO
from 10-14 sec

Oxidative (phosphorylation) Energy System

requires O2 (aerobic)
endurance activities
requires glucose and glycogen in slow glycolysis
fatty acids and amino acids

What are the two phases in the Non Oxidative (Fast Glycolysis) Energy System?

1)energy investment phase
2)generation phase

Energy Investment Phase

stored ATP is used to form sugar phosphate
contains glucose (6-Carbon mol) C6H12O6
requires 2ATP
formation of two 3-Carbon molecules

Energy Generation Phase

two 3-Carbon molecules formed
formation of two 3-Carbon pyruvate or two 3-Carbon lactate which releases energy

How many ATP and NADH are formed in the energy investment phase?

4 ATP produced
2 NADH molecules

What is the net gain of ATP in fast glycolysis?

2 ATP

What metabolic pathways are capable of making ATP without oxygen?

ATP-PCr System and Glycolysis

What happens when there is no oxygen present in glycolysis?

Pyruvate catabolizes lactate by the enzyme lactatedehydroganase (LDH) into lactic acid
NADH + H---LDH----NAD REDUCTION

Pyruvate

C3 catabolizes to Acetyl CoA (C2)
becomes C2; remaining carbon is given off as CO2
REDUCTION

Aerobic ATP Production

involves interaction of two metabolic pathways;
krebs cycle (citric acid cycle)
electron transport chain (ETC)

Krebs Cycle

complete oxidation (hydrogen removal) of CHO, fats, proteins, using NAD and FAD as hydrogen carriers

Acetyl-CoA

combines with oxaloacetate C4 to form citrate C6 whish then regenerates to oxaloacetate giving off n2 molecules of CO2

one molecule of glucose

0

How many molecules of NADH and FADH are formed in one turn of Kreb?

3 NADH
1 FADH

GTP

energy-rich compound derived from NADH and FADH; transfers phosphate group to ADP to ATP then taken to ETC.

Lactate dehydrogenase

this enzyme is activated when O2 is not available to accept H+ so pyruvate can accept the hydrogens in order to form lactate

CHO in Krebs

for every molecule of glucose entering glycolysis two molecules of pyruvate are formed causing 2 turns of Kreb giving off CO2

Fats in Kreb

are broken down to form fatty acids and use beta oxidation to form Acetyl-CoA to start kreb (lypolyisis give off electrons)

Proteins in Kreb

can be converted to glucose or pyruvate and some to Acetyl-Co A to start kreb (give off CO2 and NH3)

What are the four Rate Limiting Enzymes?

1) Creatine Kinase
2) Phosphofructosekinase
3) Isocitrate dehydroganase
4) Cytochrome oxidase

Creatine Kinase

ATP-Pc

Phosphofructosekinase

Glycolysis

Isocitrate dehydroganase

Krebs

Cytochrome oxidase

Electron Transport Chain

Yields 32 ATP (slow glycolysis)

aerobic metabolism of one molecule of GLUCOSE

Yields 33 ATP (fast glycolysis)

aerobic metabolism of one molecule of GLYCOGEN

Aerobic resperation

34% total energy

Energy released as heat-

66%

Is O2 present on the Kreb Cycle?

NOOO

Fate of Lactate 70%-

oxidized by other tissues (slow twitch)

Fate of Lactate 20%-

converted to glucose or glycogen in liver (cori CYcle)

Fate of Lactate 10% -

converted to amino acids

The higher acidity of the cell as a result of lactic acid production alters enzymatic activity

muscle fatigue

Absolute

L/min resting---- .25L/min resting

Relative

mL/kg/min------------- 3.5mL/kg/min resting

What is considered a low blood lactate level?

<1.0mmol/L

MET's

metabolic equivalents is the expression of energy costs for activites in a simple unit.
=3.5mL/kg/min (resting)

5 Criteria for VO2 Max

1- the plateau of oxygen consumption
2- the attainment of RER of 1-1.5 or higher
3- the attainment of age predicted heart rate
4- the exhaustion of the participant
5- blood lactate > 8.0 mM/L (resting <less than one)

Oxygen deficit

delay in O2 uptake at beginning of exercise

Does a trained/untrained individual have a higher or lower O2 deficit?

trained subjects have lower O2 deficit due to better developed aerobic capacity.

EPOC (Excess Post exercise Consumption

Post exercise, O2 concumption does not return to resting levels immediately; termed O2 debt
untrained individual have higher O2 debt because it takes longer to recover

Rapid Curve

steep decline in O2 consumption
replenish ATP, PC and oxygen stores

Slow Curve

slow decline in O2 consumption
elevated body temp
elevated epinephrine/epinephrine
elevated breathing and heart rate
conversion of lactic acid to glucose

EPOC ---Resythesize of PC in muscle

Fast Curve

EPOC---Restortion of muscles and blood oxygen stores

Fast Curve

EPOC---- Lactate Removal

Slow Curve

EPOC----Elevate body temp

Slow Curve

EPOC---- Elevated horomones

Slow Curve

EPOC---Postexercise elevation of HR and breathing

Slow Curve

What percentage of the lactate is oxidized by working muscle tissue?

80%

What percentage of lactate is reconverted into glycogen?

20%

Lactate Threshold

the point at which blood lactic acid arises systemically during incremental exercise
50-60% VO2 max in UNTRAINED
65-80% at higher work rates in TRAINED subjects

OBLA

Onset blood lactate levels reach 4mMol/L
resting 1m/mol

Metabolic CO2 Porduction

oxidative phosphorylation

non-metabolic CO2 production

bicarbonate buffering (HCO3-)
combines with hydrogen creating carbonic acid