Ace Essentials Of Exercise Science: Chapter 5 Physiology Of Training

Front 1

How much does the body's total energy expenditure increase during high-intensity exercise?

Back 1

15 - 25 time above expenditure at rest

Front 2

What are the two major adjustment in blood flow that must occur to meet increased demands of muscle during exercise?

Back 2

1. An increase in cardiac output

2. A redistribution of blood from inactive organs to the active skeletal muscle

Front 3

Cardiac Output

Back 3

HR X SV (Heart rate x Stroke Volume)

Front 4

Regulation of heart rate is controlled intrinsically by....

Back 4

SA node (Sinoatrial node), located in the posterior wall of the right atrium

Front 5

Regulation of heart rate is controlled extrinsically by...

Back 5

nervous and hormonal systems

Front 6

What is the AV (atrioventricular) node?

Back 6

A small knot of tissue located in the floor of the right atrium gives off many branches that facilitate ventricular contraction.

Front 7

Describe the vagus nerves' contribution to heart rate

Back 7

Vagus nerves are parasympathetic fibers that make contact with both the SA and AV nodes. Upon simulation they release acetylcholine which causes a decrease in the activity of both the SA and AV nodes, reducing heart rate.

Front 8

Chronotropic response

Back 8

Heart beats faster

Front 9

Inotropic response

Back 9

Increased force of heart contractility

Front 10

Cardiac Accelerator nerves

Back 10

Sympathetic fibers that innervate the SA node and ventricles

Front 11

Catcecholamines

Back 11

Epinephrine and Norepinephrine

Front 12

Frank-Starling mechanism

Back 12

The mechanism by which an increased amount of blood in the ventricle places a stretch on the cardiac muscle fibers, thereby causing a stronger ventricular contraction to increase the amount of blood ejected.

Front 13

Autoregulation

Back 13

Local control of blood distribution (through vasodilation) in response to a tissue's changing metabolic needs.

Front 14

Cardiac Output

Back 14

The amount of blood pumped by the heart per minute; usually expressed in liters of blood per minute.

Front 15

Systolic Blood Pressure (SBP)

Back 15

The pressure exerted by the blood on the vessel walls during ventricular contraction

Front 16

Diastolic Blood Pressure (DBP)

Back 16

The pressure in the arteries during the relaxation phase (diastole) of the cardiac cycle; indicative of total peripheral resistance.

Front 17

Diastole

Back 17

The period of filling of the heart between contractions; resting phase of the heart.

Front 18

Why is SBP affected more than DBP during exercise? (3 responses)

Back 18

1. Increased heart contractility and stroke volume increase the force with which blood leaves the heart.

2. Muscle action requires greater force or pressure to deliver blood into the exercising muscles.

3. Vasodilation within the exercising muscles allows more blood to drain from the arteries through the arterioles and into the muscle capillaries, thus minimizing changes in diastolic pressure.

Front 19

What percentage of total cardiac output is directed toward skeletal muscle at rest? during maximal exercise?

Back 19

Rest: 15 - 20%

Maximal Exercise: 80 - 85%

Front 20

What contributes to decrease in blood volume during early stages of exercise? (3 answers)

Back 20

1. Increased hydrostatic pressure from muscle contraction (squeezes fluid out of bloodstream)

2. Increase in osmotic pressure in the interstitial fluid space around muscles cells (due to accumulation of metabolites)

3. Loss of sweat

Front 21

What changes take place to conserve blood volume? (3 answers)

Back 21

1. Progressive increase in heart rate to maintain cardiac output and offset reduced SV

2. Vasoconstriction in non-exercising regions to increase blood pressure

3. Release of vasopressin (antidiuretic) and aldosterone... reduce water and sodium loss

Front 22

"The pump" weighlifters feel

Back 22

Transient hypertrophy - edema in the interstitial and intracellular spaces of the muscle resulting in a feeling of fullness in the muscle.

Front 23

What contributes to venous return during maximal exercise?

Back 23

Muscle pump: contraction of muscles compress veins forcing blood in them toward the heart.

Front 24

Minute ventilation (V(dot)E)

Back 24

A measure of the amount of air that passes through the lungs in one minute; calculated as the tidal volume multipled by the ventilatory rate.

Front 25

Part of the brain that controls respiration

Back 25

Medulla oblongata

Front 26

Humoral receptors role in ventilation

Back 26

Changes in chemicals in the blood trigger changes in ventilation. (Eg: carbon dioxide, hydrogen and potassium increases in blood trigger increase in ventilation, as does a decrease of oxygen in the blood)

Front 27

Neural influences in ventilation

Back 27

Feedback from peripheral receptors such as muscles spindles, Golgi Tendon Organs (GTOs), or joint pressure receptors can trigger a ventilation response. Also, mechanoreceptors in the right ventricle of the heart may also send signals to the respiratory control center.

Front 28

Ventilatory threshold (VT)

Back 28

Point of transition between predominately aerobic energy production to anaerobic energy production; involves recruitment of fast-twitch muscle fibers and identified via gas exchange during exercise testing.

Front 29

What is the average breathing rate at rest? during strenuous exercise?

Back 29

Rest: 12 - 15 breaths per minute

Exercise: 35 - 45 breaths per minute

Front 30

What is typical tidal volume at rest? during strenuous exercise?

Back 30

Rest: 0.4 - 1.0L

Exercise: up to 3.0L or greater

Front 31

VT1: First ventilatory threshold occurs when?

Back 31

Approximately the first time that lactate begins to accumulate in the blood. Caused by the need to blow off the extra carbon dioxide.

Front 32

VT2: Second ventilatory threshold occurs when?

Back 32

Occurs at the point where lactate is rapidly increasing with intensity. Probably represents the point at which blowing off carbon dioxide is no longer adequate to buffer the increase in acid that is occurring with increased exercise intensity.

Front 33

Primary hormone released by the adrenal medulla

Back 33

Epinephrine

Front 34

Responses to epinephrine (and norepinephrine)

Back 34

1. strength of cardiac contraction increases

2. vasoconstriction in non-exercising muscles

3. vasodilation of heart and active skeletal muscles

4. (NOT nor-e) dilation of respiratory passages, reduces digestive activity, reduces bladder emptying

5. affects CNS by promoting state of arousal

6. affects blood glucose concentration

Front 35

gluconeogenesis

Back 35

production of glucose from non-sugar substances

Front 36

glycogenolysis

Back 36

release of glycogen from liver and skeletal muscles

Front 37

lipolysis

Back 37

breakdown of triglycerides in adipose tissue to free fatty acids (FFA) for use as fuel

Front 38

How much can glucose uptake by skeletal muscles increase during exercise?

Back 38

7 - 20 times that during rest

Front 39

glucagon

Back 39

hormone released from the pancreas that stimulates and almost instantaneous release of glucose from the liver - low blood glucose levels stimulate its release

Front 40

cortisol

Back 40

steroid released from the adrenal cortex; plays many roles; stimulates FFA mobilization from adipose tissue, mobilizes gluconeogenesis in liver, decreases rate of glucose utilization by cells; slow acting; may play a role in tissue recovery and repair; prolonged elevations linked with many negatives, including abdominal obesity.

Front 41

growth hormone

Back 41

released from anterior pituitary gland; plays a major role in protein synthesis; support role of cortisol

Front 42

only macronutrient whose stored energy generates ATP anaerobically

Back 42

carbohydrates

Front 43

Epinephrine levels generally increase at exercise intensities above what VO2 max level?

Back 43

60%

Front 44

During exercise, glucose stored in non-exercising muscles can be delivered indirectly to the exercising muscles by what?

Back 44

glucose-alanine pathway: glucose is partially metabolized to pyruvate, to which an amino group is added to manufacture alanine (amino acid). Alanine travels to the liver where the amino group is removedand the pyruvates are reconstitued back to glucose, which are then released into circulation to the exercising muscle

Front 45

Cori cycle

Back 45

the cycle of lactate to glucose between the muscle and the liver

Front 46

Which type of muscle fiber produces more force?

Back 46

Fast-twitch muscle fibers product 10 - 20% more force than slow twitch (due to more myosin cross-bridges per cross-sectional area)

Front 47

Which type of muscle fiber has a faster shortening speed?

Back 47

Fast-twitch; contain more myosin ATPase (enzyme required for the breakdown of ATP)

Front 48

Which type of muscle fiber has higher efficiency (requires less energy to perform a given amount of work)?

Back 48

Slow-twitch: due to higher concentration of myoglobin, larger number of capillaries, and higher mitochondrial enzymes

Front 49

Decline in muscular performance associated with a reduction in the body's glycogen reserves

Back 49

muscle fatigue

Front 50

How much can metabolism rise during intense aerobic exercise by elite athletes?

Back 50

20 - 25 times above resting levels

Front 51

What is the body temperature above which protein structure of enzymes may be destroyed, resulting in cellular death?

Back 51

113F

Front 52

What is the body temperature at which the metabolism is slowed and cardiac function may be abnormal?

Back 52

93.2F

Front 53

What is the body's primary means of losing heat during exercise?

Back 53

Evaporation

Front 54

What are the four mechanisms the body uses to give off heat?

Back 54

1. radiation

2. convection

3. conduction

4. evaporation

Front 55

Chronic Adaptions to Exercise: Blood Volume

Back 55

Increases: plasma volume primarily. RBC can increase, but ratio of RBC to plasma still reduced

Front 56

Chronic Adaptions to Exercise: Blood Viscocity

Back 56

Reduced due to increased plasma, and higher plasma to RBC ratio. This enhances oxygen delivery to active skeletal muscles because blood flows more easily

Front 57

Chronic Adaptions: Heart Size

Back 57

Increased - increased left ventricular cavity (to hold increase blood volume), and increase thickness of left ventricular walls

Front 58

arterial-mixed venous oxygen difference

Back 58

the difference in oxygen content between arterial and mixed venous blood, which reflects the amount of oxygen removed by the whole body

Front 59

Fick equation

Back 59

The rate at which oxygen is consumed = cardiac output x arterial-mixed venous oxygen difference

Front 60

Chronic Adaptions: Heart Rate

Back 60

Resting and submaximal heart rate decrease - thought to be result of increase parasympathetic activity

Front 61

Chronic Adaptions: oxygen extraction (arterial-mixed venous oxygen difference)

Back 61

Increased

Front 62

Chronic Adaptions: Blood Flow to Active Muscles

Back 62

Enhanced: 1. increase capillarization of trained muscles 2. greater recruitment of existing capillaries 3. more effective blood flow distribution from inactive areas 4. increased blood volume

Front 63

Chronic Adaptions: Blood Pressure

Back 63

Both systolic and diastolic blood pressures tend to be lowered in borderline or moderately hypertensive individuals who exercise regularly

Front 64

Chronic Adaptions: Mitochondria

Back 64

Increase in quantity and size - improve the muscles ability to produce ATP, then thus the ability to use oxygen

Front 65

Chronic Adaptions: Oxidative Enzymes

Back 65

Activity increased; as a consequence there is a slower rate of muscle glycogen utilization and an enhanced reliance on fat as fuel at any given exercise intensity. (May results in ability to maintain a higher intensity throughout duration of workout.)

Front 66

Motor unit recruitment and synchronizations change with regular resistance training

Back 66

Motor units may act more synchronously (recruited together) enhancing contraction and increasing muscles ability to create force. Increased strength without muscle hypertrophy.

Front 67

Rate coding (muscles)

Back 67

The process by which the force production of a given motor unit varies from that of a twitch (single electrical stimulation) to that of tetnus (peak force product of the motor unit produced by summation of multiple twitches), by increasing the frequency of stimulation of the motor unit.

Front 68

Rate coding change with resistance training

Back 68

Rate coding may increase, which would result in an increase in the frequency of discharge of the motor units to allow a faster time to peak force production for the trained muscle.

Front 69

General hormonal changes with regular endurance training

Back 69

Hormonal response declines with regular training; increased efficiency due to improved sensitivity and/or responsiveness to hormone.