Exercise Physiology: Homeostasis and Feedback

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Questions and Answers

What is the primary location for aerobic ATP production?

Mitochondria (correct)

Cytoplasm

Sarcoplasm

Endoplasmic reticulum

Which substance serves as the universal stimulant for rate-limiting enzymes in ATP production?

NADH

ADP (correct)

ATP

What is the main fuel source during short duration, high-intensity exercise?

Glucose

Intramuscular triglycerides (correct)

Glycogen

Free fatty acids

What is the role of cytochrome c oxidase in aerobic ATP production?

It serves as the rate-limiting enzyme in the ETC Signup and view all the answers

What happens during EPOC concerning substrate use for ATP production?

Primarily free fatty acids are used Signup and view all the answers

Which factor is inversely related to stroke volume during exercise?

Mean arterial pressure (MAP) Signup and view all the answers

What characterizes the crossover concept during increased exercise intensity?

A shift from predominantly fat to carbohydrate usage occurs Signup and view all the answers

What is the most significant factor affecting heat loss during exercise in a hot environment?

Relative humidity Signup and view all the answers

What physiological adaptation occurs in the body within the first week of heat acclimation?

Increased catecholamines Signup and view all the answers

What is a primary mechanism for heat loss during exercise?

Evaporation Signup and view all the answers

Which factor is NOT an environmental consideration for cold injury?

Altitude Signup and view all the answers

Which of the following factors contributes to an increase in maximal stroke volume (SV max)?

Increase in contractility Signup and view all the answers

In terms of endurance training adaptations, what improves (a-v̅)O2 diff max?

Increased mitochondrial count Signup and view all the answers

What are the training principles associated with overload and specificity?

Intensity and volume Signup and view all the answers

How does gender affect individual susceptibility to cold injury?

Women are at a disadvantage in cold environments Signup and view all the answers

What is the relationship between force and velocity in muscle contraction?

Inverse; maximum shortening occurs at low force Signup and view all the answers

Which factors contribute to muscle fatigue?

Both central and peripheral fatigue, depending on intensity and duration Signup and view all the answers

How do oxidation and reduction reactions transfer energy?

By the transfer of electrons between compounds Signup and view all the answers

What is the primary end product of anaerobic ATP production via ATP-PC?

ADP and inorganic phosphate Signup and view all the answers

Which hydrogen carrier is reduced to form NADH?

NAD+ Signup and view all the answers

What is the replenishment time for ATP production using the ATP-PC pathway?

10-15 seconds Signup and view all the answers

In rapid glycolysis, how many ATP molecules are produced from one molecule of glucose?

2 ATP Signup and view all the answers

Which of the following best describes rate-limiting enzymes?

They control metabolic pathways and can be regulated by metabolic products Signup and view all the answers

What is the primary role of muscle spindles?

Respond to changes in length and maintain posture Signup and view all the answers

Which type of motor unit is characterized as the largest, fast, but also fatigable?

Type IIx Signup and view all the answers

What occurs during the inverse stretch reflex facilitated by Golgi tendon organs?

Relaxation to reduce tension via IPSPs Signup and view all the answers

What is the significance of the size principle in motor unit recruitment?

Smallest motor units are recruited first to match external demands Signup and view all the answers

What component of the muscle fiber acts as a storage site for calcium?

Sarcoplasmic reticulum Signup and view all the answers

What is the primary fuel source for shivering during cold exposure?

Fat Signup and view all the answers

Which step in muscle contraction involves the binding of calcium to tropomyosin?

Contraction-coupling Signup and view all the answers

What physiological change occurs during heat acclimatization regarding sweat?

Earlier onset of sweating Signup and view all the answers

What role do satellite cells play in muscle physiology?

Facilitate growth and repair of damaged tissue Signup and view all the answers

Which factor is crucial for achieving a response in VO2max for someone with a low initial VO2max?

Training at 40-50% max effort Signup and view all the answers

What is the dominant mechanism for heat loss at rest?

Radiation Signup and view all the answers

What happens to the muscle fiber when stimulation ends in the relaxation phase?

Calcium is pumped into the sarcoplasmic reticulum Signup and view all the answers

What adaptation results from strength training at the neuromuscular level?

Enhanced muscle fiber recruitment Signup and view all the answers

How does cold acclimatization affect shivering?

Later onset of shivering Signup and view all the answers

What component of the Exercise Volume formula is NOT part of the standard definition?

Type of exercise Signup and view all the answers

What physiological adaptation enhances cellular mechanisms during heat acclimation?

Higher cellular shock protein levels Signup and view all the answers

What is the main driver of late strength gains in muscle tissue?

Hypertrophy Signup and view all the answers

Which hormone is primarily responsible for promoting protein synthesis in response to resistance training?

Testosterone Signup and view all the answers

What happens to muscle fiber types during resistance training?

They change biochemically Signup and view all the answers

What is the effect of detraining on muscular strength?

Slow loss primarily due to neural adaptations Signup and view all the answers

Which factor is enhanced by mTOR activation in response to muscle stretch?

Protein synthesis Signup and view all the answers

What characterizes concurrent exercise training?

Combining resistance and endurance training Signup and view all the answers

What is the primary physiological change in muscle fibers as a result of resistance training?

Increase in myonuclei due to satellite cells Signup and view all the answers

Which of the following is true regarding the time course of retraining?

Strength and muscle size regain occurs rapidly within 6 weeks Signup and view all the answers

Study Notes

Exam I Content

Exercise responses to constant load/work rate: no change in intensity level over time
Plateau at steady-state / positive or negative drift
Exercise-induced hormesis: low/moderate dose of a harmful stressor (exercise), results in an adaptive response
Homeostasis: maintenance of relatively constant internal environment during resting conditions
Variables vary around a “set point”
Steady-State: constant internal environment during sub-maximal constant-load exercise, different than resting values
Biological control systems: maintain a parameter at a near “constant value”
Components: Sensor/receptor, Control center, Effector
Gain: degree to which a control system maintains homeostasis
Negative feedback systems: response reverses the initial disturbance in homeostasis
Positive feedback systems: response increases initial stimulus
Exercise as a test of homeostatic control: body doesn't maintain homeostasis during exercise
Sub-maximal: most systems reach & maintain steady-state
Maximal: cannot maintain steady-state, results in fatigue or cessation of exercise

Chapter 7

CNS: brain & spinal cord
PNS: afferent & efferent divisions
Afferent: sensory - receptors > CNS
Somatic sensory
Visceral sensory
Special sensory
Efferent: motor - CNS > effector organs
Somatic motor (voluntary)
Autonomic motor (involuntary)
Synaptic Transmission: how impulses are transmitted via neurotransmitters along axons
Resting membrane potential: the negative charge inside cells
Depolarization: when the membrane potential becomes less negative
Repolarization: process of restoring membrane potential back to resting state
Hyperpolarization: when the membrane potential becomes more negative
IPSP: cause hyperpolarization
EPSP: stimulate muscle contraction
Joint proprioceptors: provide CNS with body position information
Free nerve endings
Golgi-type receptors
Pacinian corpuscles
Muscle proprioceptors: (mechanoreceptors) provide info about movement
Muscle spindles respond to length changes
Golgi tendon organs: monitors tension
Somatic motor neurons: carries message to muscles
Motor unit: motor neuron and all it innervates

Chapter 8

Innervation ratio: number of fibers innervated by alpha motor neuron
Types of motor units: Type I, Type IIa, Type IIx
Size principle: smallest motor units recruited first
Microstructure of muscle fibers: Sarcoplasm, Myofibrils, Sarcomere, Sarcoplasmic reticulum, Transverse-tubules
Myonuclear domain
Satellite cells
Neuromuscular junction
Muscle contraction: excitation-contraction coupling
Excitation
Contraction-coupling
Relaxation
Muscle fiber types: IIx, Ila, I
Biochemical properties of muscle fibers: Oxidative capacity

Chapter 3

Energetics of contraction: slowed rate of ATP utilization, accumulation of Pi
Endergonic: requires energy, ATP > ADP
Exergonic: energy released, ADP > ATP
Oxidation-reduction reactions (redox)
Oxidation
Reduction
Hydrogen carriers: NAD, FAD
High energy products of metabolism

Anaerobic ATP Production

ATP-PC
Rapid Glycolysis
Aerobic ATP Production
Oxidative phosphorylation

Chapter 4: Exercise Metabolism

Relative oxygen: mL/kg/min
Absolute oxygen: L/min
Fick Equation: VO2 = Q x (a - v)O2 difference
Central component: Q (O2 delivery)
Peripheral component: (a-v)O2 diff (O2 extraction)
Maximal Oxygen Uptake (VO2max)
Gold standard: Graded exercise test
Values during Rest-to-Exercise Transition
ATP production
O2 requirements
PCr levels
Values during Incremental Exercise
ATP production

Chapter 10

Respiratory system functions: Gas exchange, Regulation of acid-base balance, Pressure differentials
Conducting zone
Transport air
Warm, humidify & filter air
Respiratory zone
Gas exchange
Alveolar dead space
Mechanics of Breathing
Inspiration
Expiration
Boyle's Law
Airway Resistance
Blood Flow to Lungs
Rest
Light Exercise
Heavy Exercise
Henry's Law

Chapter 11

Fick's Law of Diffusion: Rate of gas transfer
Tissue area
Diffusion coefficient
Difference in partial pressure
Partial Pressure Through Circulation: Alveolar gas, Blood entering lungs
O2 Transport in the Blood: Amount of O2
Oxyhemoglobin Dissociation Curve
O2 Transport in Muscle: Myoglobin
Effects of Temperature
CO2 Transport in Blood
Bicarbonate
CO2 Transport in Tissue

Chapter 12

Homeotherms
Heat Balance
Temperature control system
Role of the hypothalamus
Responses in core temperature
Overview of heat production and heat loss -Involuntary heat
Voluntary heat
Heat loss, 4 mechanisms

Ch 13

Principles of Training: Overload, Reversibility, Specificity
Stress and primary and secondary messengers
mRNA levels
Adaptation of endurance or aerobic exercise
Training-induced changes to VO2max

14

Muscular Strength
Muscular Endurance
Muscular Power
Muscular Fitness
Neuromuscular Adaptations
Hyperplasia
Hypertrophy
Neural Changes
RT-induced changes
Primary signal
Cellular mechanisms
Strength and CSA
Protein synthesis
Protein degradation
Mechanism for hypertrophy
Hormone actions

Chapter 15

Detraining vs. re-training
Neural changes
Effect of Muscle fiber changes
Time course of changes
Concurrent training

Additional Notes

Effects of altitude training on saturation of hemoglobin.
Living at high altitude → increase in red blood cell mass
Heat/Cold adaptations
Cardiovascular drift
Factors that decrease SV
Factors that regulate cardiac output

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Description

Explore the principles of exercise physiology concerning homeostasis and feedback mechanisms. This quiz covers steady-state conditions, biological control systems, and the effects of exercise on the body's internal environment. Test your knowledge on how the body adapts to constant load and maintains equilibrium during physical activity.