Exercise Physiology & Neuro-Muscular Review (Ch. 2-4, 7)

A comprehensive set of flashcards covering homeostasis, metabolism, energy systems, nervous and muscular physiology, and exercise adaptations for exam preparation.

What is the definition of homeostasis?

Maintaining a constant and normal internal environment at rest.

How does steady state differ from homeostasis?

A physiological variable remains stable during stress (e.g., exercise) but not at its normal resting value.

What feedback mechanism do most physiological control systems use?

Negative feedback.

In negative feedback, how is the initial disturbance handled?

It is reversed to restore normal conditions.

During blood glucose regulation, which hormone lowers high blood sugar?

Insulin.

What happens if insulin is ineffective, as in diabetes?

Glucose stays in the blood, causing hyperglycemia.

Give two examples of homeostatic regulation besides glucose control.

Temperature regulation (sweating/shivering) and pH balance via lungs/cardiovascular system.

What causes Type 1 diabetes?

Autoimmune destruction of insulin-producing beta cells.

What is the primary problem in Type 2 diabetes?

Tissues become resistant to insulin despite its presence.

Define adaptation in physiology.

Long-term structural and functional changes that help maintain homeostasis.

Define acclimation.

Short-term physiological adjustment to an environmental stress.

Give two examples of acclimation.

Heat adaptation increases sweating efficiency; high-altitude training raises red blood cell count.

Which signaling pathway sends hormones through the bloodstream to distant cells?

Endocrine signaling.

In which signaling type does a cell communicate with itself?

Autocrine signaling.

What is metabolism?

The sum of all chemical reactions in the body.

Differentiate anabolism and catabolism.

Anabolism synthesizes molecules; catabolism breaks them down.

Which reaction type requires energy input?

Endergonic reaction.

Which reaction type releases energy?

Exergonic reaction.

What are coupled reactions?

An exergonic reaction drives an endergonic reaction.

Define oxidation in biochemical terms.

Loss of electrons (or hydrogen).

Define reduction.

Gain of electrons (or hydrogen).

When NAD+ gains electrons, what molecule is formed?

NADH.

When FAD gains electrons, what molecule is produced?

FADH2.

List the three components of ATP.

Adenine, ribose, and three phosphate groups.

What reaction releases energy from ATP?

ATP → ADP + Pi.

Name the three energy systems that resynthesize ATP.

Phosphagen system, glycolysis, and oxidative phosphorylation.

Which energy system uses phosphocreatine for immediate ATP?

Phosphagen (ATP-PC) system.

Where does glycolysis occur?

In the cytoplasm.

What is the end product of glycolysis when oxygen is absent?

Lactic acid.

How many net ATP are produced per glucose via glycolysis?

2 ATP.

Into what molecule is pyruvate converted before entering the Krebs cycle?

Acetyl-CoA.

Name the two electron carriers generated by the Krebs cycle.

NADH and FADH2.

What is the final electron acceptor in the electron transport chain?

Oxygen.

What does beta-oxidation produce from fatty acids?

Acetyl-CoA.

Which pathway converts certain amino acids to glucose?

Gluconeogenesis.

What temperature range is optimal for most enzymes?

37–40 °C.

How does intense exercise–induced acidosis affect enzymes?

Low pH reduces enzyme function.

Approximately how many ATP are yielded from complete oxidation of one glucose molecule?

About 32 ATP.

Roughly how many ATP come from oxidation of one fatty acid such as stearic acid?

About 106 ATP.

What are free radicals?

Molecules with unpaired electrons that cause oxidative stress.

What substances neutralize free radicals?

Antioxidants.

For how long does the ATP-PC system dominate energy supply?

About 1–5 seconds.

During what duration is glycolysis the primary ATP source?

Approximately 6–120 seconds.

After 1–4 minutes of exercise, which energy system predominates?

Aerobic metabolism via Krebs cycle and ETC.

Define VO₂ max.

Maximum oxygen uptake during intense exercise.

What is oxygen deficit?

Early-exercise period when ATP demand exceeds aerobic supply.

What is EPOC?

Elevated post-exercise oxygen consumption to restore homeostasis.

At what VO₂ max percentage does lactate threshold occur in untrained people?

50–60 % VO₂ max.

In trained endurance athletes, lactate threshold occurs at what VO₂ max percentage?

65–80 % VO₂ max.

Name one cause of lactate accumulation during exercise.

Low muscle oxygen, recruitment of fast-twitch fibers, accelerated glycolysis, or reduced lactate removal.

Does lactate cause muscle soreness?

No; soreness is due to microscopic muscle damage.

According to the crossover concept, which fuel increases with higher exercise intensity?

Carbohydrate.

What training adaptation most improves aerobic metabolism and lowers lactate buildup?

Increased mitochondrial volume.

How quickly is lactate typically cleared from blood after exercise?

Within about 60 minutes.

What is the Cori cycle?

Conversion of lactate to glucose in the liver.

What two structures compose the central nervous system?

Brain and spinal cord.

Which PNS division brings sensory information to the CNS?

Afferent (sensory) division.

Name the neuron structures that receive impulses.

Dendrites.

What glial cells form the myelin sheath in the PNS?

Schwann cells.

What does the Na⁺/K⁺ pump move and in which directions?

3 Na⁺ out and 2 K⁺ in.

During an action potential, which ion influx causes depolarization?

Na⁺.

Which phase restores negativity inside the neuron?

Repolarization via K⁺ exit.

What type of postsynaptic potential increases action-potential likelihood?

Excitatory Postsynaptic Potential (EPSP).

Which proprioceptor senses muscle stretch?

Muscle spindle.

Which proprioceptor monitors tension and prevents excessive force?

Golgi tendon organ.

Define motor unit.

A motor neuron and all the muscle fibers it innervates.

Which motor units are recruited first according to the size principle?

Type I (slow-twitch) small units.

What brain region coordinates movement and balance?

Cerebellum.

Which autonomic division is known for “fight or flight”?

Sympathetic nervous system.

Which neurotransmitter is released by sympathetic postganglionic neurons?

Norepinephrine.

List one benefit of regular exercise to brain health.

Increased blood flow, neurogenesis, or reduced risk of dementia/depression.

What is the primary function of skeletal muscles related to movement?

Force production for movement and breathing.

Name the connective tissue layer surrounding an entire muscle.

Epimysium.

What stem cells aid muscle growth and repair?

Satellite cells.

Which two contractile proteins form cross-bridges?

Actin and myosin.

What organelle releases Ca²⁺ to trigger contraction?

Sarcoplasmic reticulum.

Which structure conducts action potentials deep into a muscle fiber?

T-tubules.

Which sarcomere band contains only thin filaments?

I-band.

What happens to the H-zone during full muscle contraction?

It disappears.

What neurotransmitter is released at the neuromuscular junction?

Acetylcholine.

During the power stroke, ATP is hydrolyzed into what products?

ADP and Pi.

Why is ATP also required for muscle relaxation?

It detaches myosin from actin and powers Ca²⁺ reuptake.

What condition occurs when no ATP is available after death?

Rigor mortis.

How does thixotropy affect muscle stiffness after prolonged sitting?

Muscles feel stiff but loosen with movement.

What reflex automatically withdraws a limb from a painful stimulus?

Withdrawal reflex.

What is neural fatigue theory?

Suggests exercise fatigue results from reduced neurotransmitter availability causing lower motor output.