Exercise Physiology and Neuromuscular Control Review

Vocabulary flashcards covering neuromuscular concepts, motor unit recruitment, autonomic nervous system pathways, and endocrine responses to exercise.

Cerebellum

The brain center involved in correcting errors during fast movements.

Basal ganglia

The brain center involved in initiating movement that has low dopamine in parkinston’s disease.

Size principle

The principle that recruits motor units from small to large as force demand increases.

Rate coding

The mechanism that allows muscle force to continue increasing through a higher firing frequency after motor unit recruitment is complete.

Muscle spindle

The sensory receptor that detects rapid stretch and initiates the reflex causing the lower leg to kick forward when the patellar tendon is tapped.

Preganglionic sympathetic neuron

A sympathetic neuron emerging from the spinal cord that releases acetylcholine ($\text{ACh}$).

Postganglionic sympathetic neuron to the heart

A sympathetic neuron that releases norepinephrine ($\text{NE}$) to increase heart rate.

Sweat glands (sympathetic innervation)

A sympathetic nervous system exception that receives acetylcholine ($\text{ACh}$) rather than norepinephrine.

Plasma free fatty acid (FFA) reduction mechanisms during heavy exercise

Factors reducing free fatty acid availability at high intensity, including lactate promoting FFA re-esterification, $H^+$ inhibiting hormone-sensitive lipase (HSL), and reduced adipose blood flow.

Intracellular control of glycogenolysis

The local, intracellular regulation within contracting muscle that primarily drives glycogen breakdown rather than systemic hormonal control alone.

Hormonal response at $40\%\,VO_2\text{ max}$

An exercise intensity state in which cortisol will likely decrease and growth hormone (GH) shows a minimal or very modest increase.

Hormonal response at $80\%\,VO_2\text{ max}$

An exercise intensity state in which both cortisol and growth hormone (GH) elevate significantly.

Lactate inhibition of hormone-sensitive lipase (HSL)

The mechanism that contributes most to the decrease in free fatty acid (FFA) utilization during intense exercise despite elevated lipolytic hormones.

Propranolol glycogenolysis test

The pharmacological blocking of β-adrenergic receptors that fails to completely prevent muscle glycogen breakdown, demonstrating that plasma epinephrine is not the sole initiator of glycogenolysis.

Fast-acting hormones

The pair of hormones classified as rapidly acting in the context of exercise, consisting of epinephrine and norepinephrine.

Blood glucose regulation at $70\%\,VO_2\text{ max}$

The combination of decreased insulin and increased glucagon that helps maintain blood glucose during a $30$-minute run.

Post-training catecholamine response at identical absolute speed

The decrease in plasma epinephrine ($\text{E}$) and norepinephrine ($\text{NE}$) levels during exercise following a $12$-week endurance program because the relative intensity ($\%VO_2\text{ max}$) is lower.

Cortisol kinetics during low-intensity exercise

The physiological balance below threshold intensity where plasma cortisol concentration stays the same or decreases primarily because cortisol removal exceeds cortisol secretion.

Dual control of muscle glycogen breakdown

The two primary regulatory factors responsible for glycogenolysis during exercise: epinephrine–cyclic AMP and $Ca^{2+}$–calmodulin.