Exam #3 Study Guide

These flashcards cover essential vocabulary and concepts related to the study of muscle physiology and neuromuscular interactions as outlined in the exam study guide.

Muscle contractions

Types of muscle contractions include isometric, isotonic concentric, and isotonic eccentric.

Action potential

An electrical signal that propagates along neurons and muscle fibers, crucial for muscle contraction.

Refractory period

The time period following an action potential during which a neuron or muscle fiber cannot fire another action potential.

Neuromuscular junction

The synapse or junction between a motor neuron and a skeletal muscle fiber.

Sodium channels

Proteins that allow sodium ions to enter a cell; play a crucial role in initiating and propagating action potentials.

Myofibrils

The long, thread-like structures within muscle fibers composed of actin and myosin filaments.

Ligand-gated channels

Ion channels that open in response to the binding of a chemical messenger (ligand).

Isometric contraction

A type of muscle contraction where the muscle generates force without changing its length.

Types of muscle fibers

Slow twitch (Type I) and fast twitch (Type II) fibers, differing in endurance and contraction speed.

Electrochemical gradient

The combined gradient of chemical concentration and electrical charge that affects ion movement across membranes.

Muscle fatigue

The decline in the ability of a muscle to generate force, often due to energy depletion.

Crossbridge cycle

The process of myosin heads attaching to actin filaments, pulling them, and releasing during muscle contraction.

Endurance exercises

Training aimed at improving the efficiency and capacity of the cardiovascular and muscular systems.

Motor units

A motor neuron and all the muscle fibers it innervates; different types can vary in size and function.

Synaptic transmission

The process by which a signal is transmitted across a synapse; involves neurotransmitter release and receptor binding.

Tetanus

A state of sustained muscle contraction that occurs when the muscle is stimulated repeatedly without relaxation.

Electrolyte imbalances

Conditions such as hypernatremia or hypokalemia that affect nerve function and muscle contraction.

Calcium ions

Essential for muscle contraction; release from the sarcoplasmic reticulum triggers contraction mechanisms.

Agonist vs. antagonist

Agonist: a substance that activates a receptor. Antagonist: a substance that inhibits a receptor's action.

Neurotransmitter removal

Processes including diffusion, enzymatic breakdown, and reuptake that terminate the action of neurotransmitters in the synapse.

Threshold potential

The critical level to which a membrane potential must be depolarized to initiate an action potential.

Muscle relaxation

The process of muscle fibers returning to their resting state after contraction.

Muscle contraction types

The main types of muscle contractions include isometric, isotonic concentric, and isotonic eccentric.

Resting membrane potential

The difference in electrical charge inside and outside a neuron at rest, typically around -70 mV.

Fast-twitch muscle fibers

Muscle fibers that generate force quickly but fatigue rapidly, suitable for short bursts of activity.

Slow-twitch muscle fibers

Muscle fibers that are more resistant to fatigue and are ideal for endurance activities.

Muscle hypertrophy

The increase in the size of muscle fibers as a result of training, often through resistance exercises.

Muscle atrophy

The decrease in muscle mass and strength due to disuse, disease, or aging.

Muscle spindles

Sensory receptors located within muscles that detect changes in muscle length and rate of stretch.

Golgi tendon organs

Sensory receptors that sense tension in the tendons and prevent excessive force in muscle contractions.

Motor learning

The process of improving motor skills through practice and experience.

Cross-bridging in muscles

The interaction between actin and myosin filaments that is critical for muscle contraction.