Types of Muscular Tissue and Muscle Physiology

Flashcards focusing on key concepts and terminology related to muscular tissue and physiology.

Skeletal Muscle

Muscle attached to bones; striated and under voluntary control.

Cardiac Muscle

Muscle found only in the heart; striated and involuntary.

Smooth Muscle

Muscle found in walls of hollow organs; non-striated and involuntary.

Voluntary Control

Muscle contractions that are consciously controlled.

Involuntary Control

Muscle contractions that occur automatically without conscious control.

Striated Muscle

Muscle that has a striped appearance due to its fibers.

Non-Striated Muscle

Muscle that does not have a striped appearance.

Autorhythmicity

The ability of cardiac muscle to contract rhythmically without external stimuli.

Pacemaker

Cells in the heart that set the rhythm of contractions.

Somatic Nervous System

Part of the nervous system responsible for voluntary control of skeletal muscles.

Autonomic Nervous System

Part of the nervous system that controls involuntary body functions.

Thermogenesis

Production of heat, primarily through muscle contractions.

Excitability

Ability of muscle tissue to respond to stimuli.

Contractility

Capability of muscle fibers to shorten and exert force.

Extensibility

Ability of muscle tissue to stretch without damage.

Elasticity

Ability of muscle tissue to return to its original shape after stretching.

Epimysium

The outermost connective tissue layer surrounding a muscle.

Perimysium

Connective tissue that surrounds bundles of muscle fibers.

Endomysium

Connective tissue that surrounds individual muscle fibers.

Fascia

Connective tissue that surrounds and supports muscles and organs.

Tendon

Connective tissue that attaches muscles to bones.

Aponeurosis

Flat sheet-like connective tissue anchoring muscles.

Myofibrils

Threadlike structures inside muscle fibers that cause contraction.

Sarcoplasmic Reticulum (SR)

Network around myofibrils that stores calcium ions.

Calcium Ions (Ca²⁺)

Minerals that trigger muscle contraction when released.

Action Potential

Electrical signal that initiates muscle contraction.

Sliding Filament Mechanism

Theory explaining how muscles contract by filaments sliding past each other.

Myosin

Thick filament protein that pulls actin during muscle contraction.

Actin

Thin filament protein involved in muscle contraction.

Cross-Bridge Formation

When myosin heads connect to actin filaments during contraction.

Power Stroke

The action of myosin pulling actin during muscle contraction.

Muscle Fiber

Single cell of muscle tissue that can contract.

T Tubules

Inward extensions of the muscle fiber membrane that aid in action potential propagation.

Sarcolemma

The plasma membrane surrounding a muscle fiber.

Neuromuscular Junction (NMJ)

The synapse between a motor neuron and a muscle fiber.

Acetylcholine (ACh)

Neurotransmitter released at the NMJ to initiate muscle contraction.

Muscle Action Potential

Electrical signal that travels along the sarcolemma to trigger contraction.

End-Plate Potential

Depolarization of the muscle fiber membrane at the NMJ following ACh binding.

Botulinum Toxin

Blocks ACh release leading to muscle paralysis.

Creatine Phosphate

Energy-rich molecule that quickly regenerates ATP in muscles.

Anaerobic Respiration

ATP production without oxygen during short bursts of activity.

Aerobic Respiration

ATP production with oxygen, used for prolonged activities.

Lactic Acid

Produced during anaerobic respiration when oxygen is low.

Muscle Fatigue

Inability of muscle to maintain force after prolonged exertion.

Oxygen Debt

Extra oxygen required after exercise to restore normal physiological conditions.

Motor Unit

One motor neuron and all the muscle fibers it controls.

Twitch Contraction

A single, quick contraction cycle of muscle fibers in response to a stimulus.

Wave Summation

Increased muscle contraction strength when stimuli occur before relaxation.

Fused Tetanus

Steady, sustained muscle contraction with no relaxation phases.

Recruitment

Activation of more motor units to increase muscle contraction strength.

Muscle Tone

Slight tension in muscles at rest produced by involuntary contractions.

Isotonic Contraction

A contraction where muscle length changes while tension remains constant.

Isometric Contraction

A contraction where muscle tension increases but length does not change.

Slow Oxidative Fibers (Type 1)

Muscle fibers that use aerobic respiration and resist fatigue.

Fast Glycolytic Fibers (Type 2B)

Muscle fibers primarily using anaerobic glycolysis, prone to fatigue.

Fast Oxidative Fibers (Type 2A)

Muscle fibers that can use both aerobic and anaerobic respiration.

Hypertrophy

Increase in muscle size due to resistance training.

Aging Effects on Muscles

Loss of muscle mass and strength with age, often replaced by fat.

Muscle Regeneration

The ability of muscle tissue to repair and regenerate after injury.

Satellite Cells

Stem cells that assist in muscle repair and regeneration.

Stress-Relaxation Response

Ability of smooth muscle to adapt to stretching.

Calmodulin

Regulatory protein in smooth muscle that activates contraction.

Neuromuscular Disorders

Conditions that affect the ability of nerves and muscles to communicate.

Muscle Fiber Types Distribution

The mix of slow and fast twitch fibers determines muscle behavior.

Exercise Adaptation

Changes in muscle characteristics from regular physical activity.

Recovery Oxygen Uptake

Increased oxygen consumption following exercise for recovery processes.

Endurance Training Effects

Increased muscle efficiency and stamina through aerobic exercise.

Resistance Training Effects

Increased muscle strength and size through anaerobic exercise.

Tendonitis

Inflammation of tendons due to overuse or injury.

Myopathy

Disease affecting muscle tissue, leading to weakness.

Strain

Injury to a muscle or tendon due to overstretching.

Sprain

Injury to ligaments caused by overstretching or tearing.

Electromyography (EMG)

A test to assess the electrical activity of muscles.

Muscle Contraction Steps

Sequence of events from action potential to muscle shortening.

Function of Muscular System

Movement, maintaining posture, and producing heat.

Role of Myoglobin

Oxygen-binding protein that stores oxygen in muscles for energy.

Blood Supply to Muscles

Arteries provide oxygen and nutrients; veins remove wastes.

Importance of Calcium in Muscle

Essential for initiating contraction and muscle function.

Refractory Period

Period when a muscle fiber is unresponsive to stimuli.

Smooth Muscle Characteristics

Involuntary, non-striated, capable of sustained contractions.

Cardiac vs. Skeletal Muscle

Cardiac muscle has intercalated discs; skeletal muscle does not.

Function of Intercalated Discs

Help synchronize heart contraction and communicate quickly.

Exercise and Fiber Type Shift

Endurance training can convert FG fibers into FOG fibers.

Role of Stretching

Increases flexibility and range of motion by elongating muscles.

Recovery from Muscle Fatigue

Involves replenishing oxygen, ATP, and clearing lactic acid.

Factors Affecting Muscle Performance

Include fiber type, training, nutrition, and hydration.

Role of ATP in Muscle Contraction

Provides energy necessary for myosin head movement during contraction.

Muscle Damage Repair

Process involving satellite cells and inflammatory response to restore muscle.