Muscle System Overview

These flashcards cover essential terms and concepts from the muscle system lecture, aiding in the understanding of muscle anatomy, physiology, and function.

Muscular System

Made up of over 600 different muscles, nervous tissue, blood vessels, and consists of connective and muscle tissue.

Functions of the Muscular System

Includes creating movement, moving food and blood, producing heat, and providing protection to organs.

Connective Tissue Coverings

Four types include Deep Fascia, Epimysium, Perimysium, and Endomysium.

Tendons

Strands of flexible connective tissue that attach muscles to bones and pull on bones during muscle contraction.

Antagonistic Pairs

Muscles that work in pairs to cause smooth movements, with flexors bending and extensors straightening body parts.

Types of Muscle Activation

Voluntary (conscious control) and Involuntary (not under conscious control), including skeletal, cardiac, and smooth muscle.

Types of Muscle Tissue

Skeletal (movement), Cardiac (heart), and Smooth (digestive tract and blood vessels).

Sarcomere

Unit of contraction in muscle cells, where sliding filament theory explains how muscles contract.

Sliding Filament Theory

Neural impulse triggers calcium release which binds to troponin, allowing myosin heads to pull actin filaments, shortening the muscle.

ATP in Muscle Contraction

ATP provides energy for the flexing of myosin crossbridges during muscle contraction.

Oxygen Debt

The amount of oxygen required to restore pre-exercise muscle conditions and convert lactic acid back to glucose.

Heat Production

Muscle contraction generates heat, which helps maintain body temperature, but cellular respiration is only 40% efficient.

Excitation-Contraction Coupling

Process by which action potentials lead to calcium release and ultimately muscle contraction.

Myoglobin

Protein in muscle that binds and stores oxygen needed for aerobic cellular respiration during contraction.

Calcium's Role in Muscle Contraction

Calcium ions bind to troponin, exposing binding sites on actin, allowing interactions with myosin.

Energy Pathways for Muscle Contraction

ATP is derived from aerobic respiration, anaerobic glycolysis, and direct phosphorylation of creatine.

Fatigue in Muscles

Occurs when lactic acid accumulates during intense exercise as muscles exceed oxygen delivery capacity.

Detailed Functions of the Muscular System

Beyond movement, the muscular system is critical for posture maintenance, joint stability, heat production during thermogenesis, and protection of internal organs through muscular walls.

Muscle Fiber Types

Includes Type I fibers (slow-twitch; endurance activities), Type IIa fibers (fast-twitch; used for moderate intensity), and Type IIb fibers (fast-twitch; used for high-intensity activities).

Neurotransmitters in Muscle Contraction

Acetylcholine is released at the neuromuscular junction, initiating muscle contraction by triggering action potentials in muscle fibers.

Role of Energy Systems

The phosphagen system provides immediate energy through creatine phosphate, anaerobic glycolysis supplies energy for short bursts, while aerobic respiration fuels longer-duration activities.

Muscle Recovery Mechanisms

Recovery involves lactic acid removal, replenishment of glycogen stores, and repair of damaged muscle fibers through satellite cell activation.

Impact of Training on Muscle

Training induces muscular hypertrophy (increase in muscle size), improves muscular endurance, and enhances neuromuscular coordination, leading to increased strength.

Muscle Contractile Proteins

Key proteins include myosin (thick filament), actin (thin filament), tropomyosin (regulatory protein), and troponin (binds calcium).

Muscle Contraction Regulation

Regulated by the frequency of stimulation (summation of contractions) and the recruitment of motor units, affecting overall force output.

Muscle Adaptations to Exercise

Adjustments include increased mitochondrial density for aerobic capacity, improved capillary density for nutrient and oxygen delivery, and enhanced metabolic enzyme activity.