Overview of Muscle Tissues

Flashcards to assist in studying and understanding the muscular system, muscle types, contraction processes, and muscle function.

What are the primary functions of muscles?

Muscles are responsible for body movements, stabilizing joints, and generating heat.

How do muscles generate force?

Muscles generate force required for movement by contracting, where proteins inside muscle fibers overlap.

What does muscle contraction enable other than whole body movements?

Muscle contraction is needed to move substances inside the body, such as air in lungs and food in digestion.

Why are muscles referred to as 'machines' of the body?

Because they are responsible for all body movements.

What is the Latin word for muscle and its meaning?

The Latin word is 'mus,' meaning 'little mouse.'

What is skeletal muscle also known as?

Skeletal muscle is known as striated muscle and voluntary muscle.

What is the unique characteristic of muscle tissue?

The essential function of muscle tissues is to contract or shorten.

What are the three types of muscle tissue?

The three types are skeletal, smooth, and cardiac.

What distinguishes skeletal muscle from cardiac and smooth muscle?

Skeletal muscle is voluntary, while smooth and cardiac muscles are involuntary.

What is the connective tissue sheath surrounding a single muscle fiber called?

Endomysium.

What comprises a fascicle?

A fascicle is a bundle of muscle fibers wrapped in perimysium.

How is the entire muscle wrapped?

The entire muscle is wrapped in a connective tissue sheath called epimysium.

What attaches muscles to bones?

Tendons attach muscles to bones.

What is an aponeurosis?

An aponeurosis is a sheetlike connective tissue that attaches muscles to other structures.

What shape are skeletal muscle fibers?

Skeletal muscle fibers are large, cigar-shaped, and multinucleate.

What are myofibrils?

Myofibrils are long ribbonlike organelles that fill the sarcoplasm of muscle fibers.

What do striations in skeletal muscle indicate?

Striations indicate the orderly arrangement of myofilaments within the myofibrils.

What are thick and thin filaments made of?

Thick filaments are primarily made of myosin and thin filaments are made of actin.

What is the basic contractile unit of skeletal muscle?

The sarcomere.

What is the role of calcium ions in muscle contraction?

Calcium ions trigger muscle contraction by enabling the binding of myosin to actin.

What is the sliding filament theory?

The theory that muscle contractions occur as myofilaments slide past one another, causing sarcomeres and overall muscles to shorten.

Which type of muscle tissue is involuntary and lacks striations?

Smooth muscle.

Where is cardiac muscle found?

Cardiac muscle is found only in the heart.

What is the primary function of cardiac muscle?

To pump blood through the circulatory system.

Define graded muscle response.

Graded muscle response refers to the varying degrees of muscle contraction strength based on stimulus frequency and muscle fiber recruitment.

What does isotonic contraction mean?

Isotonic contraction is when muscle tension remains constant while the muscle changes length, allowing for movement.

What does isometric contraction mean?

Isometric contraction is when muscle tension increases but the muscle does not change length, preventing movement.

What is muscle tone?

Muscle tone is the state of partial contraction that maintains muscle firmness and readiness for action.

What are antagonistic muscles?

Muscles that oppose the action of another muscle are referred to as antagonistic muscles.

What is the role of synergist muscles?

Synergist muscles assist the primary mover in performing a movement.

What do fixator muscles do?

Fixator muscles stabilize the origin of the prime mover so that optimal tension can be used to move the insertion bone.

What changes occur in muscle during aging?

With aging, muscle tissue decreases, connective tissue increases, and muscle strength declines.

Why is regular exercise important for muscles?

Regular exercise helps maintain muscle strength, size, and overall physical health.

What is 'oxygen deficit'?

Oxygen deficit refers to a condition during intense exercise when the body cannot supply enough oxygen for aerobic ATP production.

What is the direct source of energy for muscle contraction?

ATP (adenosine triphosphate) is the direct source of energy for muscle contraction.

What is lactic acid and how is it produced?

Lactic acid is produced during anaerobic metabolism when pyruvic acid accumulates due to insufficient oxygen.

What is muscle fatigue?

Muscle fatigue is the condition where muscles can no longer contract effectively due to depletion of energy reserves or accumulation of metabolic by-products.

What is hypertrophy in muscles?

Hypertrophy refers to an increase in muscle size due to increased workload and resistance.

How does aerobic exercise benefit muscles?

Aerobic exercise enhances muscle endurance and efficiency, increasing blood supply and mitochondrial density.

What is the effect of resistance training on muscles?

Resistance training increases muscle size and strength by enlarging individual muscle fibers.

What role do tendons play in muscle action?

Tendons attach muscles to bones, enabling movement when muscles contract.

What determines the strength of a muscle contraction?

The strength of a muscle contraction is determined by the number of fibers recruited and the frequency of stimulation.

What happens at the neuromuscular junction?

At the neuromuscular junction, nerve impulses stimulate muscle fibers via the release of acetylcholine.

What causes the striated appearance in skeletal muscle?

The precise arrangement of thick and thin filaments within sarcomeres results in striations.

What must happen for muscle relaxation to occur?

Calcium ions must be pumped back into the sarcoplasmic reticulum, and myosin-binding sites must be blocked.

What does the term 'myofibril' refer to?

Myofibrils are the basic rod-like units in a muscle fiber that contract during muscle contraction.

What triggers the release of calcium ions in muscle cells?

An action potential traveling along the sarcolemma triggers calcium ion release from the sarcoplasmic reticulum.

What is the role of action potential in muscle contraction?

The action potential generates depolarization, leading to muscle contraction.

What is an antagonist's role during muscle movement?

Antagonists relax and stretch while the prime mover contracts to facilitate smooth movement.

What is the significance of muscle fiber orientation?

The orientation affects the range of motion and force generation of the muscle.

What is an example of a muscle that performs isotonic contraction?

Bending the elbow or lifting weights are examples of isotonic contraction.

What is a common characteristic of smooth muscle?

Smooth muscle is non-striated and involuntary.

What is the primary energy pathway during intense exercise?

Anaerobic glycolysis is the primary energy pathway to produce ATP during intense exercise.

What happens to muscle fibers when they are not used?

Unused muscle fibers can atrophy, leading to loss of strength and mass.

What must occur after an oxygen deficit?

The body must restore oxygen levels to remove lactic acid and replenish energy stores.

What does 'myopathy' refer to?

Myopathy refers to any disease or damage affecting muscle tissue.

What is the importance of the sarcoplasmic reticulum?

The sarcoplasmic reticulum stores calcium ions needed for muscle contraction.

Why is muscle mass important to overall health?

Muscle mass contributes to metabolism, mobility, and functional capacity, impacting overall health.

How does the body recover from muscle fatigue?

Recovery involves resuming normal oxygen intake and clearing metabolic waste from muscles.

How does the body ensure muscles maintain tone?

The nervous system continuously stimulates subsets of motor units to maintain muscle tone even at rest.

What are the three main function of the muscular system?

The muscular system is responsible for movement, maintaining posture, and generating heat.

What is the definition of a motor unit?

A motor unit consists of a motor neuron and all the muscle fibers it innervates.

How can muscle contractions be graded?

Through altering the frequency of stimulation and the number of motor units activated.

What are the muscle's contractile proteins?

The contractile proteins are actin (thin) and myosin (thick).

What does muscle hypertrophy result from?

Muscle hypertrophy results from increased tension and resistance during strength training.

What is sarcolemma?

Sarcolemma is the plasma membrane surrounding a muscle fiber.

What is the role of myosin heads during contraction?

Myosin heads bind to actin to form cross-bridges necessary for muscle contraction.

How do muscles maintain posture?

Muscles maintain posture by making continuous adjustments to counteract gravity.

What function do the intercalated discs serve in cardiac muscle?

Intercalated discs allow electrical impulses to spread quickly between cardiac muscle cells.

What happens to muscle fibers during resistance training?

Resistance training increases the size and strength of muscle fibers.

What is the muscle fiber's functional unit called?

The functional unit of a muscle fiber is the sarcomere.

What are the physiological adaptations of muscles to regular training?

Increased oxidative capacity, higher muscle glycogen stores, and improved neuromuscular coordination.