Muscular Tissue Overview

These flashcards cover key concepts regarding muscular tissue, its types, structure, functions, contraction mechanisms, and related physiological concepts.

What are the three types of muscular tissue?

Skeletal, Cardiac, and Smooth (visceral) muscle.

What is the function of skeletal muscle tissue?

To move bones.

How is cardiac muscle characterized?

Striated with intercalated discs and involuntary control.

What is a key feature of smooth muscle?

It is non-striated and controls various organ functions involuntarily.

What is the role of a tendon?

Connects muscle to bone.

What is the structure surrounding a fascicle called?

Perimysium.

How do muscle fibers form?

From the fusion of myoblasts.

What is a key component of a muscle fiber structure?

Myofibrils.

What is the function of the sarcoplasmic reticulum?

To store calcium ions for muscle contraction.

What does the sliding filament mechanism involve?

Myosin pulls on actin causing muscle contraction.

What is a sarcomere?

The basic contractile unit of muscle fibers.

What proteins are involved in muscle contraction?

Myosin and Actin.

What does the term 'muscle action potential' refer to?

An electrical signal that triggers muscle contraction.

What occurs at the neuromuscular junction (NMJ)?

Release of ACh, triggering muscle action potential.

What happens during muscle relaxation?

Calcium ions are pumped back into the sarcoplasmic reticulum.

What is muscle fatigue?

The inability to maintain force of contraction after prolonged activity.

What contributes to oxygen debt?

Replenishing CP stores and converting lactate to pyruvate post-exercise.

What is a motor unit?

A somatic motor neuron and the muscle fibers it innervates.

What is a twitch contraction?

The brief contraction of all muscle fibers in a motor unit in response to a single action potential.

What happens during wave summation?

A second action potential triggers muscle contraction before the first has finished.

What is the difference between isotonic and isometric contraction?

Isotonic changes muscle length; isometric does not.

What characterizes slow oxidative muscle fibers?

They have high endurance and are fatigue-resistant.

What does hypertrophy of muscle fibers refer to?

Increased muscle cell size due to increased workload.

What happens to muscle tissue with aging?

Muscle strength and flexibility decrease; fibrous connective tissue increases.

What is the role of ACh at the NMJ?

To bind to receptors and generate a muscle action potential.

What is the link between muscle action potentials and the sliding filament mechanism?

Muscle action potentials trigger calcium release, which facilitates the sliding filament mechanism.

What is the function of creatine phosphate in muscles?

To rapidly regenerate ATP during short bursts of activity.

What causes the Z discs to move toward each other during muscle contraction?

The sliding of thin filaments past thick filaments.

How do somatic motor neurons communicate with muscle fibers?

Through the release of neurotransmitters at the NMJ.

What role does troponin play in muscle contraction?

It binds calcium ions and facilitates the exposure of myosin-binding sites on actin.

How is muscle tone generated?

Through weak, involuntary contractions of motor units.

What happens during the latent period of a muscle contraction?

There is a delay before muscle fibers respond to a stimulus.

What is the main function of myoglobin in muscles?

To store oxygen for muscle contraction.

What type of muscle is found in the heart?

Cardiac muscle.

How does smooth muscle differ from skeletal muscle in terms of contractions?

Smooth muscle contractions start slowly and last longer.

What occurs during a power stroke in muscle contraction?

Myosin heads pull thin filaments toward the center of the sarcomere.

What determines the force of muscle contraction?

The number of activated motor units.

What are the consequences of muscle aging?

Decreased strength and flexibility, with reflexes slowing.

What physiological process occurs when Ca²+ is released from the sarcoplasmic reticulum?

Initiates muscle contraction.

What is meant by muscle hypertrophy?

Increase in muscle mass or size.

What is the role of ATP in muscle contraction?

Provides energy for the contraction cycle.

How does fusion of myoblasts contribute to muscle development?

Forms multinucleated skeletal muscle fibers.

What process does anaerobic glycolysis contribute to?

Rapid ATP production during lack of oxygen.

What happens to lactic acid during heavy exercise?

It accumulates and can contribute to muscle fatigue.

What anatomical feature distinguishes cardiac muscle from skeletal muscle?

Intercalated discs.

What is the primary purpose of the perimysium?

Surrounds fascicles within a muscle.