Muscular System: Histology and Physiology

A collection of flashcards covering key concepts from the muscular system, including types of muscle, their functions, structures, and physiological responses.

What are the types of muscle tissue?

Skeletal, Smooth, and Cardiac muscle.

Where is skeletal muscle located?

Attached to bones.

What is the shape of skeletal muscle cells?

Very long and cylindrical.

How many nuclei are in skeletal muscle cells?

Multiple nuclei, peripherally located.

What are the striations in skeletal muscle?

Yes, skeletal muscle has striations.

What type of control does skeletal muscle have?

Voluntary control.

Where is smooth muscle located?

Walls of hollow organs, blood vessels, eyes, glands, and skin.

What is the cell shape of smooth muscle?

Spindle-shaped.

How many nuclei are in smooth muscle cells?

Single, centrally located.

Does smooth muscle have striations?

No, smooth muscle does not have striations.

What type of control does smooth muscle have?

Involuntary and can be spontaneous.

Where is cardiac muscle found?

In the heart.

What is the shape of cardiac muscle cells?

Cylindrical and branched.

How many nuclei are in cardiac muscle cells?

Single, centrally located.

What is a key feature of cardiac muscle cells?

Intercalated disks join cells to one another.

Does cardiac muscle have striations?

Yes, cardiac muscle has striations.

What type of control does cardiac muscle have?

Involuntary.

What is the primary function of skeletal muscle?

Controlling body movement.

What functions do smooth muscles perform?

Moving food through the digestive tract, regulating blood vessel diameter, changing pupil size, and more.

What is the primary function of cardiac muscle?

Pumping blood.

What is a sarcomere?

The structural unit of muscle fibers.

What is the sliding filament model?

A theory explaining muscle contraction based on the sliding of actin and myosin filaments.

What initiates muscle contraction?

An action potential at the neuromuscular junction.

What is a motor unit?

A motor neuron and the muscle fibers it innervates.

What determines the strength of muscle contraction?

The number of motor units recruited and their firing rate.

What is the role of ATP in muscle contraction?

ATP provides energy for muscle contraction and relaxation.

What occurs during the relaxation phase of a muscle?

Calcium ions are pumped back into the sarcoplasmic reticulum.

What is the role of calcium ions in muscle contraction?

Calcium ions bind to troponin, facilitating the interaction between actin and myosin.

What do thick myofilaments primarily consist of?

Myosin.

What do thin myofilaments primarily consist of?

Actin.

What happens during cross-bridge formation?

Myosin heads attach to actin filaments.

What is the difference between isometric and isotonic contraction?

Isometric contraction does not change muscle length; isotonic does.

What is a tetanic contraction?

A sustained muscle contraction caused by a rapid series of stimuli.

What is muscle fatigue?

The decline in ability of a muscle to generate force.

How does aging affect muscle mass?

Aging often leads to a decrease in muscle mass and strength.

What are the characteristics of smooth muscle contraction?

Smooth muscle contracts more slowly and can sustain contractions longer than skeletal muscle.

What is a unique characteristic of cardiac muscle contraction?

Cardiac muscle can contract spontaneously and rhythmically.

What physiological adaptations occur in response to regular exercise?

Increased muscle mass, improved endurance, and enhanced metabolic efficiency.

How does the body regulate temperature during muscular activity?

Through increased blood flow to the skin and sweating.

What is the role of sensory receptors in muscle contraction?

They provide feedback on muscle length and tension to maintain posture and balance.

What role do gap junctions play in smooth muscle function?

They allow for coordinated contraction among smooth muscle cells.

What is muscular dystrophy?

A genetic disorder characterized by progressive weakness and degeneration of skeletal muscles.

What does the term 'plasticity' mean in reference to muscle?

The ability of muscle to adapt to new loads or conditions.

What is hypertrophy in muscle tissue?

Increase in muscle size due to strength training.

What is atrophy in muscle tissue?

The reduction in muscle size due to disuse or aging.

What is the role of satellite cells in muscle regeneration?

They contribute to muscle repair and growth after injury.

What is the function of the sarcoplasmic reticulum in muscle fibers?

It stores and releases calcium ions to initiate muscle contraction.

How do muscle fibers differ in terms of energy sources?

Type I fibers use aerobic respiration; Type II fibers use anaerobic respiration.

What are the effects of resistance exercise on skeletal muscles?

Increased muscle strength and size.

What is kinetic energy in the context of muscular contraction?

The energy of motion generated during muscle contraction.

What is the relationship between muscle length and tension generation?

There is an optimal muscle length for maximal tension generation.

What is the significance of lactic acid production during exercise?

It indicates anaerobic metabolism and can lead to muscle fatigue.

What types of membrane channels are important in muscle action potentials?

Voltage-gated sodium and calcium channels.

What physiological changes prepare the body for physical activity?

Increased heart rate, respiration rate, and blood flow to muscles.

How does the muscle's structure relate to its function?

Striated muscles allow for precise and controlled movements.

What is the primary energy pathway used during high-intensity exercise?

Anaerobic glycolysis.