Animal Physiology - Skeletal Muscle Review

These flashcards cover key concepts from the lecture on skeletal muscle physiology, including types of muscles, mechanisms of contraction, and ATP regeneration.

What are skeletal muscles composed of?

Skeletal muscles consist of bundles of longitudinally arranged muscle fibers (cells).

What is the longest muscle in the human body?

The Sartorius is the longest muscle in the human body.

What is the largest muscle in the human body?

The Gluteus Maximus is the largest muscle in the human body.

What is the smallest muscle in the human body?

The Musculus stapedius is the smallest muscle in the human body.

What is a sarcomere?

A sarcomere is the functional unit of striated muscle, consisting of thick and thin myofilaments.

What are myofibrils?

Myofibrils are the basic rod-like units of a muscle cell containing the contractile filaments (myosin and actin).

What is the role of calcium ions in muscle contraction?

Calcium ions regulate muscle contraction by interacting with troponin and tropomyosin.

What is excitation-contraction coupling?

Excitation-contraction coupling is the process by which an action potential leads to muscle contraction through the interactions of transverse tubules and the sarcoplasmic reticulum.

What are the three principal mechanisms of ATP regeneration in vertebrate muscle?

The three principal mechanisms are phosphagen use, anaerobic glycolysis, and aerobic catabolism.

What distinguishes tonic smooth muscles from phasic smooth muscles?

Tonic smooth muscles maintain contractile force for long periods, while phasic smooth muscles produce rhythmic or intermittent activity.

How does cardiac muscle differ from skeletal muscle?

Cardiac muscle cells are branched, usually uninucleate, and connected by intercalated discs, while skeletal muscle cells are long and multinucleated.

What is the function of intercalated discs in cardiac muscle?

Intercalated discs provide electrical coupling and mechanical strength, allowing synchronized contraction of heart cells.

What is tetanus in muscle physiology?

Tetanus is a state of maximum contraction occurring when muscle fibers are stimulated so rapidly that they do not relax.

What regulates smooth muscle contraction?

Smooth muscle contraction is regulated by the phosphorylation of myosin light chains instead of troponin, involving calcium and calmodulin.

What is the role of myosin and actin in muscle contraction?

Myosin and actin interact through cross-bridges to produce muscle contraction through sliding filament mechanism.

What governs the rate of cross-bridge formation in muscle fibers?

The rate of ATP hydrolysis governs the rate of cross-bridge formation in muscle fibers.