Muscle Tissue and Organization Lecture

15 question-and-answer flashcards covering key concepts about skeletal, cardiac, and smooth muscle structure, function, properties, and nomenclature.

What are the three types of muscle tissue in the human body?

Skeletal muscle, cardiac muscle, and smooth muscle.

Which muscle type is composed of long, cylindrical, multinucleated cells and operates mainly under voluntary control?

Skeletal muscle.

What structural feature produces the striated appearance seen in skeletal and cardiac muscle?

Highly organized actin and myosin filaments arranged into sarcomeres.

What specialized junctions connect cardiac muscle cells, enabling rapid electrical and mechanical coupling?

Intercalated discs that contain gap junctions and desmosomes.

Where is smooth muscle primarily found in the body?

In the walls of hollow organs (e.g., intestines, blood vessels, bladder, uterus, respiratory and urinary tracts).

Which universal muscle property is the ability to respond to a stimulus by generating an action potential?

Excitability.

In skeletal muscle, what is the correct hierarchical organization from largest to smallest?

Whole muscle → Fascicle → Muscle fiber → Myofibril → Myofilament.

What is the functional contractile unit of skeletal muscle, defined as the region between two Z-lines?

The sarcomere.

Which regulatory protein on the thin filament binds calcium to trigger skeletal muscle contraction?

Troponin.

How is contraction initiated in smooth muscle compared with skeletal muscle?

Calcium enters mainly from the extracellular space, binds to calmodulin (not troponin), and activates myosin for contraction.

Which muscle property describes the ability to recoil to resting length after being stretched?

Elasticity.

What is the name of the connective tissue layer that surrounds an individual skeletal muscle fiber?

Endomysium.

Which muscle type can maintain prolonged tone with minimal energy expenditure via latch bridges?

Smooth muscle.

What term refers to a muscle that opposes the action of the prime mover (agonist)?

Antagonist.

According to muscle-naming conventions, what does the prefix "biceps" indicate?

The muscle has two heads (two proximal origins).