Muscle Anatomy and Physiology – Lecture Review

These Q&A flashcards cover the essential concepts from the lecture: muscle tissue types and their characteristics, skeletal muscle micro-anatomy, the Sliding Filament Theory, neuromuscular junctions, and action potentials.

What are the three major types of muscle tissue?

Skeletal muscle, cardiac muscle, and smooth muscle.

Where is skeletal muscle primarily found in the body?

Attached to bones or to the skin of the face.

Which muscle type is found only in the walls of the heart?

Cardiac muscle.

In what structures is smooth muscle predominantly located?

Walls of hollow organs and blood vessels.

How is skeletal muscle contraction regulated?

Voluntarily through control by the nervous system.

What regulates contraction in cardiac muscle?

It is involuntary; the heart has its own pacemaker and is modulated by the nervous system.

Which control mechanisms affect smooth muscle contraction?

Involuntary control by the nervous system, hormones, and local chemicals.

Describe the cell shape and appearance of skeletal muscle fibers.

Single, very long, cylindrical, striated, and multinucleated.

What is the distinctive cellular arrangement of cardiac muscle fibers?

Branching chains of striated, uninucleated cells connected by intercalated discs.

How do smooth muscle cells differ in appearance from skeletal and cardiac muscle cells?

They are single, fusiform (spindle-shaped), non-striated, and uninucleated.

What is a fascicle in skeletal muscle?

A long bundle of skeletal muscle cells surrounded by connective tissue called the perimysium.

Name the connective tissue layer that surrounds individual skeletal muscle cells.

The endomysium.

Which intracellular structures house actin and myosin in skeletal muscle fibers?

Myofibrils.

What are sarcomeres?

The repeating, smallest functional units of striated muscle within myofibrils.

Summarize the Sliding Filament Theory of skeletal muscle contraction.

Muscle fibers contract when actin and myosin filaments slide past one another, shortening the sarcomere.

What is a neuromuscular junction (NMJ)?

A synapse between a motor neuron and a skeletal muscle fiber.

Define an action potential in the context of muscle physiology.

A rapid, transient change in membrane voltage that propagates along the cell membrane.

Why are intercalated discs important in cardiac muscle?

They electrically and mechanically couple cardiac cells, enabling synchronized heart contractions.