Cardiac Muscle Quiz

What type of muscle fibers compose the main bulk of the wall of the heart?

• Striated muscle fibers

• Cardiac muscle fibers

• Skeletal muscle fibers

• Smooth muscle fibers

How many nuclei do cardiac muscle cells typically possess?

• One or two

• Five or six

• None

• Three or four

What is the primary function of intercalated discs?

• To generate electrical impulses

• To provide structural support

• To form junctional complexes

• To store calcium

Which of the following is NOT a specialization found within intercalated discs?

• Gap junctions

• Desmosomes

• Tight junctions

• Zonula adherens

What is the role of desmosomes in cardiac muscle?

• To store glycogen

• To facilitate electrical conduction

• To bind cardiac cells together

• To anchor actin filaments

What are Purkinje fibers?

• Modified skeletal muscle cells

• Modified cardiac muscle cells

• Nerve fibers

• Smooth muscle fibers

What is the primary characteristic of cardiac muscle fibers compared to skeletal muscle fibers?

• They are branched

• They are non-striated

• They are voluntary

• They have multiple nuclei

What is the appearance of cardiac muscle fibers under a microscope?

• Smooth and non-striated

• Striated and branched

• Flat and elongated

• Round and smooth

Which component is most prominent in the transverse portions of the intercalated disc?

• Gap junctions

• Mitochondria

• Desmosomes

• Zonula adherens

What fills most of the cytoplasm in Purkinje fibers?

• Lipid

• Glycogen

• Protein

• Calcium