A cardiac muscle cell is: Question 31 options: a voluntary muscle just like skeletal muscle. contracts spontaneously. is joined to other cardiac muscle cells by structures called intercalated discs. has numerous nuclei. Two of the statements above are correct.

The correct answer is: Two of the statements above are correct.

A cardiac muscle cell contracts spontaneously and is joined to other cardiac muscle cells by structures called intercalated discs.

Explanation:

Cardiomyocytes, the only ones responsible for the contractile function of the myocardium, are terminally differentiated cells that cease to proliferate almost immediately after birth. Cardiomyocytes are mononucleated cells, with the nucleus in a central position. These are linked together by the so-called intercalary discs, which appear as dark bands in histological preparations, and which are a set of junction complexes where desmosomes and adherent junctions can be found (here called fascia adherens). The intercalary discs are therefore the boundaries between cells.

interphase

the period of cell growth when the cell synthesizes new molecules and organelles. the cell is not dividing and it constitutes the majority of the time spent in the cell cycle

prophase

changes occur in the nucleus and cytoplasm. the chromatin condenses to form structures (sister chromatids) visible with a light microscope and the mitotic spindle begins to form, but the nucleus is still in tact

prometaphase

the nuclear envelope fragments and the spindle microtubules attach to the kinetochores of the sister chromatids

metaphase

all the cell's duplicated chromosomes are lined up at an imaginary plane equidistant between the poles of the mitotic spindle

anaphase

begins when sister chromatids separate from each other and ending when a complete set of daughter chromosomes arrives at each of the two poles of the cell

telophase

the daughter nuclei form at the two poles of a cell

cytokinesis

the division of a cytoplasm to form two separate daughter cells. usually occurs during telophase during mitosis. this and mitosis make up to mitotic (m) phase of the cell cycle