I’m wondering whether it looks well-written and, most importantly, grammatically correct to use 2 synonyms at once in my following sentence:

Pacemaker Cells make up only about 1% of the Total Number of cardiac muscle cells and constitute the Cardiac Conduction system.

If it looks well-written and is grammatically correct when the audience read it, do you recommend me using a ‘comma’ after ‘muscle cells’ to prevent it from sounding too long for a sentence?

Pacemaker Cells make up only about 1% of the Total Number of cardiac muscle cells , and constitute the Cardiac Conduction system.

Original Quote:

‘Pacemaker cells make up only about 1% of the total number of cardiac muscle cells. There are three populations of these cells in the heart that are capable of spontaneously generating action potentials and setting the pace of the heart. These three cell populations are collectively called the cardiac conduction system. After looking at how pacemaker cells generate action potentials, we’ll cover the components of the cardiac conduction system’ (Amerman 2019).

Thank you!

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    To echo a point in the answer, capitalizing the extra words is very strange. Also, even though you are only paraphrasing the original author, you still need to provide a citation. Something like (without quotation marks) as Amerman says . . . (2019). Otherwise, it's plagiarism. Commented May 23, 2019 at 15:32

1 Answer 1


The first question that arises is why you have introduced a series of capital letters where the original quote used lower case letters. There is no obvious reason for any of the capital letters other than the P that introduces the first word of the sentence.

As to the need for a comma, if you think that a reader should pause for a moment after the words muscle cells in order to better grasp or convey the meaning of the sentence, then use a comma. However, the presence or absence of a comma will not affect the apparent length of the sentence, only the sense of it.

Your choice of make up and constitute is perfectly idiomatic. The words fit the intended sense exactly.

  • Thanks Ronald. I thought it would be fairly annoying to read my sentence, as I felt I was basically writing "make up" 2 times. For e.g., "makes up __ and makes up ___". I'm concerned about putting a comma before "and". Would it be still grammatically correct? I've read about "parallelism", "the use of comma", and "conjunctions" for English grammar, but they can't address the issue. Usually a comma is added when there is a set of 3 verbs/nouns/adjectives. Commented May 23, 2019 at 12:51
  • For e.g.: There are three houses, two cars, and twenty people; It is red, blue, and purple; he can dance, run, and swim. Commented May 23, 2019 at 12:52
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    When the use of a comma assists a reader to better grasp the meaning of a sentence, use a comma. In your case, I believe it does. For example: I spoke to John and Peter, and Susan listened in. The presence of a comma after Peter makes it much easier to grasp the meaning. Commented May 23, 2019 at 13:13
  • Thanks Ronald. You're awesome! Commented May 25, 2019 at 2:52

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