Hjernen er en del af kroppen.

Because -en is the definite singular ending for many Danish nouns of common gender.

• en hjerne = a brain
• hjernen = the brain

So hjernen means the brain, not just brain in a general dictionary form.

For the same reason: kroppen is the definite singular form.

• en krop = a body
• kroppen = the body

In this sentence, Danish uses the body, so you need kroppen.

That is one of the basic features of Danish grammar. In many cases, Danish marks definiteness with a suffix attached to the noun.

Examples:

• en bil = a car
• bilen = the car
• et hus = a house
• huset = the house

So instead of a separate word like English the, Danish often adds -en, -et, -ene, or -ne to the noun.

Because del is a countable noun, and here it means a part.

• en del = a part
• delen = the part

In the expression en del af ..., Danish means a part of ....
So:

• en del af kroppen = a part of the body

You normally cannot leave out en here.

Af means of in this sentence.

So:

• en del af kroppen = a part of the body

It is a very common preposition in Danish.

This is the normal word order for a simple statement:

• subject + verb + complement

So here:

• Hjernen = subject
• er = verb
• en del af kroppen = complement

This is similar to English:

• The brain is a part of the body.

Er means is / am / are. It is the present tense of at være = to be.

Examples:

• Jeg er træt. = I am tired.
• Du er her. = You are here.
• Hjernen er en del af kroppen. = The brain is a part of the body.

Unlike English, Danish does not change the present-tense form depending on the subject. It stays er.

All three are common gender nouns, so they take en in the singular indefinite form:

• en hjerne
• en del
• en krop

That is why their definite singular forms are:

• hjernen
• delen
• kroppen

This is a spelling pattern in Danish. When some nouns add the definite ending, the final consonant is doubled in writing.

• en krop → kroppen
• en kat → katten

This helps show that the vowel before the consonant is short.

So kroppen is the correct spelling, not kropen.

No, that would sound wrong in standard Danish.

You need en del, because del is a singular countable noun here. Danish, like English, usually needs an article in this kind of phrase.

Correct:

• Hjernen er en del af kroppen.

Not standard here:

• Hjernen er del af kroppen.

The h is basically silent here, so hj starts with a y-like sound.

A rough English approximation is:

• hjernen ≈ YAIR-nen or YER-nen

But the real Danish pronunciation is softer and more central than English sounds. The important thing for a learner is:

• do not pronounce the h strongly
• the word begins roughly with a y sound

No. In modern Danish, nouns are not normally capitalized.

So you write:

• Hjernen er en del af kroppen.

Only the first word of the sentence is capitalized here because it begins the sentence, not because it is a noun.

Yes. Even though the Danish sentence contains en del = a part, natural English may be either:

• The brain is a part of the body
• The brain is part of the body

Both are fine translations, even though the Danish structure explicitly includes en.

It is most naturally understood as a general statement about anatomy.

Danish often uses the definite form in general statements of this kind:

• Hjernen = the brain in a general sense
• kroppen = the body in a general sense

So it is not necessarily about one particular person’s brain and body. It can mean the brain as an anatomical organ in general.

The dictionary forms are the indefinite singular forms:

• hjerne = brain
• del = part
• krop = body

You would usually learn them with their article:

• en hjerne
• en del
• en krop

That helps you remember the gender.