“Interjections!” quotes from Schoolhouse Rock!

When Reginald was home with flu, uh-huh-huh,

The doctor knew just what to do-hoo.

He cured the infection

With one small injection

While Reginald uttered some interjections.

Hey! That smarts!

Ouch! That hurts!

Yow! That's not fair givin' a guy a shot down there!

Interjections (Hey!) show excitement (Yow!) or emotion (Ouch!).

They're generally set apart from a sentence by an exclamation point,

Or by a comma when the feeling's not as strong.

So when you're happy (Hurray!),

or sad (Awww!),

or frightened (EEK!),

or mad (Rats!),

or excited (Wow!),

or glad (HEY!),

an interjection starts the sentence right!