Regarding gmail account on android

I'm an user of htc one m8. I have a doubt regarding my gmail account. My account is always signed in when i open gmail app on my mobile. Is there any change of signing out from the account? I heard that we can do it by removing the account.. if i remove my gmail account then i'm out of gmail only or entire google accounts? and also if i remove my gmail account can i have access to google play store or removing gmail keeps me out of google play store too..the think is i dn't want my friends to access my mails when they use my phone. Hope you answer my query..the thing is i just want to logout from gmail and not entire google accounts. Is it possible?

Thankyou.

What about using an app like to lock specific apps, requiring a PIN to open them?
https://play.google.com/store/search?q=app%20locker

Thank you for the reply.
What if i remove my gmail account? Does that keep me away from all google accounts like google play store, drive etc..?

If that email is your main Gmail account then by removing it you will not have access to Google Play Store and none of the Google services.

Posted via Android Central App

Thank you. Your reply has cleared my doubt :)