ports 0 - 1023 are well known ports which has specific services running like ftp which runs on port 21, port 23 for telnet etc..

ports 1024 - 49151 are registered ports (the ports you mentioned comes in this) these ports are used by browsers, ftp softwares who open random ports within these to communicate. So there is nothing for you to worry.

ports 49152 -65535 are private ports which are used by trojans.. if you find any of these ports open,you need to do something.

TCP (transmission control protocol) It is the reliable transport protocol in the tcp/ip suite. Reliable means it recovers from lost data

UDP (user datagram protocol) It is unreliable protocol as it does not maintain any provision for recovery of data loss in transmission. But its faster and mainly used in video transmissions where some data loss doesnt do any harm

ICMP- Internet cntrol message protocol - It is used to replay network conditions, different errors to ip and other layers.

Hope that clears all your doubts.