: operator when used in plot function

I would just like to know what the : operator does when used to plot in the following context:

plot(x,Tanal(:,Nt),

I can see that x is plot against Tanal for some values of Nt but cannot quite work out which is refers to.

Thanks

Answer 1

[the cyclist]

All rows of the Nt 'th column of Tanal.

[Mike Scott]

Ah OK, I see now. So by removing the : operating it plots all rows of data within the Tanal matrix. Thanks for your help