Resistance and impedance more-or-less describe the same phenomenon.
The subtle difference is that resistance is typically a DC (direct current) measurement, whereas impedance is an AC (alternating current) measurement.
For instance, if you measure a loop of wire with a DC ohm meter, you will get 0 Ohms, which is the DC resistance. However, if you then put an AC signal across the loop and measure it's impedance (you can do this with an oscilloscope in XY mode where 1 axis is the voltage and the other axis is current, and computing impedance from the slope of the line since R=V/I), you will observe that the impedance will start out at or near 0 for low frequencies, but then increase as you increase the frequency (incidentally, this is due to the inductance of the wire).