Dizziness is not actually caused by the visual disturbance which we see when spinning around, but is caused by the ear. The ear has three loops which are filled with liquid. these are known as the semi-circular canals'. Each canal has tiny hairs growing in it. These hairs are all connected to nerves which carry messages to the brain.
When you move the liquid gently 'swishes' back and forth against the hairs, which makes them bnd. The brain then corrects the balance in the body, through contracting and releasing muscles.
However, when a person spins round, the liquid is jolted rapidly over the hairs and the brain gets confusing information. Consequently it cannot automatically correct the balance and the dizziness is a result of the brain's inability to regain balance. It is also a sub-conscious means of the brain telling the body that the spinning has to stop !