Instructors are the authors and copyright owners of their course materials (this includes things like lecture notes, PowerPoint presentations and exams). The written version of a lecture as well as the verbal delivery (i.e. performance) of that lecture are both protected by copyright. Since a copyright owner has the right to control what can be done with their works, you may not record an entire lecture (or copy entire lecture notes or exams) without the prior permission of your instructor.
There are, however, certain users' rights included in the Copyright Act which allow the copying of a copyright protected work, in specific situations. Under fair dealing, you may copy a short excerpt of a copyright protected work for purposes including private study, education and research.
Contact the Copyright Office (firstname.lastname@example.org) with any questions.
Please note that if you require your course materials in a different format due to a disability you can contact the Centre for Students with Disabilities for assistance with such accommodation.