A stroke occurs when a blood vessel that carries oxygen and nutrients to the brain is either blocked by a clot or bursts. When that happens, part of the brain cannot get the oxygen it needs, and brain cells die.

About 795,000 Americans each year suffer a new or recurrent stroke. That means, on average, a stroke occurs every 40 seconds. Stroke kills more than 137,000 people a year. That's about 1 of every 18 deaths. It's the No. 4 cause of death.

HealthLink, Upstate's free lecture series, offers two talks on the subject of stroke, in which participants will be able to ask the expert during a question-and-answer period. They are:

• 6 to 7 p.m. Wednesday, May 8. "How To Prevent Stroke," with Waleed El Nour, MD from Upstate University Hospital. This will be held at the OASIS/HealthLink
Learning Center, 6333 St. Route 298, 
East Syracuse.

• 6 to 7 p.m. Wednesday, May 15. "TIA – What You Need to Know," with Adham Kamel, MD from Upstate University Hospital. This will be held at the Liverpool Library, 310 Tulip St., Liverpool. A transient ischemic attack is when blood flow to a part of the brain stops for a brief period of time.

Registration is required for these free presentations. Call 464-8668.

The Upstate Stroke Center is the region's first designated stroke center with the only specialized neuroscience step-down and neuroscience intensive care unit. And, the American Heart Association awarded the center with its 2013 Get With the Guidelines Gold Plus Award for Stroke Care.