As California prepares for expanded use of marijuana, UC Davis is offering courses in the science of the drug to boost awareness of its affect on the body.

The courses, called “Physiology of Cannabis,” are believed to be the first of their type in the University of California system. They join a small but growing number of weed-focused studies around the nation, reflecting the country’s changing attitude toward the drug.

“We feel it is important at this moment to educate students about the physiology and medical indications of cannabis and cannabinoids,” said instructor Yu-Fung Lin, an associate professor of physiology and membrane biology at the UC Davis School of Medicine.

UC Davis already has a longstanding Weed Research & Information Center. But that focuses on plants other than cannabis, such as crabgrass, clover and dandelions.

The new undergraduate-level course, launched in early April, can be used by undergraduates to fulfill the “Science and Engineering” general educational requirement to graduate. A more advanced class will be offered next year to medical students at the UC Davis School of Medicine.

A course for the general public also is planned in the future, allowing civic leaders, law enforcement and other people to learn more about the drug.

Education has been hampered by a lack of access to good information, as well as high-quality research.

Passage of Proposition 64 last November means it’s now legal to possess recreational marijuana in California. Possession of medical marijuana has been legal since 1996. But the state has until January 1, 2018, to figure out how to license commercial businesses — so it can’t be bought or sold until then.

After that, experts expect it may be tried by many Californians who steered clear during its prohibition. But be warned: It remains classified by the federal government as an illegal Schedule I drug, defined as having a potential for abuse and addiction and no medical value, so there is still risk of arrest.

Twenty-eight states and the District of Columbia have legalized marijuana for a variety of medical uses. Recreational use for people over the age of 21 is allowed in eight of those states, as well as the District. The percentage of American adults living in states where marijuana use is legal for adults is above 20 percent; before Election Day, it was 5 percent.

The course will cover the chemicals found in the plant; the medical chemistry of THC and cannabinoids, the active ingredients in the drug; the body’s own endocannabinoid system, with two types of receptors, CB1 and CB2, that bind to different components in marijuana; emerging therapeutic applications and the health risks of the drug.

“Cannabis is not my research background,” said Lin, who studies the molecular level-functioning of “ion channels,” proteins in the cell that convert chemical or mechanical messages into electrical signals, transmitting signals in the nervous system, for instance.

Oakland’s Oaksterdam University, the nation’s only cannabis-specific campus, has long offered courses.

The medical school at the University of Vermont offers a course, as does Harvard Law School, Vanderbilt University School of Law in Nashville, and Ohio State’s Moritz College of Law. The Massachusetts Medical Society offers an online courses, including one on pharmacology.

Lin and Luis Fernando Santana, professor and chair of physiology and membrane biology at the UC Davis School of Medicine, hope the UC Davis courses will be a blueprint for additional cannabis studies.

“The timing could not be better to give students the opportunity to have a profound understanding about the physiology and medical implications of cannabis use,” said Santana, in a prepared statement.