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Born in the small rural ski resort town of Show Low, Arizona, Cristal Sumerlin is a dedicated Physician Assistant specializing in Internal Medicine. With a strong passion for patient care and a desire to play an active role in their treatment and well-being, she chose the professional career path of a Physician Assistant after working as an X-Ray Technician. Cristal fell in love with medicine and recognized the need to further her education to better serve her patients and the community.

Cristal takes great pride in both her personal and professional accomplishments. As a mother and military spouse, she has successfully balanced the demands of family life while pursuing her professional goals. Her commitment to her patients and dedication to her work make her a source of pride and inspiration.

In the field of Internal Medicine, Cristal's strengths lie in managing complex disease processes such as diabetes. Her previous experience as an orthopedic technician and x-ray tech in an orthopedic practice has also honed her skills in orthopedics. She finds fulfillment in working with patients facing orthopedic conditions and providing comprehensive care.

Beyond her career, Cristal enjoys spending time outdoors and engaging in activities such as camping, hiking, and traveling. She cherishes these moments with her friends and family, as they provide a source of rejuvenation and happiness outside of her job.

With her unwavering dedication, clinical expertise, and compassionate approach, Cristal Sumerlin is an invaluable asset to Dr. Richard Lam's office. She strives to make a positive impact on her patients' lives and is committed to providing comprehensive and personalized care to improve their overall well-being.

Dr. Kathy Zelken is returning as an aesthetic medicine provider after a hiatus since the birth of her daughters. She has served as the medical advisor of the Zelken Institute for Aesthetic Medicine since it was established in 2016. She has worked tirelessly in the background to ensure the highest level of excellence and quality in all aspects of patient care. She has had a keen eye for artistry since childhood, starting from being a classically trained artist. She graduated summa cum laude from the University of California Berkeley with a major in Molecular and Cell Biology and a minor in Art History. During medical school at the University of Texas Southwestern, she published papers with world-renowned plastic surgeon and former editor-in-chief of Plastic and Reconstructive Surgery journal (the top journal in the field), Dr. Rod Rohrich. Her meticulous nature, extraordinary calmness, and friendly demeanor gained from close to a decade of working as a board-certified pediatrician in Orange County and doing some of the most delicate procedures on tiny babies will put the most anxious patients at ease. She is thrilled to help patients map out a comprehensive treatment plan to achieve their individual aesthetic goals and explain various nonsurgical procedures in detail. Her patients love her and seek her out for neuromodulator and facial contouring injections, skin rejuvenation, laser treatments, and so much more.

Ella graduated in June 2025 from the University of California, Irvine with a Bachelor of Arts in Psychological Sciences. With an interest in both therapy and administrative work, she was drawn to Mind Health Institute, Orange County. Ella is excited to make connections with patients and give them the best possible experiences at Mind Health Institute, Orange County.

Dr. Kenna Schnarr is dual-boarded in Obstetrics and Gynecology and Family Medicine, bringing a comprehensive, patient-centered approach to women’s health. Originally from a small town with very few doctors, Dr. Schnarr values strong patient relationships and continuity of care. With training across both primary care and women’s health, Dr. Schnarr is committed to delivering comprehensive, holistic care to women at every stage of life — what she describes as “womb to tomb.”

She earned her medical degree with clinical honors from Kansas City University of Medicine and Biosciences, where she also completed a fellowship teaching anatomy and pathology to medical students alongside continuing breast cancer research. Prior to medical school, she earned a Master’s in stem cell and cancer biology, with research focused on using stem cells to treat triple negative breast cancer. Dr. Schnarr has authored multiple peer-reviewed publications and is passionate about mentoring, medical education, and interdisciplinary collaboration. Outside of medicine, she enjoys fitness, culinary exploration, international travel, and spending time with her spouse, family, and friends.

Dr. Brittany Glenn, D.O., is a board-certified emergency medicine physician bringing over ten years of experience caring for patients in emergency rooms to Cali Quick Urgent Care, serving people of all ages in Laguna Niguel, California, and southern Orange County.

Dr. Glenn grew up in Shaker Heights, Ohio and began her collegiate pursuits at Miami University in Oxford, Ohio, earning her Bachelor of Arts in psychology. She subsequently obtained a Master of Arts in bioethics at Case Western Reserve University in Cleveland, Ohio. After receiving her master’s degree, Dr. Glenn earned her medical degree at Ohio University in Athens, Ohio.

Dr. Glenn completed an extensive four-year emergency medicine residency at the University of Pittsburgh Medical Center (UPMC) Hamot in Erie, Pennsylvania. Dr. Glenn has since served at various medical facilities and hospitals in Cleveland, Ohio and southern California. She’s board-certified in emergency medicine from the American Osteopathic Board of Emergency Medicine (ABOEM). She holds basic life support (BLS) and advanced cardiovascular life support (ACLS) certification from the American Heart Association.

Outside the office, Dr. Glenn enjoys spending time with her family. She co-founded and operates the urgent care and CQ Med Gym with her husband and is a mother of three young children under the age of 11. Her children were the inspiration for Cali Kids Urgent Care. Dr. Glenn welcomes anyone needing urgent or acute care to Cali Quick Care & Cali Kids Urgent Care to be treated like family, friends, and neighbors.

Excellence is at the heart of the care that Marcella Bonnici, MD provides for each of her patients at her aesthetics and family medicine practice serving Wildomar, Murrieta, Temecula, CA, and the surrounding areas. 

From her days as an undergraduate student to the moment she chose to return to her California roots, Dr. Bonnici has demonstrated a commitment to learning more about preventive care and family medicine, using that knowledge to improve her patient’s quality of life.   

After earning her Bachelor of Science in biological sciences at the University of California, Irvine, Dr. Bonnici completed her medical studies at the historic Ross University School of Medicine. She later trained at several hospitals throughout the boroughs of New York City. She went on to receive the Outstanding Second Year Resident Award and was nominated for the Arizona Academy of Family Physicians Brazie Award while she was a resident at Scottsdale Healthcare.  

Dr. Bonnici’s love of family medicine and her interest in preventive care inspired her to open her first practice in Scottsdale, Arizona. Motivated by her love of her native California, she returned to her home state to help her fellow Californians lead healthy lives.    

Daniel Headrick, MD, is the medical director and owner of Tres Vistas Recovery in San Juan Capistrano, California. Before opening Tres Vistas Recovery, Dr. Headrick served for eight years as the medical director at Mission Hospital in Laguna Beach, California, and eleven years as the Medical Director of Hoag Hospital’s Chemical Dependency Center in Newport Beach, California.

Dr. Headrick — known by his patients as Dr. Dan — received his medical degree from the University of California, Los Angeles Medical School. He received his postgraduate certification from the American Society of Addiction Medicine in 1988 and became an associate professor at the University of California, Irvine Medical School. Dr. Dan continues his training and research in chemical dependency to stay abreast of current techniques and apply them in his work.

Dr. Dan dedicates much of his time to the care and treatment of his clients, overseesoverseeing their stabilization to make sure that they have a sound transition into treatment and recovery. He cares for each of his clients individually as they go through withdrawal from alcohol and other substances. To schedule an appointment with Dr. Dan and his team, call Tres Vistas Recovery or book online today.