Have you had a recent hospital stay or emergency room visit? Please be sure to contact our office to keep us updated, and to schedule a follow up if necessary.

Providers and Staff
Keith Ryan, MD
Dr. Keith Ryan is board certified by the American Board of Internal Medicine. He graduated with a Bachelor's of Science in Zoology and a Minor in Music Performance from the University of Northern Arizona. He received an MD from the University of Missouri-Columbia and did his internship and residency at the University of Utah Hospital and Clinic in Salt Lake City, Utah. He enjoys spending time with his family, traveling, participating in outdoor activities, and playing music in his band F-Town Sound.
Sherrill Weller, DO
Dr. Sherrill Weller is board certified by the American Board of Internal Medicine. She graduated from the University of San Diego with a Bachelor of Arts in Biology and a Minor in Chemistry. She received her Doctor of Osteopathic Medicine from Western University of Health Sciences in 1997. Dr. Weller was a recipient of the Health Professions Scholarship Program, and upon completion of medical school was commissioned a Lieutenant in the United States Navy. Dr. Weller completed her internship and residency at Naval Medical Center San Diego in Internal Medicine. As a staff internist with the US Navy, she served at Naval Hospital Pensacola, Naval Medical Center San Diego, and on several operational platforms including the hospital ship USNS Mercy. Dr. Weller continued to work for the Navy after completing her service obligation working at Naval Hospital Jacksonville and at the Branch Health Clinic in Coronado, CA while her husband continued his career in Naval Aviation.Dr. Weller received several medical teaching awards, the Navy Marine Corps Commendation Medal (2) and earned the distinction of Fellowship in the American College of Physicians.Sherrill enjoys spending time with family, skiing, traveling and the outdoors. Sherrill and her husband are excited to return to the community of Flagstaff.
Katherine Costa, NP

My name is Katherine Costa, and I have been a nurse practitioner for 20 years. I am happy to be back at Ryan Internal Medicine. When I'm not seeing patients, I am teaching nursing at Coconino Community College. I also enjoy hiking with my husband and dogs and caring for my chickens.
Jessica Holst, FNP
Jessica is a Family Nurse Practitioner who was born and raised in Prescott, AZ and has lived in Flagstaff for the last 13 years. She graduated from Arizona State University with a Bachelor of Science in Exercise Science. She received her nursing degree from Yavapai College and she completed her graduate degree as a Family Nurse Practitioner at Northern Arizona University. When she is not working shes loves doing anything outside with her two dogs, traveling with her husband, relaxing with her cat and fostering animals through Tuba City Humane. 
Stacie
Hi, my name is Stacie, and I'm the office manager here at Ryan Internal Medicine. I grew up in Tuba City and graduated from Tuba City High School. I attended Northern Arizona University. I have been in the medical field for over 20 years. I have four beautiful children and between them and work, that is my life! I have worked at Ryan Internal Medicine for almost fourteen years and really enjoy what I do. Our patients are the best!
Krystalynn
Hello, my name is Krystalynn. I have been a medical assistant since 2004 when I completed the medical assistant program at The Bryman School in Phoenix, Arizona. My husband and I have four beautiful children. I enjoy being with my family, great music, art, and the occasional walk/hike. I look forward to meeting you.