Kris Jenner's mother, Mary Jo's, cause of death has been revealed days after her passing.Mary Jo "MJ" Shannon passed away on July 16 at the age of 91. Kris Jenner shared the news in a heartfelt Instagram post. However, at the time, the cause of the Shannon's death was not revealed. On July 28, Us Weekly obtained Mary Jo's death certificate, which attributed her death to "acute cardiopulmonary arrest.As per the death certificate, other medical conditions like metastatic lung cancer and acute respiratory failure also contributed to Kris Jenner's mother's death. Per Us Weekly, no autopsy was performed after the death of the 91-year-old. The Kardashian sisters' grandmother was cremated on July 23.On July 16, Kris Jenner penned a lengthy post on Instagram, remembering her mother."Today, we said goodbye to my beautiful Mommy MJ. There are no words that could ever capture what she has meant to me or the heartbreak of having to say goodbye. My mom was the heart of our family. She taught me everything that truly matters," she wrote.Kris Jenner further remembered the teachings of her mother and thanked her for "every sacrifice" she made."Our hearts are broken, but we find comfort knowing that love like yours never truly leaves us. Your love will live on in our family, in our traditions, in every moment we are together, and in every life you touched. When I look at my kids and my grandkids, I will forever see pieces of you in all of us. There is not a part of me that isn’t shaped by you... My heart is broken into a million pieces… I love you forever Mommy. Thank you for giving us everything," she wrote.In addition to their mother, the Kardashian sisters also paid tribute to their grandmother via social media posts.Kris Jenner and Kim Kardashian recently shared posthumous birthday tributes to Mary Jo View this post on Instagram Instagram PostMary Jo passed away just days before her 92nd birthday. On Sunday, Kris Jenner took to Instagram and shared a series of her mother's pictures. Along with photos, the Kardashian matriarch captioned the post with:"Happy Heavenly Birthday Mommy. I love you."Kim Kardashian, who was close to her late grandmother, also remembered Mary Jo in a posthumous celebratory post. The SKIMS founder also shared a number of throwback pictures and wrote:"Happy Heavenly 92nd Birthday grandma! It’s only been a week but wow the amount of things I’ve learned about you this week from going through all of your stuff with mom has been beautiful ! I thought I knew it all! Makes me respect you and love you more if that’s even possible. Today we celebrate you! I miss you like crazy and I love you endlessly my sweet grandma MJ."Mary Jo appeared multiple times on Keeping Up with the Kardashians over the years.Also read: Kim Kardashian addresses backlash over Instagram vacation photos coincided with grandmother’s death announcement