Dec 17, 2020 — The human digestive system is comprised of specialized cells, tissues, and organs. Which lists the ... a. muscle tissue, muscle cell, stomach. ... (or small bowel) is a 20-25 foot long, specialized tube (between the stomach and ... The lining also contains specialized groups of cells that produce chemicals .... Each type of cells is specialised to carry out a particular function, either solely, but ... food is propelled through the digestive system via wavelike contrac