I'm not sure if this is correct, but the answer I got was: endoplasmic reticulum.
I hope this helps, and have a good night! :D
Answer:Smooth muscle or “involuntary muscle” consists of spindle shaped muscle cells found within the walls of organs and structures such as the esophagus, stomach, intestines, bronchi, uterus, ureters, bladder, and blood vessels.
Explanation:
Smooth muscle or “involuntary muscle” consists of spindle shaped muscle cells found within the walls of organs and structures such as the esophagus, stomach, intestines, bronchi, uterus, ureters, bladder, and blood vessels.