Within skeletal muscle there are three types of fiber: Type I. Type I fibers are also known as slow twitch fibers. They are red in colour due to the presence of large volumes of myoglobin and so oxygen and high numbers of Mitochondria.or this reason the muscles containing mainly type I fibers are often postural muscles such as those in the neck and spine due to their endurance capabilities Also, athletes such as marathon runners have a high number of this type of fiber, partly through genetics, partly through training. Type IIa.
types of IUDs. 1  Hormonal There are four hormonal IUDs available in the U.S.âMirena, Skyla, Liletta, and Kyleena. 2  Non-Hormonal There's only one IUD without hormones available in the U.S. It's called ParaGard and it's made of plastic and a small amount of natural, safe copper.
Serious side effects of Mirena include severe cramps or pelvic pain, heavy or ongoing vaginal bleeding, unusual vaginal discharge, pale skin, easy bruising or bleeding, fever, chills, sudden numbness or weakness, severe headaches, or jaundice (yellowing of the skin or eyes).irena must be removed at the end of the 5-year wearing time. Your doctor can insert a new device at that time if you wish to continue using this form of contraception. Only your doctor should remove the Mirena intrauterine system.