Muscle cell Same same but different Muscle cell Other organismal cells sarcoplasm cytoplasm sarcoplasmic reticulum smooth endoplasmic reticulum (SER) sarcosome mitochondrion sarcolemma cell membrane New terminology So these new words are nothing new to you, they only have different words The reason is it is a specialized cell with special functions Most importantly it needs to be able to contract Three different muscles Striated muscle cell Cardiac muscle cell Smooth muscle cell Smooth muscle Smooth muscle is not under voluntary control It is not as highly organized as the other types You'll find this in arteries, guts, urinebladder, Uterus, respiratory tract and reproductive tract Examples of smooth muscle cells Striated muscle cell Features a repeated unit called sarcomere Is highly organized Control is voluntary (except for heart cells) All (except heart) is somehow attached to skeleton Have several nucleus and not placed in the centre Myofibrils are consisting of repeating segments of sarcomeres – long fibrous proteins Build up of Striated muscle Sarcomere This is how it looks under microscope Cardiac cells Striated muscle Not voluntary control Central nuclei as opposed to striated cells Usually only one nucleus (up to 4) High mitochondrial density (why???)