where are the microtubules located in an animal cell
Microtubule organizing center Most animal cells have one MTOC during interphase, usually located near the nucleus, and generally associated closely with the Golgi apparatus. The MTOC is made up of a pair of centrioles at its center, and is surrounded by pericentriolar material (PCM) that is important for microtubule nucleation. Microtubules are anchored at the MTOC by their minus ends, while their plus ends continue to grow into the cell periphery. The polarity of the microtubules is important for cellular transport, as the motor proteins kinesin and dynein typically move preferentially in the "plus" and "minus" directions respectively, along a microtubule, allowing vesicles to be directed to or from the endoplasmic reticulum and Golgi apparatus. Particularly for the Golgi apparatus, structures associated with the apparatus travel towards the minus end of a microtubule and aid in the overall structure and site of the Golgi in the cell.[3]
Sarcolemma A special feature of the sarcolemma is that it invaginates into the cytoplasm of the muscle cell, forming membranous tubules radially and longitudinally within the fiber called transverse tubules (T-tubules). On either side of the transverse tubules are Terminal cisterna enlargements of smooth endoplasmic reticulum termed sarcoplasmatic reticulum (SR) in muscle. A transverse tubule surrounded by two SR cisterna are known as triads, and the contact between these structures is located at the junction of the A and I bands.