<Li> The ER, which is part of the endomembrane system, which makes up a very large portion of the cell's total membrane content . The ER is an enclosed network of tubules and sacs, and its main functions include protein synthesis, and lipid metabolism . There are 2 types of ER, smooth and rough . The rough ER has ribosomes attached to it used for protein synthesis, while the smooth ER is used more for the processing of toxins and calcium regulation in the cell . </Li> <Li> The Golgi apparatus has two interconnected round Golgi cisternae . Compartments of the apparatus forms multiple tubular - reticular networks responsible for organization, stack connection and cargo transport that display a continuous grape - like stringed vesicles ranging from 50 - 60 nm . The apparatus consists of three main compartments, a flat disc - shaped cisterna with tubular - reticular networks and vesicles . </Li> <P> The cell membrane has different lipid and protein compositions in distinct types of cells and may have therefore specific names for certain cell types . </P> <Ul> <Li> Sarcolemma in myocytes: "Sarcolemma" is the name given to the cell membrane of myocytes (also known as muscle cells). Although the sarcolemma is similar to other cell membranes, it has other functions that set it apart . For instance, the sarcolemma transmits synaptic signals, helps generate action potentials, and is very involved in muscle contractions . Unlike other cell membranes, the sarcolemma makes up small channels called "t - tubules" that pass through the entirety of muscle cells . It has also been found that the average sarcolemma is 10 m thick as opposed to the 4 m thickness of a general cell membrane . </Li> <Li> Oolemma in oocytes: The oolemma of oocytes, or egg cells, are not consistent with a lipid bilayer as they lack a bilayer and do not consist of lipids . Rather, the structure has an inner layer, the fertilization envelope, and the exterior is made up of the vitelline layer, which is made up of glycoproteins; however, channels and proteins are still present for their functions in the membrane . </Li> <Li> Axolemma: The specialized plasma membrane on the axons of nerve cells that is responsible for the generation of the action potential . It consists of a granular, densely packed lipid bilayer that works closely with the cytoskeleton components spectrin and actin . These cytoskeleton components are able to bind to and interact with transmembrane proteins in the axolemma . </Li> </Ul>

Where is the cell membrane in plants found