Muscle cells, or muscle fibers, are unique in that they are multi-nucleated, containing several nuclei. They contract and relax to generate force and movement in the body. Muscle cells also have specialized structures called sarcomeres, which are responsible for muscle contraction.
A syncytium is a multi-nucleated cell formed by the fusion of individual cells. This results in a single continuous cytoplasmic mass. Syncytia are commonly found in certain tissues like muscle and placental syncytiotrophoblast.
i think that all three types of muscle have calmodulin , because every nucleated cell has it
Multi-nucleated cells can form through a process called cell fusion, where two or more individual cells merge to create a single cell with multiple nuclei. This often occurs in certain tissues, such as skeletal muscle, where myoblasts fuse during development to form muscle fibers. Additionally, some cells may undergo repeated mitosis without cytokinesis, resulting in multiple nuclei within a single cell. This phenomenon can also be observed in specific pathological conditions, such as viral infections, where the fusion of infected cells occurs.
Multi-unit Smooth Muscle.
If one were examine any type of muscle cell at the molecular level, what one would find is some kind of structured array of very thin (nano-scale) chains of protein called myofilaments.These are the smallest contractile elements in muscle tissue. There are two kinds of myofilaments: the thin actin filaments (~7 nm diameter), and the thicker myosin filaments (~16 nm diameter).In the case of skeletal and cardiac muscle these filaments alternate many times in parallel to the axis of muscle contraction.During muscle shortening, the job of myosin is to latch on to points along the actin filaments and pull them closer toward each other. During relaxation and muscle lengthening the gap between adjacent actin filaments increases.The muscle cells that are responsible for contracting sphinctors, blood vessels, bronchioli, the iris, and providing gut motility are a bit different. These are called smooth muscle cells. Instead of having a regular array of filaments parallel to axis of force-generation, they are arranged irregularly in a sort of criss-cross fashion that 'squishes' the cell as it contracts.
no they are not all nucleated
Skeletal muscles (the ones in arms, legs and other moving parts of the body) have large numbers of nuclei. They are formed during development by the fusion of many single nucleus myoblastcells . Other muscle cells, like the cardiac muscle cells in the heart or smooth cells in the gut, do not fuse and have only one nucleus. For more information see "Molecular Biology of the Cell" published by Garland Press.
RBCs in reptiles are nucleated.
yes
Bi-nucleated cells in ruminants, particularly in the context of their muscle tissue and certain placental structures, are characterized by having two nuclei within a single cell. These cells are believed to play a role in muscle growth and repair, as well as in the unique structure of the ruminant placenta, which helps facilitate nutrient exchange between the mother and the developing fetus. The presence of bi-nucleated cells can be attributed to specific developmental and physiological adaptations in ruminants, supporting their metabolic needs and reproductive strategies.
in order to correctly palpate a multi-joint muscle you must do what