Answer:
The intense and constant activity of insulin synthesis explains why pancreatic beta cells possess more rough endoplasmic reticulum and ribosomes than other cells.
Explanation:
Both ribosomes and the rough endoplasmic reticulum are necessary for protein synthesis to occur. In cells whose function is to produce substances, such as glands, the content of these cellular structures is higher in order to fulfill their function.
The pancreatic beta cells, located in the islets of Langerhans, have the function of synthesizing insulin, an endocrine hormone in charge of regulating the glucose content in the blood. <u>Because the beta cells constantly produce insulin, their content of rugged endoplasmic reticulum and ribosomes is high, in order to satisfy the demand for this hormone in the body</u>.
Its found in the tectum of the dorsal aspect of the midbrain
Microfilaments
Microfilaments are fine, thread-like protein fibers, 3-6 nm in diameter. They are composed predominantly of a contractile protein called actin, which is the most abundant cellular protein. Microfilaments' association with the protein myosin is responsible for muscle contraction. Microfilaments can also carry out cellular movements including gliding, contraction, and cytokinesis.
Microtubules
Microtubules are cylindrical tubes, 20-25 nm in diameter. They are composed of subunits of the protein tubulin--these subunits are termed alpha and beta. Microtubules act as a scaffold to determine cell shape, and provide a set of "tracks" for cell organelles and vesicles to move on. Microtubules also form the spindle fibers for separating chromosomes during mitosis. When arranged in geometric patterns inside flagella and cilia, they are used for locomotion.
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The development of the human embryo follows fertilization, and continues as fetal development. By the end of the tenth week of gestational age the embryo has acquired its basic form and is referred to as a fetus. The next period is that of fetal development where many organs become fully developed.
