Multiple sclerosis (ms) is a disease that affects the nerve cells of the brain and the spinal cord. some of the symptoms of ms are chronic pain, pins-and-needles sensations, muscle weakness, and visual disturbances. study the image, and then explain the cause for these symptoms.

Ans.

Multiple sclerosis is an autoimmune disorder of nerve cells of spinal cord and brain. It is caused due to destructive immune response of body against covering of nerve cells . The axons of nerve cells are covered by a myelin-sheath, which provides insulation to the nerve cells and speeds up the rate of nerve transmission.

In healthy nerves, axons are insulated properly with myelin sheath and these nerve cells will perform perform proper function. In nerves affected with multiple sclerosis, nerve axons are demyelinated as the myelin sheath is damaged. It leads to impairment in signal transduction and results muscle pain, needles sensation, and deficiency in cognition, movement, or sensation.

interphase

the period of cell growth when the cell synthesizes new molecules and organelles. the cell is not dividing and it constitutes the majority of the time spent in the cell cycle

prophase

changes occur in the nucleus and cytoplasm. the chromatin condenses to form structures (sister chromatids) visible with a light microscope and the mitotic spindle begins to form, but the nucleus is still in tact

prometaphase

the nuclear envelope fragments and the spindle microtubules attach to the kinetochores of the sister chromatids

metaphase

all the cell's duplicated chromosomes are lined up at an imaginary plane equidistant between the poles of the mitotic spindle

anaphase

begins when sister chromatids separate from each other and ending when a complete set of daughter chromosomes arrives at each of the two poles of the cell

telophase

the daughter nuclei form at the two poles of a cell

cytokinesis

the division of a cytoplasm to form two separate daughter cells. usually occurs during telophase during mitosis. this and mitosis make up to mitotic (m) phase of the cell cycle