But the arrival of the dockless bike-share model was received mostly with praise and excitement in a city that has embraced biking as a mode of transportation. Some biking aficionados said they hope the companies will indeed bring more bikes to underserved communities of the District, including the Northeast and Southeast quadrants.
It sounds super-gross but please try to imagine it: Red muscles, pink muscles, and white muscles. The red muscles are red because they contain lots of myoglobin: a protein that binds iron and oxygen. Your blood has a similar protein called hemoglobin which binds iron and oxygen.
This is why skeletal muscle is called STRIATED MUSCLE (i.e., the alternating light and dark areas look like stripes or striations). The light areas are called the I-BANDS and the darker areas the A-BANDS. Near the center of each I-BAND is a thin dark line called the Z-LINE (or Z-membrane in the drawing below).