Transverse tubules. - tubules formed by invaginations of the sarcolemma and flanked by the sarcoplasmic reticulum, they carry action potentials deep into the muscle fiber. T tubules and SR provide tightly linked signals for muscle contraction. T tubules at each A band/I band junction-continuous with the sarcolemma.
Standard Sizes of Sofas. Sofas vary in size, from 6 to 8 feet long and 32 to 40 inches deep for a standard size sofa, to 4 to 6 feet long and 28 to 30 inches deep for a loveseat.The actual depth of the seating area is reduced by the depth of the sofa's arms and back of the sofa.ofas vary in size, from 6 to 8 feet long and 32 to 40 inches deep for a standard size sofa, to 4 to 6 feet long and 28 to 30 inches deep for a loveseat.
The Back Cushion. Another measurement that usually matters to people shopping for sofas is the thickness of the back cushion. The standard thickness of back cushions, whether itâs a loveseat or a three-seat sofa chair, is about 8 inches. That speaks comfort for most people.