The hormone calcitonin, which is produced by the parafollicular or C cells of the thyroid, has the opposite effect on blood calcium levels as does PTH. I hope this helps! : )
Answer: the cells differentiate
Because there is no indication of what's the highlighted structure I'm going to tell you where all the four muscles of the quadriceps femoris originate from.
The vastus lateralis originates on the greater trochanter and the lateral lip of linea aspera. The vastus intermedius originates on the lateral and anterior surfaces of the femur's body. The vastus medialis originates on the medial lip of the linea aspera and the intertrochanteric line. R<span>ectus femoris originates, </span>superior to the acetabulum, on <span>the ilium.</span>