a-short-review-of-histology

Muscle, Tendon, Bone connections:

In skeletal (and smooth) muscle the contractile elements within the cytoplasm interact to cause a shortening of the fibre
The contractile elements within the cytoplasm anchor to the inside of the cell membrane of the ends of the fibre
The collagen fibres of the supporting connective tissue anchor into the basement membrane of the ends of the muscle fibre
The ends of the muscle fibre are irregular to provide a greater surface area for the insertion of the collagen fibres into the basement membrane
At the ends of each skeletal muscle, the endomysium, perimysium and epimysium converge to become continuous with the dense regular connective tissue of the tendon
During early development, the presumptive connective tissue of the tendon is associated with the connective tissue which is destined to differentiate into cartilage/bone
The deposition of cartilage/bone matrix around the collagen fibres of the presumptive tendon created an anchorage for the tendon
As bones grow and increase in size, more and more of the tendon becomes incorporated into the bone matrix
This provides an increasingly firm anchorage as the individual increase in size and the tension on the attachment site increases
The tendinous collagen fibres that are incorporated into bone matrix are known as Sharpey's fibres

Micrograph of Dense Connective Tissue:

This micrograph shows dense connective tissue (stained red) of the tendinous insertion of skeletal muscle cells of the tongue
Note that the connective tissue (red) appears to envelope the ends of the skeletal muscle cells (orange)
In the tongue, skeletal muscle cells are attached laterally to bone but in the midline to a band of connective tissue known as a raphe
A similar arrangement is found in the anterior abdominal wall
However the association between the skeletal muscle cells and the midline raphe is similar to that found where muscle cells link to a tendon