In adult amphioxus (Figure 1), muscle segments (myomeres) extend along the length of the body axis. Although amphioxus lacks skeletal tissue, collagen-based connective tissues with few or no cells are found in the positions where the vertebrate axial skeleton forms.

Do amphioxus have myomeres?

In adult amphioxus (Figure 1), muscle segments (myomeres) extend along the length of the body axis. Although amphioxus lacks skeletal tissue, collagen-based connective tissues with few or no cells are found in the positions where the vertebrate axial skeleton forms.

What are myomeres and Myosepta?

bundles of muscle fibres called myomeres. The myomeres are separated by thin horizontal (myosepta) and vertical (myocommata) layers of connective tissue. The unique structure and thin connective tissue sheaths of fish muscle give the meat its characteristic soft, flaky texture.

What is the function of the myomeres in the amphioxus?

They are involved in the specialized notochord of amphioxus. There are muscle cells within myomeres that send, and synapse cytoplasmic extensions of muscle cells with contractile fibrils to the nerve cord surface. In amphioxus, myomeres run longitudinally along the length of the body in a “V”-shape.

What is the function of myomeres?

There are three distinct types of myomeres: amphioxine, cyclostomine and piscine. All have in common the function of bending their possessors’ bodies from side to side to provide locomotor force. In all cases pull is applied obliquely to the long axis of the body.

What does Myosepta mean?

a wall of connective tissue that separates the myomeres in lancelets, vertebrate animals, and humans. The myosepta stretch between the axial skeleton and the skin, thus supporting the muscle fibers of the myomeres. (Fish have muscle ossicles in the myosepta.)

What are myotomes in fish?

The muscles of fish are layered, rather than bundled as in the other vertebrates. Each segment, or sheet, of muscles is called a myomere or myotome and is separated from its neighbor by a sheet of connective tissue.

What is Myosepta fish?

In fish, the musculoskeletal system is relatively simple: a connective tissue called myoseptum separates W-shaped myomeres that are arranged in a longitudinal series [1]. Most fish species also have a horizontal septum that divides the myotomal muscle into epaxial and hypaxial domains.

What’s the difference between lancelets and tunicates?

Lancelets refer to the small elongated marine invertebrates that resemble a fish but, lack jaws and obvious sense organs, while tunicates refer to marine invertebrates that have a rubbery or hard outer coat and two siphons to draw water into and out of the body.

What are Myotomes in fish?

What are Myocommata?

my·o·com·ma·ta (mī’ō-kom’ă, -kom’ă-tă), The connective tissue septum separating adjacent myotomes.

Do cephalochordates have hearts?

Circulatory system The most notable difference is that cephalochordates lack a heart. Blood is forced through the closed system by contractile blood vessels (especially one called the ventral aorta) and by blood vessels of the gills.