What are the functional units of Myofibrils?

The contractile functional unit of the myofibril is called the sarcomere, which is approximately 1.6–2.0 μm in length.

What is the functional unit of the liver?

The functional unit of the liver is the lobule. Each lobule is hexagonal and a portal triad (portal vein, hepatic artery, bile duct) sits at each corner of the hexagon.

What is the function of the M line?

Thin filaments from neighbouring sarcomeres are crosslinked in the Z-disc, and thick filaments within a sarcomere are crosslinked in the M-line. These links hold the filaments in register as the fibres contract, and prevent them coming out of alignment when fibres are stretched.

Where is Z line present?

Z-line is defined to be the lateral boundaries of a sarcomere. In muscles, Z-lines are found as a series of dark lines. It is found in the centre of each I-band that bisects the I-band.

What is functional unit muscle?

– The structural and functional unit of muscle fiber is the sarcomere. – Each myofiber again consists of actin and myosin molecules which help in the muscle contraction.

What is known as functional unit of muscle?

The basic functional unit of the skeletal muscle. Myofibrils are assembled of repeated structures called sarcomeres – the smallest functional unit of muscle fiber. The border between two neighboring sarcomeres is called the Z-line (also known as the Z-disc or Z-band).

What is structural and functional unit of liver?

Hepatocytes are the cells found in the liver involved in accept and filtration of blood. – Now, as mentioned above the structural and functional unit of a liver is hepatic lobules.

What is the function of Nebulin?

Nebulin is an actin-binding protein which can bind upto 200 actin molecules. Nebulin length is proportional to the length of the thin filament. It may function as a regulator of thin filament length during sarcomere assembly.

What is Sarcolemmal?

The sarcolemma is the plasma membrane of the muscle cell and is surrounded by basement membrane and endomysial connective tissue. The sarcolemma is an excitable membrane and shares many properties with the neuronal cell membrane.

What does an irregular Z line mean?

An irregular Z-line was defined as any discrete tongue or exaggerated waviness of the Z-line which extended proximally less than 1 cm. Two to 4 biopsies were obtained with standard forceps; biopsies were taken in 4 quadrants every 2 cms for segments >3 cms.

What does Z line mean in medical terms?

A demarcation line, the squamocolumnar (SC) junction or “Z-line”, represents the normal esophagogastric junction where the squamous mucosa of the esophagus and columnar mucosa of the stomach meet (Figure 2).

What is the basic functional unit of a myofibril?

Myofibrils are made up of sarcomeres, the functional units of a muscle. The function of the myofibril is to perform muscle contraction via the sliding-filament model. When muscles are at rest, there is incomplete overlap between the thin and thick filaments, with some areas containing only one of the two types.

Which is the functional unit of the liver?

Hepatic Histology: The Acinus The hepatic acinus is the functional unit of the liver. The hepatic acinus is the functional unit of the liver. The acinus is more difficult to visualize than the lobule, but represents a unit that is of more relevance to hepatic function because it is oriented around the afferent vascular system.

What makes up the internal structure of the liver?

The internal structure of the liver is made of around 100,000 small hexagonal functional units known as lobules. Each lobule consists of a central vein surrounded by 6 hepatic portal veins and 6 hepatic arteries.

Which is the smallest functional unit of muscle fiber?

Myofibrils are assembled of repeated structures called sarcomeres – the smallest functional unit of muscle fiber. Each sarcomere is formed of actin (called thin) and myosin (called thick) filaments arranged in a precise order and of protein complexes which support the filament structures. Click to see full answer.