What are intercalated discs and what is their function?

Asked By: Gra├žas Fellehner | Last Updated: 30th April, 2020
Category: medical health heart and cardiovascular diseases
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muscle cells, unique junctions called intercalated discs (gap junctions) link the cells together and define their borders. Intercalated discs are the major portal for cardiac cell-to-cell communication, which is required for coordinated muscle contraction and maintenance of circulation.

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Regarding this, what are intercalated discs and why are they important?

Intercalated discs are unique structural formations found between the myocardial cells of the heart. They play vital roles in bonding cardiac muscle cells together and in transmitting signals between cells.

Also Know, what are the intercalated discs that are found in cardiac muscle? Cardiac muscle is striated muscle that is present only in the heart. Cardiac muscle fibers have a single nucleus, are branched, and joined to one another by intercalated discs that contain gap junctions for depolarization between cells and desmosomes to hold the fibers together when the heart contracts.

Consequently, what does intercalated discs mean?

Intercalated discs are microscopic identifying features of cardiac muscle. Intercalated discs support synchronized contraction of cardiac tissue. They occur at the Z line of the sarcomere and can be visualized easily when observing a longitudinal section of the tissue.

Why are intercalated discs only found in cardiac muscle?

Cardiac muscle fibers cells also are extensively branched and are connected to one another at their ends by intercalated discs. An intercalated disc allows the cardiac muscle cells to contract in a wave-like pattern so that the heart can work as a pump.

34 Related Question Answers Found

What are the 3 layers of the heart muscle?

The wall of the heart consists of three layers: the epicardium (external layer), the myocardium (middle layer) and the endocardium (inner layer). The epicardium is the thin, transparent outer layer of the wall and is composed of delicate connective tissue.

What are Desmosomes?

Desmosomes are intercellular junctions that provide strong adhesion between cells. Because they also link intracellularly to the intermediate filament cytoskeleton they form the adhesive bonds in a network that gives mechanical strength to tissues.

What do T tubules do?

The function of T-TUBULES is to conduct impulses from the surface of the cell (SARCOLEMMA) down into the cell and, specifically, to another structure in the cell called the SARCOPLASMIC RETICULUM. But the primary function of the SARCOPLASMIC RETICULUM is to STORE CALCIUM IONS.

What is the difference between striations and intercalated discs?

Cardiac muscle is only found in the heart. Its fibers are longer than they are wide, and they are striated, like skeletal muscle fibers. But, unlike skeletal muscle fibers, cardiac muscle fibers have distinct ends to them, called intercalated discs. No striations are visible in smooth muscle under the microscope.

What do intercalated discs look like?

Contains gap junctions that join cardiac muscle cells to allow potentials to spread throughout the network in the heart. Intercalated discs look like dark, short lines. They look like long, (thicker than intercalated disc), lines. Striations are present in the heart to allow the heart to contract when pumping.

How does the heart never get tired?

Cardiac muscle resists fatigue so well because it's got more mitochondria than skeletal muscle. With so many power plants at its disposal, the heart doesn't need to stop and chill out. It also has a steady supply of blood bringing it oxygen and nutrients.

What cells are in the heart?

There are two types of cells within the heart: the cardiomyocytes and the cardiac pacemaker cells. Cardiomyocytes make up the atria (the chambers in which blood enters the heart) and the ventricles (the chambers where blood is collected and pumped out of the heart).

Is smooth muscle voluntary?

Smooth muscle is non-striated, although it contains the same myofilaments they are just organized differently, and involuntary. Smooth muscle myocytes are spindle shaped with a single centrally located nucleus. Both cardiac and smooth muscle are involuntary while skeletal muscle is voluntary.

What is sarcoplasmic reticulum?

The sarcoplasmic reticulum (SR) is a membrane-bound structure found within muscle cells that is similar to the endoplasmic reticulum in other cells. The main function of the SR is to store calcium ions (Ca2+).

How do gap junctions work?

Gap junction. Gap junctions are a specialized intercellular connection between a multitude of animal cell-types. They directly connect the cytoplasm of two cells, which allows various molecules, ions and electrical impulses to directly pass through a regulated gate between cells.

What is special about the heart muscle?

Cardiac muscle tissue works to keep your heart pumping through involuntary movements. This is one feature that differentiates it from skeletal muscle tissue, which you can control. It does this through specialized cells called pacemaker cells. These control the contractions of your heart.

Where is smooth muscle found?

Smooth muscle is found in the walls of hollow organs like your intestines and stomach. They work automatically without you being aware of them. Smooth muscles are involved in many 'housekeeping' functions of the body. The muscular walls of your intestines contract to push food through your body.

What is the function of intercalated discs quizlet?

Cardiac contractile cells have intercalated discs that permit ions to pass between the cells, which transmits the electrical impulse rapidly. These anatomical features that are necessary for the heart to beat are not found in smooth muscle cells.

Where are gap junctions found in cardiac muscle?

Intercellular junctions and the cardiac intercalated disk. Severs NJ. Cardiac muscle cells are equipped with three distinct types of intercellular junction--gap junctions, "spot" desmosomes, and "sheet" desmosomes (or fasciae adherentes)--located in a specialized portion of the plasma membrane, the intercalated disk.

Why are striations present in heart muscle?

The regular organization of myofibrils into sarcomeres gives cardiac muscle cells a striped or striated appearance when looked at through a microscope, similar to skeletal muscle. These striations are caused by lighter I bands composed mainly of a protein called actin, and darker A bands composed mainly of myosin.

Where is cardiac muscle found?

Cardiac muscle cells are located in the walls of the heart, appear striated, and are under involuntary control. Smooth muscle fibers are located in walls of hollow visceral organs, except the heart, appear spindle-shaped, and are also under involuntary control.