What are cardiac muscle fibers connected by?
Cardiac muscle cells form a highly branched cellular network in the heart. They are connected end to end by intercalated disks and are organized into layers of myocardial tissue that are wrapped around the chambers of the heart.
What is the name of the join between cardiac muscle cells?
Intercalated discs
Intercalated discs are small connections that join cardiac muscle cells (cardiomyocytes) to each other.
What type of junction is cardiac muscle fibers?
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.
What is the purpose of the Endocardium?
Anatomic function: A tissue covering the inside of the heart, the endocardium keeps the blood flowing through the heart separate from the myocardium, or cardiac muscles. It also lines the valves, which open and close to regulate blood flow through the chambers of the heart.
Where does excitation contraction coupling occur?
skeletal muscle fibres
First coined by Alexander Sandow in 1952, the term excitation-contraction coupling (ECC) describes the rapid communication between electrical events occurring in the plasma membrane of skeletal muscle fibres and Ca2+ release from the SR, which leads to contraction.
How are the intercalated discs involved in the contraction of cardiac muscles?
Intercalated discs are part of the sarcolemma and contain two structures important in cardiac muscle contraction: gap junctions and desmosomes. A gap junction forms channels between adjacent cardiac muscle fibers that allow the depolarizing current produced by cations to flow from one cardiac muscle cell to the next.
How do cardiac muscle Fibres contract as a unit?
Cardiac muscle fibers contract via excitation-contraction coupling, using a mechanism unique to cardiac muscle called calcium -induced calcium release. Excitation-contraction coupling describes the process of converting an electrical stimulus ( action potential ) into a mechanical response (muscle contraction).
Which type of cell connection joins heart muscle cells quizlet?
Intercalated disks: The gap junctions between cardiac muscle cells are found in specialized cell-to-cell connections called intercalated disks.
Which layer of the heart is composed of cardiac muscle?
Myocardium
Myocardium. Myocardium (myo-cardium) is the middle layer of the heart wall. It is composed of cardiac muscle fibers, which enable heart contractions. The myocardium is the thickest layer of the heart wall, with its thickness varying in different parts of the heart.
What makes up the endocardium?
The endocardium is composed of simple squamous epithelial cells which form the inner lining of the heart chambers. The endocardium connects to blood vessels that supply the heart muscle and contributes to the regulation of heart contractions.
Where do striated muscle fibers get their striations from?
The striated appearance of skeletal muscle tissue is a result of repeating bands of the proteins actin and myosin that are present along the length of myofibrils. Dark A bands and light I bands repeat along myofibrils, and the alignment of myofibrils in the cell causes the entire cell to appear striated or banded.
In what sequence does excitation and contraction of muscle fiber take place?
The sequence of events in skeletal twitch muscle fibres involves: (1) initiation and propagation of an AP along the plasma membrane, (2) radial spread of the potential along the transverse tubule system (T-tubule system), (3) dihydropyridine receptors (DHPR, L-type Ca2+ channel CaV1.1)-mediated detection of changes in …