Muscular Tissue (Cardiac Muscles) Flashcards
It is only found in the heart, specifically the myocardium.
Cardiac muscle tissue
Cardiac muscle tissue is only found in what organ?
heart
Cardiac muscle tissue is only found in the heart, specifically the ____________.
myocardium
It is striated and organized into sarcomeres, possessing the same organization of myofilaments as skeletal muscle. However, cardiac muscle fibers are shorter than skeletal muscle fibers and usually contain only one nucleus, which is located in the central region of the cell.
Cardiac muscles
It shorter than skeletal muscle fibers and usually contain only one nucleus, which is located in the central region of the cell.
cardiac muscle fibers
It also contain many mitochondria. This is necessary as large amounts of ATP are required by the cells and this is produced primarily through aerobic metabolism.
Cardiac muscle fibers
It allows the cardiac muscle cells to contract in a coordinated fashion so that the heart can work as a pump.
intercalated disc
These are part of the sarcolemma and contain two structures important in cardiac muscle contraction: gap junctions and desmosomes
Intercalated discs
2 structures important of intercalated discs in cardiac muscle contraction
gap junctions and desmosomes
It form channels between adjacent cardiac muscle fibers that allow the depolarizing action potential to move between one cardiac muscle cell to the next.
Gap junction
It allows the quick transmission of action potentials and the coordinated contraction of the entire heart. The remainder of the intercalated disc is composed of desmosomes.
Gap junctions
It anchor the ends of cardiac muscle fibers together so the cells do not pull apart during individual fiber contraction.
Desmosomes
Unlike skeletal muscle which is composed of a long row of cells with fused cytoplasm, this muscle is composed of multiple branching cells that are joined by specialized structures, including intercalated discs. These appear as very fine lines between the cardiomyocytes.
cardiac muscle
This joining is called ______________, and in cardiac muscle, it allows the quick transmission of action potentials and the coordinated contraction of the entire heart.
electric coupling,
This network of electrically connected cardiac muscle cells creates a functional unit of contraction called a __________.
syncytium
It is a cell structure that anchors the ends of cardiac muscle fibers together so the cells do not pull apart during the stress of individual fibers contracting Cardiac Muscle.
desmosome
Intercalated discs are part of the cardiac muscle sarcolemma and they contain these two.
gap junctions and desmosomes
Contractions of the heart (heartbeats) are controlled by specialized cardiac muscle cells called ___________ that directly control heart rate.
pacemaker cells
directly control heart rate
pacemaker cells
It cannot be consciously controlled.
cardiac muscle
It respond to signals from the autonomic nervous system (ANS) to speed up or slow down the heart rate.
pacemaker cells
It can also respond to various hormones that modulate heart rate to control blood pressure.
pacemaker cells
The wave of contraction that allows the heart to work as a unit is called a ____________.
functional syncytium
It begins with the pacemaker cells
Functional syncytium
This group of cells is self-excitable and able to depolarize to threshold and fire action potentials on their own, a feature called ______________; they do this at set intervals which determine heart rate.
autorhythmicity
It is striated muscle that is present only in the heart.
Cardiac muscle
intercalated discs that contain ___________ for between cells and __________ to hold the fibers together when the heart contracts.
gap junctions
desmosomes
Depolarization
Gap junstion
hold the fibers together when the heart contracts
Desmosomes
Contraction in each cardiac muscle fiber is triggered by what?
Ca++ ions
It stimulate the spontaneous contraction of cardiac muscle as a functional unit, called a syncytium.
Pacemaker cells
Cardiac muscle cells may also be called what?
cardiocytes / cardiac myocytes / myocardial cells
