How does cardiac muscle resemble skeletal muscle

The remainder of the intercalated disc is composed of desmosomes. A desmosome 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 Figure. Contractions of the heart heartbeats are controlled by specialized cardiac muscle cells called pacemaker cells that directly control heart rate. Although cardiac muscle cannot be consciously controlled, the pacemaker cells respond to signals from the autonomic nervous system ANS to speed up or slow down the heart rate.

The pacemaker cells can also respond to various hormones that modulate heart rate to control blood pressure. The wave of contraction that allows the heart to work as a unit, called a functional syncytium, begins with the pacemaker cells.

This group of cells is self-excitable and able to depolarize to threshold and fire action potentials on their own, a feature called autorhythmicity ; they do this at set intervals which determine heart rate. 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.

Pacemaker cells stimulate the spontaneous contraction of cardiac muscle as a functional unit, called a syncytium. What would be the drawback of cardiac contractions being the same duration as skeletal muscle contractions? An action potential could reach a cardiac muscle cell before it has entered the relaxation phase, resulting in the sustained contractions of tetanus.

This can be contrasted with the density of adipose tissue fat , which is 0. Privacy Policy. Skip to main content. Chapter 8: Muscle Strength and Endurance. Search for:. Key Takeaways Key Points Skeletal muscles are attached to bones and allow voluntary movement of the body. Smooth muscles, which generate involuntary movement, form part of the walls of the esophagus, stomach, intestines, bronchi, uterus, urethra, bladder, and blood vessels, among other portions of the body.

Cardiac muscle is involuntary and found only in the heart. Skeletal muscle is striated in regular, parallel bundles of sarcomeres. Cardiac muscle is striated, but the bundles are connected at branching, irregular angles called intercalated discs. But cardiac muscles are involuntary.

Explanation: Majority of striated muscles act quickly. Related questions Why do muscles work in pairs? How do muscles and bones work together? How do muscle cells differ from nerve cells? What are some examples of muscles? What are muscles? Why is skeletal muscle called voluntary muscle? How many smooth muscles are in the human body? How do cardiac and smooth muscles differ from skeletal?