In: Anatomy and Physiology
6. Compare/contrast cardiac muscle with skeletal muscle. In a figure show the ion fluxes associated with an action potential in contractile cardiac muscle fibers.
8. Compare the electrical activity (ion current fluxes) in cardiac pacemaker cells with that found in cardiac muscle cells. Specify an additional role for calcium in the cardiac muscle cell action potential. Use a figure.
11. When looking at the extrinsic control of the arterioles, explain how sympathetic stimulation (stress) affects the blood flow and diameter of vessels in the heart vs circulatory system when comparing alpha-1 receptors and beta-2 adrenergic receptors. What are the corresponding ligands (hint…abcd)?
Ans 6: Cardiac muscles are involuntary while skeletal muscles are voluntary in nature. Cardiac muscle is striated with bundles are connected at branching, irregular angles called intercalated discs while skeletal muscle is striated in regular, parallel bundles of sarcomeres. Cardiac muscle tissue is short, branched with single central nucleus while skeletal muscle tissue is long cylindrical fiber with many peripherally located nuclei.
The major areas of differences between cardia and skeletal muscles are as follows:
Properties | Cardia Muscle | Skeletal Muscle |
Found | In heart only | Attached to bones throughout body |
Length | Shorter | Longer |
Control | Autonomic nervous system | Somatic nervous system |
Shape | Smei-spindle | Cylindrical |
Function | Pumping of blood | Movement of the body |
Cell type | Uninucleated | Multinucleated |
Contraction Speed | Slow | Fast |
Contracts | Without neural stimulation | With neural stimulation |