[Home] [Free Gift] [Study Tips] [Class Notes] [About Me]
[Awards] [Links & Rings] [Site Map] [Graphics] [Online Tests]
[Home] [Free Gift] [Study Tips] [Class Notes] [About Me]
[Awards] [Links & Rings] [Site Map] [Graphics] [Online Tests]
The three types of muscle = Skeletal Muscle, Cardiac Muscle and Smooth Muscle.
Skeletal Muscle
Skeletal muscle may be called voluntary muscle (because it can be manipulated by conscious effort) or striated muscle (because it appears to be striped). The muscle cell, also called a fiber, contains many nuclei. Cell structures have different names than you'll find in other types of cells, and the muscle cells even have structures that can't be found in other types of cells.
Muscle Cell Structures
|
Sarcolemma |
The cell membrane |
|
Sarcoplasm |
Cytoplasm |
|
Sarcomere |
The contractile unit of the muscle. The sarcomere extends from one Z line of a myofibril to the next Z line of that myofibril. |
|
Z lines (or Z disc) |
Z lines are found in the middle of each I band. |
|
I band |
Thinner, lighter colored striations. |
|
A band |
Thicker, darker color striations. |
|
Myofilaments |
Make up myofibrils |
|
Myofibrils |
Make up muscle cells (fibers) |
|
Connective Tissue coverings of the fibers |
Endomysium: around an individual muscle fiber. Perimysium: around a fascicle (bundle of fibers). Epimysium: around many fascicles. |
Smooth Muscle
Because smooth muscle has no A or I bands, it does not have the striated appearance of skeletal muscle. Smooth muscle is involuntary, meaning that no thought or conscious effort is needed to cause muscle contraction.
Cardiac Muscle
Cardiac muscle is located, as you might guess, only in the heart. It has a striated appearance and is involuntarily controlled. Cardiac muscle also has a feature that is foreign to the other muscle types: intercalated discs.
[Home] [Free Gift] [Study Tips] [Class Notes] [About Me]
[Awards] [Links & Rings] [Site Map] [Graphics] [Online Tests]
