muscle
To view the entire topic, please sign in or purchase a subscription.
Nursing Central is an award-winning, complete mobile solution for nurses and students. Look up information on diseases, tests, and procedures; then consult the database with 5,000+ drugs or refer to 65,000+ dictionary terms. Explore these free sample topics:
-- The first section of this topic is shown below --
(mŭs′ĕl )
[L. musculus, diminutive of mus, mouse]
A type of tissue composed of contractile cells. Each muscle cell is filled with parallel actin and myosin filaments. When activated by an internal release of calcium, the filaments use the energy in adenosine triphosphate to crawl along each other in opposite directions. This movement shortens the length of the cell, which then contracts.
The three classes of myocytes (muscle cells) are skeletal (striated), cardiac (striated), and smooth; most human muscle is skeletal. A typical muscle has a central portion (the belly) and two or more attachment ends with tendons. The more stationary of the attachments is called the origin; the more movable attachment is called the insertion.
SELECTED MUSCLES OF THE BODY 
MUSCLE FIBER 
MORPHOLOGICAL FORMS OF MUSCLE
Comparison of Properties of Three Types of Muscle
| Smooth | Cardiac | Striated | |
| Synonyms | Involuntary | Myocardial | Voluntary |
| Nonstriated | Skeletal | ||
| Visceral | |||
| Fibers | |||
| Length (in/m) | 50-200 | 25,000 | |
| Thickness (in/m) | 4-8 | 75 | |
| Shape | Spindles | Cylinders | |
| Markings | No striation | Striation | Marked striation |
| Nuclei | Single | Single | Multiple |
| Effects of cutting related nerve | Slight | Regulation of heart rate is lost | Complete paralysis |
-- To view the remaining sections of this topic, please sign in or purchase a subscription --
(mŭs′ĕl )
[L. musculus, diminutive of mus, mouse]
A type of tissue composed of contractile cells. Each muscle cell is filled with parallel actin and myosin filaments. When activated by an internal release of calcium, the filaments use the energy in adenosine triphosphate to crawl along each other in opposite directions. This movement shortens the length of the cell, which then contracts.
The three classes of myocytes (muscle cells) are skeletal (striated), cardiac (striated), and smooth; most human muscle is skeletal. A typical muscle has a central portion (the belly) and two or more attachment ends with tendons. The more stationary of the attachments is called the origin; the more movable attachment is called the insertion.
SELECTED MUSCLES OF THE BODY
MUSCLE FIBER
MORPHOLOGICAL FORMS OF MUSCLE
Comparison of Properties of Three Types of Muscle
| Smooth | Cardiac | Striated | |
| Synonyms | Involuntary | Myocardial | Voluntary |
| Nonstriated | Skeletal | ||
| Visceral | |||
| Fibers | |||
| Length (in/m) | 50-200 | 25,000 | |
| Thickness (in/m) | 4-8 | 75 | |
| Shape | Spindles | Cylinders | |
| Markings | No striation | Striation | Marked striation |
| Nuclei | Single | Single | Multiple |
| Effects of cutting related nerve | Slight | Regulation of heart rate is lost | Complete paralysis |
There's more to see -- the rest of this entry is available only to subscribers.