The structural characteristics of skeletal muscle, skeletal muscle can be divided into different str

A typical muscle that can be divided into the abdomen in the middle and the tendons at both ends.

The abdomen is the main part of the muscle, which is composed of muscle bundles composed of striated muscle fibers, which are red, soft and contractile.

The tendons are corded or flat-banded, composed of parallel bundles of collagen fibers, white in color, shiny, but inflexible, and the tendons are attached to the bone and periosteum.

Securely woven together. The abdomen and tendons of the latissimus muscle are membranous, and their tendons are called aponeurosis. The surface of the abdomen is covered with a connective tissue adventitia, which fuses with tendon tissue at both ends.

The morphology of muscles is different, and there are basic types such as long, brev, latis, and orbicularis oculi. The long muscles are mostly found in the limbs, mainly fusiform or flat bands, the arrangement of the muscle bundles is consistent with the long axis of the muscles, the amplitude of contraction is large, and large movements can be produced, but because the number of cross-sectional muscle bundles is relatively small, the contraction force is also small.

There are also some muscles with long tendons, and the muscle bundles are arranged obliquely on both sides of the tendon, similar to the feathers called feathers called feathers (such as rectus femoris), or obliquely arranged on one side of the tendon, called semi-pinnate muscles (such as semimembranous muscles, flexor pollicis longus), the number of these muscles in their physiological transverse muscle bundles greatly exceeds that of fusiform or belt muscles, so the contractility is larger, but because the muscle bundles are short, the amplitude of movement is small.

Brevis muscles are more common in the hands, feet, and intervertebral areas. The latissimus muscle is mostly located on the trunk and forms the wall of the body cavity. The orbicularis oris muscle surrounds the openings such as the eyes and mouth.

Skeletal muscle, also known as striated muscle, is a type of muscle. The human body has more than 600 pieces of skeletal muscle. Muscle cells are fibrous, unbranched, with distinct striation, numerous nuclei, and are located below the cell membrane. Inside the muscle cells there are many filamentous myofibrils arranged in parallel along the long axis of the cell.

1. Flat muscle.

Muscle fibers are parallel and often have aponeurosis, such as the external oblique muscle.

2. Pinnate muscles.

Muscle bundles are arranged in a feathery shape and can be divided into semi-pinnae, feather, or multiple pinnae, such as the deltoid.

3. Fusiform muscle.

Spindle-shaped (thick and rounded abdomen with tapering ends), e.g., biceps.

4. Square muscle. It is square in shape and has 4 approximately equal sides, e.g., pronator anterior muscle.

5. Annular muscle or sphincter.

Distribution of openings or holes around the body. These openings are narrowed when muscles contract, for example, the orbicularis oculi muscle can close the palpebral fissure.

Head and neck, trunk, and limb muscles

The motivation for people to exercise comes from skeletal muscles.

Skeletal muscle is made up of muscle cells arranged in bundles.

The length of each cell is different, and the cells are closely arranged with each other, and the length is complementary.

The skeletal muscles of the human body can be divided into head and neck muscles, trunk muscles and limb muscles according to different structures.