Comparison of morphological structure and function of human upper and lower limb bones, bony junctio

The locomotor system of the human body is composed of bones, bony connections, and skeletal muscles, which have the functions of movement, support, and protection.

Including the girdle bones of the upper extremities: clavicle and scapula; Free upper limb bones: humerus, ulna, radius, carpal bones, metacarpal bones, phalanges.

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 firmly woven together with the periosteum attached to the bone. 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.

The upper and lower limb bones are located in different positions in the human body and have different ranges, and there are no common features between the two.

There are 3 differences between the upper limb bone and the lower limb bone:

First, the position of the two is not known to be the same:

1. Position of upper limb bones: upper part of the body.

2. The position of the bones of the lower limbs: the lower part of the body.

Second, the total number of bones of the two is different:

1. The total number of bones of the limb bones: 64.

2. The total number of bones of the lower limb bones: 31.

Third, the scope of the two is different:

1. The scope of the upper limb bones: the upper limb has a large band including the clavicle and scapula; The free upper limb bones include the humerus, radius, ulna, and hand bones (8 carpal bones, 5 metacarpal bones, 14 phalanges).

2. The scope of lower limb bones: lower limb bones are divided into lower limb bone-bearing bones and free lower limb bones. The lower limb bone, i.e., the hip bone, and the free lower limb bones include the femur, patella, tibia, fibula, 7 tarsus, 5 metatarsal and 14 phalanges.

1. Composition of bone tissue: Bone tissue is a hard connective tissue, which is also composed of cells, fibers and matrix. The fibers are bone glue fibers, and the matrix contains a large amount of solid inorganic salts.

Bone tissue is composed of a large number of calcified interstitial cells and several types of cells. Calcified interstitium of cells is called the bone matrix. There are four types of cells: osteoblasts, osteoblasts, osteocytes and broken mountain bone cells.

Bone cells are the most abundant and are located within the bone matrix, while the other three cells are located at the edge of the bone tissue.

2. Structure of bone tissue: bone tissue is divided into compact bone and cancellous bone. Compact bone is formed by closely arranged bone plates, which are formed by bone glue fibers arranged in parallel and buried in a calcified matrix, with uniform thickness, and between the two bone sedan chair plates, there are a series of neatly arranged fossa, which have multi-protruding bone cells connected to each other by thin tubes.

Closed. 3. The function of bone tissue: supporting the body, protecting internal organs and exercising.

Bones come in different forms. It can be basically divided into four categories: long bones, short bones, flat bones, and irregular bones.

1 Long bones are long tubes that are distributed in the limbs and act as leverage in movement. The long bones have one body and two sock ends. The body, also known as the backbone, is dense in bone, and the cavity in the backbone is called the bone marrow cavity, which contains bone marrow; In a certain part of the body, there is a trophoblast hole where blood vessels enter and exit.

The ends, also known as epiphysis, are more enlarged and have a smooth articular surface, covered by articular cartilage. There is a layer of cartilage between the backbone and the epiphysis of the long bones of children, called epiphyseal cartilage. The epiphyseal cartilage can continue to proliferate and ossify, so that the length of the bone increases.

In adulthood, the epiphyseal cartilage ossification, and there are line-like traces left at the original epiphyseal cartilage, which is called the epiphyseal chain. 2 Short bones are generally cubic in shape, mostly connected in groups, and are located in parts that bear weight and have complex movements, such as the carpal bones and tarsal bones. 3 The flat bones are plate-shaped and distributed on the head, chest, etc.

It often forms the wall of the bony cavity and has a protective effect on the organs in the cavity, such as the cranial bone protects the brain, and the sternum and ribs protect the heart and lungs. 4 Irregular bone Irregular morphology, such as vertebrae. Some irregular bones have air-containing cavities called air-containing bones, such as maxillary socks and ethmoid bones located around the nasal cavity, which can resonate when pronounced and can reduce the weight of the bone.