2. The muscular system of rat

Characteristics of the rat muscular system

Muscle is a soft tissue in the body of rat. Its main purpose is to produce force and motion. Muscles are responsible for maintaining posture, physical movement and movement of internal organs. Tendons connect soft contracting muscles to hard bones.

Muscles of rat can be under voluntary or involuntary control. Voluntary muscles can be controlled by thought. Involuntary muscles are those that are automatically controlled by the nervous system and cannot be moved at will.

There are three main types of rat's muscular tissue:

1) smooth or visceral muscle, 2) striated or skeletal muscle, 3) cardiac muscle Smooth (visceral) muscle is involuntary muscles, that can contract slowly, they make up the walls of the internal organs. Smooth muscle tissues consist of long cells. Smooth muscle fibers are bound into bundles by connective tissue, which contains blood vessels and nerves.

Striated muscles are most necessary for manipulation of the bones of the skeleton. Skeleton muscles are voluntary muscles. They are involved with such activities as walking, eating, tail motion and eye movement. Striated muscle tissue consists of large fibers in the form of bundles. Skeletal muscles attach to bones by means of connective tissue tendons, which are elastic and strong. When muscles contract, they pull on the tendons, which then pull on the bones and cause the limbs to move. Each muscle fiber receives its own nerve impulses, which trigger various motions.

A characteristic feature of cardiac (heart) muscle is that fibers have neither a beginning nor an end. The heart is simply a huge net of muscles in which all elements are continuous with each other. Cardiac muscles have the force of contraction of skeletal muscle. Cardiac muscle is under complete involuntary control.

Muscles of the head - include the muscles of the muzzle and muscles of mastication, suboccipital muscles, muscles of the eye, tongue and palate. The last three muscle groups are discussed in the sections on the structure of the eye and oral cavity.

Facial muscles - include a variety of superficial muscles of the head surrounding the eyes, mouth, and ears. The neck muscle, which occupies most of the lateral surface of the head, is also considered here.

Neck muscles - include the neck muscles themselves, the muscles associated with the hyoid apparatus - the suprahyoid and infrahyoid muscles, as well as the muscularis tunic of the pharynx and the muscles of the larynx. The last two muscle groups are considered when describing the pharynx and larynx.

Back muscles- include the trapezius, latissimus dorsi, rhomboids, scapulotransversus, serratus muscles, as well as muscles that are part of the complexes: the erector spinae muscle, the transverse spinal muscle and the interspinous muscles.

The muscles of the chest include the following muscles of the chest wall: superficial and deep pectoralis, subclavian, ventral serratus muscle of the chest, muscles that lift the ribs, external and internal intercostal muscles, transverse muscle of the chest.

Diaphragm- muscle-tendon septum between chest and abdominal cavities; its shape is dome-shaped, it distinguishes between peripheral muscle and central tendon sections. In the muscular section of the lumbar part - the diaphragm is attached to the ventral surface of bodies by two legs: the right one (the large one begins with a long tendon from the lumbar vertebra; spreading, surrounds the esophagus) - and the left (the smaller of the two). Between the tendons of the legs dorsally at the level of the vertebral bodies there is an aortic opening - hiatus aorticus - for the passage of the aorta and thoracic duct. In the cranioventral part of the right leg there is an esophageal opening - hiatus esophageus, through which the esophagus and vagus nerve pass from the chest cavity to the abdominal cavity. [7]

Tendons and Ligaments: How to Prevent Tendon/Ligament Injury in a horse.

Ligaments and tendons are part of the musculoskeletal system, with ligaments attaching bones to bones and tendons muscles to bones. Ligaments and tendons are made of dense fibrous connective tissue. Tendon and ligament injuries are common in racehorses, what is associated with a high load on the limbs. The reasons are mechanical in nature: bundles of fibers can shift in relation to each other, during the support for the suspensory ligament of the put joint and the tendon with perforation; during the forward movement for carpal fusion and perforating tendon.

Types of tendon injuries are traumatic tendinitis: rest contributes to full recovery, tendinitis caused by fatigue, overwork: rest helps to improve, but the subsequent exploitation of the animal leads to relapses. For example: a tendon with a perforation, a suspensory ligament of the put joint in young horses, carpal fusion in old ones.

Progressive degenerative tendinitis (aging) rest allows you to reduce the pain, but the damage remains the same or progresses. For example: the suspending ligament of the put joint on the hind limbs.

The treatment can include orthopedic intervention, rest in the stall and in the pasture and competent exercise, carried out under strict control.