Full Title: Structural Muscle Groups
Author: Goldie Berencsi
Date of Publication: December 30, 2011
Research Paper Text:
The muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. They are classified as skeletal, cardiac, or smooth muscles. Their function is to produce force and cause motion.
Smooth muscle= Smooth muscles are found within the internal organs such as the intestines, stomach, and bladder. They are involuntary muscles and are under the control of the autonomic nervous system.
There are 3 types of muscle tissue:
- Smooth muscle= Smooth muscles are found within the internal organs such as the intestines, stomach, and bladder. They are involuntary muscles and are under the control of the autonomic nervous system.
- Skeletal muscle= These muscles are called striated muscles and are voluntary muscles. They predominately attach to portions of the skeleton. They are involved with such things as walking, eating, tail wagging and eye movement.
- Cardiac muscle= Cardiac muscle fibers are found in the heart and are involuntary muscles. Cardiac muscle is unique in that it is striated muscle, like skeletal muscle, but is not under voluntary control.
Each individual muscle is composed of many cells held together by connective tissue. 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. Once a signal or an impulse travels down the nerve to the muscle, the muscle fiber changes chemical energy into mechanical energy, and the result is muscle contraction.The muscles are located throughout the entire skeletal system and are attached to bones, other muscles and skin.
They account for about half the weight of an animal. Parts of the walls of hollow internal organs such as the heart, stomach and intestines, and blood vessels are composed of smooth muscles.
The muscular system is one of the largest systems in the dog’s body.
Each dog has 9 muscle groups, they are the head. neck, thorax, abdomen, pelvic area, pelvic and thoracic extremities, trunk and tail. Each muscle is connected to the bone by tendons and ligaments. The muscles can be under voluntary or involuntary control. Voluntary muscles, such as those found in the arms and legs, can be controlled by thought. Involuntary muscles are those that are automatically controlled by the nervous system and cannot be moved at will.
The primary function of muscles is to bring about movement to all or part of the dog’s body. Muscle is used to stabilize joints to prevent their collapse under a load. Smooth muscles maintain continence of the bladder and propel food through the bowel. Muscles also help to generate heat by shivering. Voluntary muscles can contract and pull, but they cannot push, so they must work in pairs that flex and extend. Extensor muscles straighten the limbs and attach to the bones, so the bones act as levers. The flexor muscles, which bend the joints, act to pick up the limb. Their partners, the extensor muscles, in turn contract to bring the limb back down. The abductor muscles move the limbs away from the midline, and the adductor muscles move the limbs toward the midline.