Musculoskelatal System Flashcards
Types of muscle in the body
Visceral (weakest), cardiac and skeletal muscle
Visceral muscle
Involuntary muscles, such as visceral ones, are controlled by the unconscious part of the brain. Because cells show up under a microscope, it is also identified as a smooth muscle.
Cardiac muscle
This muscle type is exclusive to the heart and allows it to pump blood throughout the body. It cannot be voluntarily controlled, but differs from visceral muscle in that it is stronger.
What factor contributes to strength of cardiac muscle tissue?
Individual muscle cells, called cardiomyocytes, are joined together by inter calculated disks.
Myofibrils
Constituents of muscle fibers responsible for contractions in skeletal muscle. Myofibrils are composed of small subunits of protein fibers called sacromeres.
Type I Skeletal Muscle
Muscles contract slowly and are used for stamina and posture; these muscles rely on sugars broken down by aerobic respiration for energy. This type of muscle is resistant to fatigue as well.
Type II Muscle
Muscles contract more quickly and are broken down into two types, type A and type B. While Type IIA muscles are found in the legs and have more endurance, type IIB muscles, which are found in the arms. Type IIB muscles are stronger than IIA muscles.
How do skeletal muscles work?
The muscle responsible for the action, the agonist, pairs with the muscle that opposes that action, the antagonist. When the two contract at the same time, no moment results. Muscles that support the agonist, called synergistic, are bound to the same bone, stabilize movement, and reduce unnecessary movement. Fixators provide additional support by stabilizing the origin.
Muscle nomenclature can be determined by
The region of the body in which they are located; the number of regions; the bones to which the muscles are attached; functionality and/or their size.
Motor neurons
Neurons that regulate muscles. If they control a number of muscles, it is called a motor unit.
Motor neurons facilitate
Isotonic muscle contraction; isometric muscle contraction; muscle tone; twitch contraction, temporal summation and tetanus.
Processes through which muscles are able to obtain energy for movement
Lactic acid fermentation and aerobic respiration; these processes generate adenosine triphosphate (ATP). When ATP is converted to ADP, energy is released.
Myoglobin
Storage molecule for oxygen and also enables muscles to perform aerobic respiration when there is lack of blood flow to muscle tissue.
Creatine phosphate
Creates ATP by donating a phosphate group to ADP.
Glycogen
Polymer of glucose that helps muscles make ATP
Which other molecules help muscles generate ATP for energy?
Myoglobin, creatine, and glycogen.
Function of bones and joints
Provide support and protection; facilitate movement; create blood cells; store fat, iron and calcium; guide growth of the body
Bone Matrix
Non-living part of bone tissue composed of water, collagen, protein, calcium phosphate and calcium carbonate crystals
Osteocytes
Living bone cells found at the edges and in small cavities of bone.
Layers of bone
Periosteum, compact bone, and trabeculae
Periosteum
Topmost layer of bone that serves as connective tissue. This layer consists of collagen fibers that hold the tendons and muscles together. It also contains stem and osteoblast cells for growth and bone repair. Nervous tissue, nerve endings and blood vessels are present in this layer as well.
Compact Bone
This bone layer is underneath the periosteum and provides strength to the bone. Composed of mineral salts and collagen fibers, this section has many cavities in which osteocytes can be found.
