Structure Function Of The Body
Structure/function claims for conventional foods focus on effects derived from nutritive value, while structure/function claims for dietary supplements may focus on non-nutritive as well as nutritive effects. FDA is likely to interpret the dividing line between structure/function claims and disease claims in a similar manner for conventional foods as for dietary supplements.
Structure Function of the Body
Digestion is important because your body needs nutrients from the food you eat and the liquids you drink in order to stay healthy and function properly. Nutrients include carbohydrates, proteins, fats, vitamins, minerals and water. Your digestive system breaks down and absorbs nutrients from the food and liquids you consume to use for important things like energy, growth and repairing cells.
The main organs that make up the digestive system (in order of their function) are the mouth, esophagus, stomach, small intestine, large intestine, rectum and anus. Helping them along the way are the pancreas, gall bladder and liver.
The mouth is the beginning of the digestive tract. In fact, digestion starts before you even take a bite. Your salivary glands get active as you see and smell that pasta dish or warm bread. After you start eating, you chew your food into pieces that are more easily digested. Your saliva mixes with the food to begin to break it down into a form your body can absorb and use. When you swallow, your tongue passes the food into your throat and into your esophagus.
The pancreas secretes digestive enzymes into the duodenum that break down protein, fats and carbohydrates. The pancreas also makes insulin, passing it directly into the bloodstream. Insulin is the chief hormone in your body for metabolizing sugar.
The liver has many functions, but its main job within the digestive system is to process the nutrients absorbed from the small intestine. Bile from the liver secreted into the small intestine also plays an important role in digesting fat and some vitamins.
Your spine, or backbone, is your body's central support structure. It connects different parts of your musculoskeletal system. Your spine helps you sit, stand, walk, twist and bend. Back injuries, spinal cord conditions and other problems can damage the spine and cause back pain.
Your spine is a complex structure of small bones (vertebrae), cushioning disks, nerves, joints, ligaments and muscles. This part of your anatomy is susceptible to injury, arthritis, herniated disks, pinched nerves and other problems. Back pain can affect your ability to enjoy life. Your healthcare provider can help ease back pain and offer suggestions to strengthen the muscles that support your back and prevent back injuries.
Epithelial tissue is a highly cellular tissue that overlies body surfaces, lines cavities, and forms glands. In addition, specialized epithelial cells function as receptors for special senses (smell, taste, hearing, and vision). Epithelial cells are numerous, exist in close apposition to each other, and form specialized junctions to create a barrier between connective tissues and free surfaces. Free surfaces of the body include the outer surface of internal organs, lining of body cavities, exterior surface of the body, tubes and ducts. The extracellular matrix of epithelial tissue is minimal and lacks additional structures. Although epithelial tissue is avascular, it is innervated.
Cilia are small processes found in the respiratory tract and female reproductive tract. Their complex structure facilitates movement that brushes small structures through the lumen of either the trachea or Fallopian tubes. Stereocilia are similar to cilia in size and shape, however they are immotile and more frequently found in the epithelium of the male reproductive tract, specifically in the ductus deferens and the epididymis.
The lateral surfaces of epithelial cells are located between adjacent cells. The most notable lateral surface structures are junctions. Adhering junctions link the cytoskeleton of neighboring cells to produce strength in the tissue. Desmosomes can be thought of as spot-welding for epithelial tissues. They are usually located deep to adhering junctions and are found in locations subject to stresses. For example in the stratified epithelium of the skin.
Tight junctions form a solid barrier to prevent movement of molecules between adjacent epithelial cells. Tight junctions are found in the simple columnar epithelium of the gut tube to regulate absorption of nutrients. Finally, gap junctions perform the opposite function. Gap junctions allow small molecules and structures to pass freely between cells. For example, gap junctions in cardiac muscle tissue allow for coordinated contraction of the heart.
Connective tissue is the most abundant tissue type in the body. In general, connective tissue consists of cells and an extracellular matrix. The extracellular matrix is made up of a ground substance and protein fibers. So, in a more detailed way, all connective tissue apart from blood and lymph consists of three main components: cells, ground substance and fibers.
Classification of connective tissue is based upon two characteristics: the composition of its cellular and extracellular components and its function in the body. Tissues are either classified as proper, embryonic, or specialized.
Embryonic connective tissue, derived from mesoderm, is the precursor to many connective tissues in the adult body. It is categorized into two subtypes: mesenchyme and mucous connective tissue. Mesenchyme is found within the embryo. Mesenchymal cells are spindle shaped with processes extending from either end. The cell processes connect to those of other mesenchymal cells through gap junctions. Very thin, scattered collagen fibers are present, but they are not particularly strong reflecting the limited stress placed on the tissues of the developing embryo.
Bone tissue is unique in that its extracellular matrix is mineralized. Calcium phosphate, in the form of hydroxyapatite crystals, is responsible for the mineralization of bone and creates a very strong tissue able to support and protect the body.Blood is a fluid connective tissue that transports gases, nutrients, and wastes throughout the body. The fluid extracellular matrix of blood is made up of plasma, which constitutes slightly more than half of the tissue volume. The cells of blood tissue are classified as erythrocytes, leukocytes, and thrombocytes. Erythrocytes, or red blood cells, carry oxygen and carbon dioxide through the cardiovascular system. Leukocytes, or white blood cells, are responsible for the immune and allergic responses. Thrombocytes, or platelets, form clots and initiate the repair of injured blood vessels.
Skeletal muscle is responsible for the voluntary movement of the body. For example, movement of the limbs, skin of the face, and orbits. Contraction of skeletal muscle tissue is rapid and strong. Cells are large, cylindrical, and elongated. In embryonic development, myoblasts fuse together to form one larger muscle cell, resulting in syncytial, multinucleated cells. Nuclei of skeletal muscle cells are peripheral and ovoid. When viewed under a microscope, the arrangement of actin and myosin gives skeletal muscle a striated appearance.
Cardiac muscle is found in the heart wall also known as myocardium. Like skeletal muscle, actin and myosin also give cardiac muscle a striated appearance. The movement that cardiac muscle cells provide is involuntary and coordinated by gap junctions. A major defining characteristic of cardiac muscle tissue is the presence of intercalated disks. Cardiac muscle cells are elongated and branched. Intercalated disks are present at the junctions between two cells. Although gap junctions allow this tissue to function as a syncytium, each cell has one, centrally located nucleus.
Neurons tend to have a large cell body, or soma, and long projections used in transmitting information. These projections are referred to as axons or dendrites. Axons send impulses away from the soma and dendrites carry incoming information. Neurons are most easily identified by their axons in either longitudinal or cross-sectional slide. Groups of neurons are referred to as ganglia in the peripheral nervous system and as nuclei in the central nervous system.
Epithelial tissue is a highly cellular tissue that overlies body surfaces, lines cavities, and forms glands. It is avascular but innervated. Epithelial cells exist in close apposition, forming a barrier between connective tissues and free surfaces. Their surfaces face basally, apically and laterally, with each having distinctive features. Specialized epithelial tissue also exists.
Connective tissue is the most abundant tissue type in the body. It consists of cells, that originate from mesenchyme, and an extracellular matrix. The extracellular matrix is made up of a ground substance and protein fibers. There are several important cell types and three main fibers: collagen, reticular and elastic. Classification of connective tissue into three broad types is based upon the composition of its cellular and extracellular components and its function in the body. 041b061a72