By L. Trano. New Saint Andrews College.

Eating too much or too little food can lead to serious medical issues buy 400mg asacol amex, including cardiovascular disease discount asacol 400mg on-line, cancer generic asacol 400 mg amex, anorexia, and diabetes, among others. Combine an unhealthy diet with unhealthy environmental conditions, such as smoking, and the potential medical complications increase significantly. This is different from the calorie (c) used in the physical sciences, which is the amount of heat it takes to raise 1 g of water by 1 °C. The total number of calories needed by one person is dependent on their body mass, age, height, gender, activity level, and the amount of exercise per day. As a rule, people underestimate the number of calories ingested and overestimate the amount they burn through exercise. If an excess of 200 calories per day is ingested, one extra pound of body weight will be gained every 18 days. In fact, the breakdown of carbohydrates requires the least amount of energy, whereas the processing of proteins demands the most energy. In general, the amount of calories ingested and the amount of calories burned determines the overall weight. Calories are in almost everything you ingest, so when considering calorie intake, beverages must also be considered. MyPlate categorizes food into the standard six food groups: fruits, vegetables, grains, protein foods, dairy, and oils. The accompanying website gives clear recommendations regarding quantity and type of each food that you should consume each day, as well as identifying which foods belong in each category. Dairy products are represented by a drink, but the quantity can be applied to other dairy products as well. Department of Agriculture developed food guidelines called MyPlate to help demonstrate how to maintain a healthy lifestyle. It also includes the SuperTracker, a web-based application to help you analyze your own diet and physical activity. In the 1990s, most states reported that less than 10 percent of their populations was obese, and the state with the highest rate reported that only 15 percent of their population was considered obese. Centers for Disease Control and Prevention reported that nearly 36 percent of adults over 20 years old were obese and an additional 33 percent were overweight, leaving only about 30 percent of the population at a healthy weight. Obesity can arise from a number of factors, including overeating, poor diet, sedentary lifestyle, limited sleep, genetic factors, and even diseases or drugs. Severe obesity (morbid obesity) or long-term obesity can result in serious medical conditions, including coronary heart disease; type 2 diabetes; endometrial, breast, or colon cancer; hypertension (high blood pressure); dyslipidemia (high cholesterol or elevated triglycerides); stroke; liver disease; gall bladder disease; sleep apnea or respiratory diseases; osteoarthritis; and infertility. Research has shown that losing weight can help reduce or reverse the complications associated with these conditions. Vitamins Vitamins are organic compounds found in foods and are a necessary part of the biochemical reactions in the body. They are involved in a number of processes, including mineral and bone metabolism, and cell and tissue growth, and they act as cofactors for energy metabolism. You get most of your vitamins through your diet, although some can be formed from the precursors absorbed during digestion. For example, the body synthesizes vitamin A from the β-carotene in orange vegetables like carrots and sweet potatoes. Fat-soluble vitamins A, D, E, and K, are absorbed through the intestinal tract with lipids in chylomicrons. Because they are carried in lipids, fat-soluble vitamins can accumulate in the lipids stored in the body. Water-soluble vitamins, including the eight B vitamins and vitamin C, are absorbed with water in the gastrointestinal tract. These vitamins move easily through bodily fluids, which are water based, so they are not stored in the body. Therefore, hypervitaminosis of water-soluble vitamins rarely occurs, except with an excess of vitamin supplements. Fat-soluble Vitamins Vitamin Recommended and Problems associated with Sources daily Function alternative deficiency allowance name Yellow and orange Eye and fruits and A bone Night blindness, epithelial vegetables, dark retinal or β- 700–900 µg development, changes, immune system green leafy carotene immune deficiency vegetables, eggs, function milk, liver Table 24. The amount of minerals in the body is small—only 4 percent of the total body mass—and most of that consists of the minerals that the body requires in moderate quantities: potassium, sodium, calcium, phosphorus, magnesium, and chloride. The most common minerals in the body are calcium and phosphorous, both of which are stored in the skeleton and necessary for the hardening of bones. Most minerals are ionized, and their ionic forms are used in physiological processes throughout the body. Sodium and chloride ions are electrolytes in the blood and extracellular tissues, and iron ions are critical to the formation of hemoglobin. There are additional trace minerals that are still important to the body’s functions, but their required quantities are much lower. A healthy diet includes most of the minerals your body requires, so supplements and processed foods can add potentially toxic levels of minerals. An organism must ingest a sufficient amount of food to maintain its metabolic rate if the organism is to stay alive for very long.

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The pectinate line (or dentate line) is a horizontal generic asacol 400mg without prescription, jagged band that runs circumferentially just below the level of the anal sinuses purchase 400mg asacol visa, and represents the junction between the hindgut and external skin buy asacol 400 mg with visa. The resulting difference in pain threshold is due to the fact that the upper region is innervated by visceral sensory fibers, and the lower region is innervated by somatic sensory fibers. However, trillions of bacteria live within the large intestine and are referred to as the bacterial flora. Most of the more than 700 species of these bacteria are nonpathogenic commensal organisms that cause no harm as long as they stay in the gut lumen. In fact, many facilitate chemical digestion and absorption, and some synthesize certain vitamins, mainly biotin, pantothenic acid, and vitamin K. First, peptidoglycan, a component of bacterial cell walls, activates the release of chemicals by the mucosa’s epithelial cells, which draft immune cells, especially dendritic cells, into the mucosa. Dendritic cells open the tight junctions between epithelial cells and extend probes into the lumen to evaluate the microbial antigens. The dendritic cells with antigens then travel to neighboring lymphoid follicles in the mucosa where T cells inspect for antigens. This process triggers an IgA-mediated response, if warranted, in the lumen that blocks the commensal organisms from infiltrating the mucosa and setting off a far greater, widespread systematic reaction. Thus, it may not surprise you that the large intestine can be completely removed without significantly affecting digestive functioning. For example, in severe cases of inflammatory bowel disease, the large intestine can be removed by a procedure known as a colectomy. Often, a new fecal pouch can be crafted from the small intestine and sutured to the anus, but if not, an ileostomy can be created by bringing the distal ileum through the abdominal wall, allowing the watery chyme to be collected in a bag-like adhesive appliance. Mechanical Digestion In the large intestine, mechanical digestion begins when chyme moves from the ileum into the cecum, an activity regulated by the ileocecal sphincter. This type of movement involves sluggish segmentation, primarily in the transverse and descending colons. When a haustrum is distended with chyme, its muscle contracts, pushing the residue into the next haustrum. The second type of movement is peristalsis, which, in the large intestine, is slower than in the more proximal portions of the alimentary canal. These strong waves start midway through the transverse colon and quickly force the contents toward the rectum. Mass movements usually occur three or four times per day, either while you eat or immediately afterward. Distension in the stomach and the breakdown products of digestion in the small intestine provoke the gastrocolic reflex, which increases motility, including mass movements, in the colon. Fiber in the diet both softens the stool and increases the power of colonic contractions, optimizing the activities of the colon. Chemical Digestion Although the glands of the large intestine secrete mucus, they do not secrete digestive enzymes. Therefore, chemical digestion in the large intestine occurs exclusively because of bacteria in the lumen of the colon. Through the process of saccharolytic fermentation, bacteria break down some of the remaining carbohydrates. This results in the discharge of hydrogen, carbon dioxide, and methane gases that create flatus (gas) in the colon; flatulence is excessive flatus. More is produced when you eat foods such as beans, which are rich in otherwise indigestible sugars and complex carbohydrates like soluble dietary fiber. Absorption, Feces Formation, and Defecation The small intestine absorbs about 90 percent of the water you ingest (either as liquid or within solid food). The large intestine absorbs most of the remaining water, a process that converts the liquid chyme residue into semisolid feces (“stool”). Of every 500 mL (17 ounces) of food residue that enters the cecum each day, about 150 mL (5 ounces) become feces. You help this process by a voluntary procedure called Valsalva’s maneuver, in which you increase intra-abdominal pressure by contracting your diaphragm and abdominal wall muscles, and closing your glottis. The process of defecation begins when mass movements force feces from the colon into the rectum, stretching the rectal wall and provoking the defecation reflex, which eliminates feces from the rectum. It contracts the sigmoid colon and rectum, relaxes the internal anal sphincter, and initially contracts the external anal sphincter. The presence of feces in the anal canal sends a signal to the brain, which gives you the choice of voluntarily opening the external anal sphincter (defecating) or keeping it temporarily closed. If you decide to delay defecation, it takes a few seconds for the reflex contractions to stop and the rectal walls to relax. If defecation is delayed for an extended time, additional water is absorbed, making the feces firmer and potentially leading to constipation.

Fibroblasts and macrophages are the most common cells in loose connective tissue generic asacol 400mg fast delivery, but mast cells cheap 400 mg asacol mastercard, plasma cells cheap asacol 400 mg with amex, neutrophils and fat cells may also be found. Examine the scanned image at low power, and note that one surface is indented by pits that are lined by columnar epithelial cells. The lymphocytes, which are located within the interstices of this framework, are not well seen in this slide. At higher magnification observe that the intracytoplasmic lipid has been extracted from the fat cells during the histological preparation of the tissue. The thin peripheral ring of cytoplasm and the flattened peripheral nucleus, coupled with the large central vacuole results in the "signet ring" appearance of fat cells. At higher magnification observe the white fat in which each cell contains a single fat droplet (unilocular). Its thick collagenous (type I) bundles stain intensely with eosin and can be seen to course in various directions. Immediately surrounding the lining cells is a very small zone of pale-staining loose areolar connective tissue. Compare the appearance of the collagen bundles (Type I collagen) and fibroblasts with that of the skeletal muscle fibers on the same section. Tendon top, skeletal muscle bottom #11 Bone, rib (H&E) Find the regions of the dense fibrous regularly arranged connective tissue (tendon). Elastic fibers stain reddish-brown to black and form prominent fenestrated, elastic sheets in the aorta. As in other connective tissues, its matrix is composed of fibers (collagenous or elastic) and a ground substance that is rich in extracellular glycosaminoglycans (particularly the chondroitin sulfates). Cartilage is the primary skeletal tissue of the fetus, and it serves as a model for the development of endochondral bone. In the adult, cartilage forms the articular surfaces of joints, the skeleton of the external ear, the septum of the nose, supporting rings and plates of the trachea and bronchi, and intervertebral discs. At higher magnification observe that a perichondrium surrounds the cartilage; this merges with the cartilage on one side and with the surrounding connective tissue of the other side. This is due to the From top to bottom: masking of the collagen fibers by the high concentration of cartilage, pericardium, the glycosaminoglycans in the ground substance. The general organization of this type of cartilage is similar to that of hyaline cartilage, except that elastic fibers predominate over collagen fibers in the matrix. The deposition of inorganic calcium phosphate salts as hydroxyapatite crystals within its matrix is a distinguishing characteristic of bone. In addition, bone functions as a homeostatic reservoir of calcium and phosphate ions and it encloses the hematopoietic elements of the bone marrow. Spongy bone consists of a lattice of branching bony spicules, known as trabeculae, which are surrounded by bone marrow in some regions. Immature (woven) bone (see below in "bone development") is the first bone laid down in prenatal life or in the repair of bone fractures. In this type of bone, the matrix immediately surrounding the osteoblast is called osteoid and is not mineralized. Immature bone is characterized by irregularly arranged, interwoven collagenous fibers within a matrix containing proteoglycans. There are two basic techniques for studying bone with the light microscope, and both of these types of preparations must be studied to appreciate the organic and inorganic components of bone. Haversian Systems (osteons) are distinctive structural units of compact bone that reflect the developmental and nutritive pattern of its lamellar configuration. Haversian systems consist of Haversian canals containing blood vessels and nerves surrounded by concentric lamellae of bone. Lacunae are connected with each other, and ultimately with the perivascular spaces of the Haversian canal, by canaliculi. This communicating system of canaliculi is essential for exchange of gases and metabolites between the osteocytes and the perivascular spaces of the Haversian canal. Note the gradation of the surrounding connective tissue with the periosteum and the increased cellularity of the periosteum. The reversal lines (also known as cementing lines) that delimit the Haversian systems may appear refractile or slightly basophilic. Trabeculae of bone extend into and partially subdivide the marrow cavity, which contains hematopoietic bone marrow. Osteoclasts (multinucleated giant cells with acidophilic cytoplasm, related to the process of bone resorption) may also be seen near the osteochondral junction. Calcifying cartilage and rows of hyaline cartilage cells are present and 20 extend into the cartilage of the proximal end of rib.