Structure and Physiology

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For descriptive purposes, the abdominal cavity is usually divided visually into four quadrants. Two imaginary perpendicular lines cross at the umbilicus to divide the abdomen into the right upper and right lower quadrants and the left upper and left lower quadrants. One line extends from the sternum to the pubic bone through the umbilicus. The second line is at right angles to the first at the level of the umbilicus. The four quadrants formed and the abdominal organs within each quadrant are shown in Figure 17-1.

Another method of description divides the abdomen into nine areas: epigastric, umbilical, suprapubic, right and left hypochondrium, right and left lumbar, and right and left inguinal. Two imaginary lines are drawn by extending the midclavicular lines to the middle of the inguinal ligaments. These lines form the lateral extent of the rectus abdominis muscles. At right angles to these lines, two parallel lines are drawn: one at the costal margins and the other at the anterosuperior iliac spines. The nine-area system is shown in Figure 17-2.

The examiner should recognize the abdominal structures that are located in each area. Table 17-1 lists the organs present in each of the four quadrants.

Because the kidneys, duodenum, and pancreas are posterior organs, it is unlikely that abnormalities in these organs can be palpated in adults. In children, in whom the abdominal muscles are less developed, renal masses, especially on the right side, can often be palpated.

A detailed description of the pathophysiology of the gastrointestinal system is beyond the scope of this text. A brief statement regarding the basic physiology serves to integrate the signs and symptoms of abdominal disease.

As food passes into the esophagus, an obstructing lesion can produce dysphagia, or difficulty swallowing. Gastroesophageal reflux can lead to heartburn. Upon entry of partially digested food into the stomach, the stomach relaxes. A failure of this relaxation may lead to early satiety or pain. The stomach functions as a food reservoir, secreting gastric juice and providing peristaltic activity with its muscular wall. Between 2 and 3 L of gastric juice is produced daily by the stomach lining and affects the digestion of proteins. The semifluid, creamy material produced by gastric digestion of food is called chyme. Secretion of gastric juice may produce pain if a gastric ulcer is present. Intermittent emptying of the stomach occurs when intragastric pressure overcomes the resistance of the pyloric sphincter. Emptying is normally complete within 6 hours after eating. Any obstruction to gastric emptying may produce vomiting.

Stomach Quadrants

Figure 17-1 The four abdominal quadrants.

Suprapubic Area

Figure 17-2 The nine abdominal areas.

Figure 17-1 The four abdominal quadrants.

Figure 17-2 The nine abdominal areas.

Table 17-1. Abdominal Structures by Quadrants Right Left

Upper Quadrant

Liver

Liver, left lobe

Gallbladder

Spleen

Pylorus

Stomach

Duodenum

Pancreas: body

Pancreas: head

Left adrenal gland

Right adrenal gland

Left kidney: upper pole

Right kidney: upper pole

Splenic flexure

Hepatic flexure

Transverse colon: portion

Ascending colon: portion

Descending colon: portion

Transverse colon: portion

Lower Quadrant

Right kidney: lower pole

Left kidney: lower pole

Cecum

Sigmoid colon

Appendix

Descending colon: portion

Ascending colon: portion

Left ovary

Right ovary

Left fallopian tube

Right fallopian tube

Left ureter

Right ureter

Left spermatic cord

Right spermatic cord

Uterus (if enlarged)

Uterus (if enlarged)

Bladder (if enlarged)

Bladder (if enlarged)

The entry of chyme from the stomach into the duodenum stimulates the secretion of pancreatic enzymes and contraction of the gallbladder. The flow of pancreatic juice is maximal approximately 2 hours after a meal;the daily output is 1 to 2 L. The three enzymes of chyme—lipase, amylase, and trypsin—are responsible for the digestion of fats, starches, and proteins, respectively. In cases of pancreatic insufficiency, the stool is pale and bulky and has an odor that is more offensive than normal. The chyme and the neutralizing effect of these enzymes reduce the acidity of the duodenal contents and relieve the pain of peptic duodenal ulcer. The pain from an acutely inflamed gallbladder or from pancreatitis worsens at this phase of the digestive cycle.

The digested food continues its course through the small intestine, in which further digestion and absorption occur. Failure of bile production or its release from the gallbladder results in decreased digestion and absorption of fats, leading to diarrhea. Gallstones may form as a result of diet or hereditary predisposition.

The liver produces bile, detoxifies the byproducts of the digestion of food, and metabolizes proteins, lipids, and carbohydrates. The daily output of bile is about 1 L. In the absence of normal liver function, jaundice, ascites, and coma may result.

The jejunum and ileum further digest and absorb the nutrients. Bile acids and vitamin B12 are absorbed in the ileum. The dark color of stool is caused by the presence of stercobilin, a metabolite of bilirubin, that is secreted in the bile. If bile does not flow into the small intestine, the stools become pale brown to gray and are called acholic, or free from bile.

The colon functions to remove much of the remaining water and electrolytes from the chyme. Approximately 600 mL of fluid enters the colon daily, and only 200 mL of water is excreted in the stool daily. Abnormal colonic function leads to diarrhea or constipation. Aneurysmal pouches of colonic mucosa may cause bleeding;if they are infected, pain results. Colonic obstruction produces severe pain. Tumors may cause obstruction or bleeding.

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Herbal Remedies For Acid Reflux

Herbal Remedies For Acid Reflux

Gastroesophageal reflux disease is the medical term for what we know as acid reflux. Acid reflux occurs when the stomach releases its liquid back into the esophagus, causing inflammation and damage to the esophageal lining. The regurgitated acid most often consists of a few compoundsbr acid, bile, and pepsin.

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