Small intestine water

SIWV small intestinal water volume (250mL)... 

SIWV = small intestinal water volume (mL), assumed to be c. 250 mL SITT = small intestinal transit time (min), assumed to be 4.5 h = 270 min. 

Large quantities of water are both secreted into and reabsorbed from the lumen of the small intestine. Water flows across the mucosa in response to osmotic gradients. In the case of secretion, two distinct processes establish an osmotic gradient that pulls water into the lumen of the intestine ... 

In the fasting state, 9 L of fluid enters the proximal small intestine each day. Of this fluid, 2 L are ingested through diet, while the remainder consists of internal secretions. Because of meal content, duodenal chyme is usually hypertonic. When chyme reaches the ileum, the osmolality adjusts to that of plasma, with most dietary fat, carbohydrate, and protein being absorbed. The volume of ileal chyme decreases to about 1 L/day upon entering the colon, which is further reduced by colonic absorption to 100 mL daily. If the small intestine water absorption capacity is exceeded, chyme overloads the colon, resulting in diarrhea. In humans, the colon absorptive capacity is about 5 L daily. Colonic fluid transport is critical to water and electrolyte balance. 

Castor oil is a cathartic only after Hpolysis in the small intestine Hberating ricinoleic acid. Ricinoleic acid inhibits the absorption of water and electrolytes. It is commonly used for preparation of the large bowel for diagnostic procedures. 

Gum arabic. (GA) modifies paracellular water and electrolyte transport in the small intestine. Digestive Diseases and Sciences, Vol. 48, No.4, (April 2003), pp. 755-760, ISSN 0163-2116. 

Their hydroxylated products are more water-soluble than their generally lipophilic substrates, facilitating excretion Liver contains highest amounts, but found In most If not all tissues. Including small Intestine, brain, and lung Located in the smooth endoplasmic reticulum or in mitochondria (steroidogenic hormones)... 

Gas pockets in the intestinal coating and blood in the intestines were observed in five male mice treated with trichloroethylene in drinking water at a dose 660 mg/kg/day (Tucker et al. 1982). Similar effects were observed in five male mice at a dose of 217 mg/kg/day, with no mice affected at a doses of 393 or 18 mg/kg/day. Unfortunately, the number of mice examined for this effect was not clearly stated. Although this effect was not dose-related, it is an interesting observation and appears to be consistent with the human cases of gas-filled cysts in the submucosa of the small intestine observed in persons occupationally exposed to trichloroethylene (Nakajima et al. 1990a) (see Section 2.2.1.2). 

WINGERTZAHN M A, TEICHBERG s, WAPNIR R A (2001) Stimulation of non-sodium-dependent water, electrolyte, and glucose transport in rat small intestine by gum arabic. DigDis Sci. 46 1105-12. 

Hookworm infection is caused by Ancylostoma duodenale or Necator americanus. N. americanus is found in the southeastern United States. Infective larvae enter the host in contaminated food or water or penetrate the skin and migrate to the small intestine. The adult worm attaches to gastrointestinal mucosa and causes injury by lytic destruction of the tissue. Over a period of time, the adult worm can cause anemia and hypopro-teinemia in the host. 

Pectin, the substance that makes jellies and jams so jelly-like, can help lower blood cholesterol levels by forcing the body to make more bile acids. Pectin is a type of fiber, and like most fiber, pectin cannot be digested by the human body. Instead, the fiber moves slowly through the small intestines. When pectin encounters sugar and acid, its molecules trap water within its long chains, turning into a gel-like mass. This gel traps and eventually eliminates bile acids from the gut. When this happens, the body must make more bile acids, reducing the amount of cholesterol in the blood. 

The ability of NB-355 to stimulate locomotor activity and induce dyskinesia in MPTP-treated squirrel monkeys was studied (MPTP induces parkinsonism) [9], NB-355 was similar to L-dopa in stimulating locomotor activity. Furthermore, NB-355 induced less severe dyskinesia than was seen with L-dopa. Some other prodrugs of L-dopa include short-chain alkyl esters (methyl, ethyl, isopropyl, butyl, hydroxypropyl, and hydroxybutyl) intended for rectal absorption [10], These esters of L-dopa have high water solubility (>600 mg/mL). Initial bioavailability studies indicated that all of these esters, with the exception of the hydroxypropyl ester, resulted in significantly greater bioavailability than that obtained with L-dopa itself. However, given the high level of esterase activity in the small intestine, the use of these compounds is limited to rectal administration. 

JR Crison. Estimating the dissolution and absorption of water insoluble drugs in the small intestine. PhD dissertation, The University of Michigan, Ann Arbor, MI, 1993. 

Bile is produced continuously by the liver bile salts are secreted by the hepatocytes and the water, sodium bicarbonate, and other inorganic salts are added by the cells of the bile ducts within the liver. The bile is then transported by way of the common bile duct to the duodenum. Bile facilitates fat digestion and absorption throughout the length of the small intestine. In the terminal region of the ileum, the final segment of the small intestine, the bile salts are actively reabsorbed into the blood, returned to the liver by way of the hepatic portal system, and resecreted into the bile. This recycling of the bile salts from the small intestine back to the liver is referred to as enterohepatic circulation. 

Water and electrolytes. Each day in an average adult, about 5.51 of food and fluids move from the stomach to the small intestine as chyme. An additional 3.5 1 of pancreatic and intestinal secretions produce a total of 9 1 of material in the lumen. Most of this (>7.5 1) is absorbed from the small intestine. The absorption of nutrient molecules, which takes place primarily in the duodenum and jejunum, creates an osmotic gradient for the passive absorption of water. Sodium may be absorbed passively or actively. Passive absorption occurs when the electrochemical gradient favors the movement of Na+ between the absorptive cells through "leaky" tight junctions. Sodium is actively absorbed by way of transporters in the absorptive cell membrane. One type of transporter carries a Na+ ion and a Cl ion into the cell. Another carries a Na+ ion, a K+ ion, and two Cl ions into the cell. 

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