The pylorus is located between the body of the stomach and the duodenum. At the end of the pyloric canal, the circular smooth muscle layer thickens to form the pyloric sphincter. This muscle serves as a valve that controls the rate of stomach emptying and prevents the regurgitation of intestinal contents back into the stomach. Therefore, if the pyloric sphincter is incompetent, intestinal content will flow back into the stomach.
Green, stringy emesis
Thick, brownish, foul-smelling emesis
Bright red, bloody emesis
Clear mucous-looking emesis
The common bile duct and pancreatic duct empty their juices into the duodenum. Bile, a fluid synthesized by the liver that breaks down lipids, and pancreatic juices, which facilitate digestion of lipids, carbohydrates, and proteins, enter the intestine through these ducts. If the GB is removed, a high-lipid meal may not be broken down and digested normally. Neither the stomach size nor the pancreatic duct is removed during GB surgery.
Bile from the GB is needed to breakdown lipids.
Without a GB, the size of the client's stomach has been decreased.
The restaurant may have “bad” grease in their fryer.
When the GB is removed, the pancreatic duct is also removed.
The inner layer is the mucosal layer that produces mucus. This mucus protects and lubricates the inner lining of the GI tract lumen. Secretion of digestive enzymes and substances that break food down, absorption of the breakdown products of digestion, and maintenance of a barrier to prevent the entry of noxious substances and pathogenic organisms also occur in the mucosal layer. Contracting of smooth muscles to propel food forward occurs in the muscularis externa layer. Supporting the abdominal viscera with its connective tissue is the role of the serous layer.
Beginning of the digestive process by secreting enzymes to break food down
Production of mucus to protect and lubricate the inner lining
Contracting of smooth muscles to propel food forward
Supporting the abdominal viscera with its connective tissue
The greater omentum helps to prevent infection from entering the peritoneal cavity and protects the intestines from cold. It often forms adhesions (i.e., bands of fibrous scar tissue) adjacent to inflamed organs such as the appendix, walling off the infection and thereby preventing its spread. The peritoneum is the largest serous membrane and constitutes the outer wall of the intestine, continuous with the mesentery. Haustration is the segmental mixing movements of the large intestine (colon).
The enteric nervous system consists of the intramural neurons (contained in the gastrointestinal tract) of two networks—myenteric and submucosal plexus. The submucosal plexus, which lies between the submucosal and mucosal layers of the wall, is mainly concerned with controlling the function of each segment of the GI tract. It integrates signals received from the mucosal layer into control of motility, intestinal secretions, and absorption of nutrients. The ANS innervates the preganglionic parasympathetic fibers and controls vasovagal reflexes. Sympathetic innervation is mediated by intramural plexus activity.
Stimulation of the parasympathetic nervous system causes a general increase in activity of the entire enteric nervous system. Sympathetic stimulation inhibits activity, causing many effects opposite to those of the parasympathetic system, including enhancement of sphincter function, decreased motility, and increased smooth muscle tone.
Increase in enteric nervous system activity
Decrease in gastrointestinal motility
Enhancement of sphincter function
Increase in smooth muscle tone
The esophageal phase is innervated by the vagus (X) nerve, which initiates the peristaltic waves that will carry the food bolus into the stomach. Gagging is a protective reflex response that can occur during the pharyngeal phase, to prevent food from entering the larynx. Tactile receptors initiate the involuntary part of swallowing during the pharyngeal stage. Hypoglossal (XII) and trigeminal (V) nerves are part of the oral and pharyngeal phases of swallowing. Abducent (VI) is a motor nerve that supplies to the pons and perform function of turning eye laterally.
Gastric contents can empty into the duodenum between antral contractions that block the pylorus. The pH, fatty acid content, and osmolarity of the chyme stimulate cholecystokinin and gastric emptying. Constriction of the pyloric sphincter prevents the backflow of gastric contents and allows them to flow into the duodenum at a rate commensurate with the ability of the duodenum to accept them.
During bile secretion
During opening of the pyloric sphincter
Under gaseous pressure
Inflammatory changes increase motility, which would lead to hyperactive bowel sounds. In many instances, it is not certain whether changes in motility occur because of inflammation or are secondary to the effects of toxins or unabsorbed materials.
Normal bowel sounds
Hyperactive bowel sounds
Absence of bowel sounds
Hypoactive bowel sounds
When the nerve endings in the rectum are stimulated, signals are transmitted first to the sacral cord and then reflexively back to the descending colon, sigmoid colon, rectum, and anus by the pelvic nerves. These impulses greatly increase peristaltic movements as well as relax the internal sphincter, resulting in defecation. Massage, increased fluid intake, and upright positioning are less likely to promote defecation.
Administration of large amounts of free water
Sitting the client in an upright position
Massage of the client's abdomen
Digital stimulation of the client's rectum
Intestinal secretions are mainly water (it contains electrolytes, but the main component is water). Altered secretion or absorption causes fluid volume deficit (dehydration—not hypervolemia), which correlates with hypertonicity (not hypotonicity). Fatigue may be related to loss of volume, but the priority is to restore fluid volume. With lots of secretion loss, the client will likely experience metabolic alkalosis (not acidosis).
Fluid volume deficit
Hypotonic GI motility
Saliva performs three roles: lubrication, antimicrobial protection, and initiation of starch digestion. Saliva contains ptyalin and amylase, which initiate the digestion of dietary starches. The other portions of the GI tract aid in digestion, but all begins in the mouth.
The stomach with its hydrochloric acid production
The duodenum with common bile duct secretions
The mouth with ptyalin and amylase breaking down starches
The jejunum, where peristaltic waves begin
The oxyntic glands are located on the inside surfaces of the body and fundus of the stomach. They secrete HCl and intrinsic factor, which is needed for vitamin B12 absorption.
The gastric mucosa can be easily damaged by drugs such as aspirin, resulting in local ischemia, vascular stasis, hypoxia, and tissue necrosis. Antihypertensives, diuretics, antibiotics, and benzodiazepines do not pose such a significant threat to the integrity of the gastric mucosa.
A client who takes aspirin with each meal to control symptoms of osteoarthritis
A client with a history of anxiety who takes benzodiazepines several times daily
A man whose hypertension requires him to take a diuretic, an ACE inhibitor, and a beta-adrenergic blocker
A client who is taking a broad-spectrum antibiotic to treat a urinary tract infection
An isotonic alkaline fluid is secreted by crypts of Lieberkühn in the intestinal mucosal layer at a high rate, to secrete mucus, electrolytes, and water and to act as a vehicle to aid absorption. Surface enzymes split sugars. Parasympathetic stimulation increases secretion of mucus. Brunner glands secrete large amounts of alkaline mucus to protect the duodenum from acid content.
Vehicle for absorption
Protection from acid content
Enzyme that splits sugars
选择要在Apple App Store上查看的Topgrade应用程序。