M2: Digestive System Flashcards
What are the major parts of the digestive system?
- Gastrointestinal Tract (GI Tract)
- Accessory Organs
Begins at the oral cavity, passes through the abdominal cavity, and ends at the anus
Gastrointestinal Tract
Pancreas, liver, and gallbladder are under what type of major parts of digestive system
Accessory Organs
True or False
The gastrointestinal tract provides both a location for nutrient digestion and the surface required to absorb those nutrients, it cannot complete the job alone.
True
True or False
Along the length of the tract several accessory organs assist in digestion, including the stomach, large intestine, and small intestine
False: Along the length of the tract several accessory organs assist in digestion, including the pancreas, liver, and gallbladder
What are the 5 process of the GI tract and the accessory organs carry out?
- Ingestion
- Mixing
- Digestion
- Absorption
- Defecation
Foods and liquids are taken into the mouth and eaten.
Ingestion
The smooth muscle in the walls of the GI tract mixes the food and sends it on its way through the tract
Mixing
Food is broken down by both mechanical and chemical processes.
Digestion
The epithelial cells lining the GI tract absorb the digested food molecules and pass them to the blood or lymph
Absorption
Any substance not digested or absorbed, for whatever reason, is passed along to the end of the GI tract, the anus, and leaves the body
Defecation
What are the 4 layers of Gastrointestinal tract
- Mucosa
- Submucosa
- Muscularis
- Serosa
It is the innermost layer, composed of a mucous membrane. This slippery, smooth layer allows ingested food to move along the tract without tearing it.
Mucosa
It is under the mucosa. It includes the glands, nerves, and blood supply for the tract itself
Submucosa
It gives the tract the ability to move substances lengthwise. For most of the tract, the _______ is composed of one layer of longitudinal muscle above another layer of circular muscle.
Muscularis
Outer layer of the GI tract. It is a slippery membrane that permits the tract to move inside the abdominal cavity without aching or causing discomfort.
Serosa
The 4 layers of GI tract work in unison to create the ________ that propels food throughout the tube
Peristaltic wave
Rhythmic muscular contractions of a tube that force contents toward the open end.
Peristaltic wave
True or False
Sometimes food in the stomach does not “agree” with the stomach because it contains bacteria or toxins that irritate the stomach lining. This situation may cause diarrhea.
False: Sometimes food in the stomach does not “agree” with the stomach because it contains bacteria or toxins that irritate the stomach lining. This situation may cause vomiting.
True or False
Although not an easy task from a physiological standpoint, reversing the peristaltic wave and churning the stomach violently while holding the pyloric sphincter closed will expel the stomach contents.
True
True or False
The pyloric sphincter is weaker than the esophageal sphincter and will open first when the stomach contents are under pressure. The entire contents of the stomach then return through the esophagus and the mouth
False: The esophageal sphincter is weaker than the pyloric sphincter and will open first when the stomach contents are under pressure. The entire contents of the stomach then return through the esophagus and the mouth
True or False
The acidity of the stomach is not buffered in the esophagus and mouth, causing some burning as the fluid passes the mucous membranes of these structures
True
True or False
Repeated vomiting can be detrimental to the lining of the mouth as well as the tooth enamel. In addition, replacing the hydrogen ion concentration in the stomach can deplete the hydrogen content of the blood, leading to electrolyte imbalances.
True
What are the three phases Gastric Digestion?
- Cephalic phase
- Gastric phase
- Intestinal phase
In the first phase, thoughts of food and the feel of food in the oral cavity stimulate increased secretion from the gastric pits. The stomach begins to churn more actively in preparation for the incoming food.
Cephalic phase
When the bolus reaches the stomach, the second phase of gastric digestion begins. Here the stomach produces gastrin as well as continuing the production of pepsin and HCl. Gastrin aids in stimulation of the gastric pits, providing a feedback system that speeds digestion. Impulses from the stomach also go back to the brain, maintaining contact with the nervous system
Gastric phase
In the final phase of gastric digestion, the chyme begins to leave through the pyloric sphincter. As the chyme leaves the stomach, gastrin production decreases, the impulses to the brain indicate a lessening of chyme, and the brain begins to slow the stimulation of the gastric pits. At the same time, hormones from the beginning portion of the small intestine initiate activation of the small intestine.
Intestinal phase.
It is where you can find the tongue, salivary glands, and teeth. the lips and cheeks keep food between the teeth during mastication, and buccal glands lining the mouth produce saliva.
Mouth
Maneuvers food for mastication, shapes food into a bolus, maneuvers food for deglutition, detects taste and touch sensations.
Tongue (accessory structure)
Produce saliva, which softens, moistens, and dissolves foods; cleanses mouth and teeth; and initiates the digestion of starch and lipids.
Salivary glands (accessory structure)
Cut, tear, and pulverize food to reduce solids to smaller particles for swallowing.
Teeth (accessory structure)
Receives a bolus from the oral cavity and passes it into the esophagus.
Pharynx
Receives a bolus from the pharynx and moves it into the stomach. This requires relaxation of the upper and then lower esophageal sphincters and secretion of mucus.
Esophagus
Creates mixing waves that macerate food, mix it with secretions of gastric glands (gastric juice), and reduce food to chyme. Gastric juice activates pepsin and kills many microbes in food. Intrinsic factor aids absorption of vitamin B12. The stomach serves as a reservoir for food before releasing it into the small intestine.
Stomach
Secretes juice which buffers acidic gastric juice in chyme (creating the proper pH for digestion in the small intestine), stops the action of pepsin from the stomach, and contains enzymes that digest carbohydrates, proteins, triglycerides, and nucleic acids.
Pancreas. (accessory structure)
Produces bile, needed for emulsification and absorption of lipids in the small intestine; detoxifies blood containing absorbed nutrients and other substances.
Liver (accessory structure)
Stores and concentrates bile and releases it into the small intestine.
Gallbladder (accessory structure)
Creates muscular contractions that mix chyme with digestive juices; migrating motility complexes propel chyme toward the ileocecal sphincter; digestive secretions from the small intestine, pancreas, and liver complete the digestion of carbohydrates, proteins, lipids, and nucleic acids; circular folds, villi, and microvilli increase surface area for absorption; site where nutrients are absorbed.
Small intestine
Create churning, peristalsis, and mass movements that drive the contents of the colon into the rectum; bacteria produce some B vitamins and vitamin K; absorption of water, ions, and vitamins; defecation.
Large intestine
It results from an irritation of the colon.
Diarrhea
It is an open wounds that remain aggravated and painful instead of healing. The mucous lining that normally protects the stomach from digestion must be compromised to develop
Ulcer
What type of ulcer that occur in the stomach
Gastric ulcers
What type of ulcer that occurs in the duodenum of the small intestines
Duodenal ulcers
