Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

25 Cards in this Set

  • Front
  • Back
What are the 4 parts of the digestive system?
1. upper part - mouth, esophagus, and stomach (acts as a receptable for food and where initial digestion takes place) 2. middle part - small intestine (where most digestive and absorptive process occur) 3. lower part - cecum, colon, and rectub (storage channel for waster eliminatio) 4. accessory organs - salivary glands, liver, and pancreas
Describe how the musclular wall of the esophagus changes, proximal to distally
- the upper third of the esophagus are skeletak-type striated muscle - these muscle fibers are gradually replaced by smooth muscle fibers - the lower third of the esophagus is entirely smooth muscle
What is the cardiac orifice?
the opening through which the esophagus opens into the stomach
What portion of the small intestine digests and absorbs food?
jejunum and ileum
What are the 5 layers of the digestive tract?
1. mucosal layer - produces mucus that lubricates and protects the inner surface 2. submucosal layer - connective tissue that contains blood vessels, nerves, and structures that secrete digestive enzymes 3. circular muscle layer 4. longitudinal muscle layer 5. outer serous layer - forms the peritoneum and is continuous with the mesentery
What is the function of the mesentery?
- a double-layered fold of peritoneum that suspends the jejunum and ileum - contains blood vessels nerves and lympatic vessels that supply the intestinal wall
What are some characteristics of the greater omentum?
- a filmy double fold of peritoneal membrane that extends from the stomach to cover the transverse colon and folds of the intestine - controls the spread of infection from GI contents by adhering to the inflamed area so that infection is less likely to enter the peritonenal cavity
What are the 2 nervous systems that control GI function?
1. Enteric nervous system - lies entirely within the wall of the GI tract; consists of the myenteric and submucosal plexus 2. autonomic nervous system - parasympathetic and sympathetic
What is the function of the vagus nerve in the GI tract?
- provides efferent parasympathetic innervation to the stomach,m small intestine, cecum, ascending colon, and transverse colon - increased vagal activity enhanced gastric motility
What are some characterisitics of sympathetic innervation of the GI tract?
- occurs through the thoracic chain of sympathetic ganglia - sympathetic stimulation inhibits gastric motility
What are the 3 phases of swallowing?
1. oral (or voluntary) phase 2. pharyngeal phase 3. esophageal phase
Name 3 hormones produced by the GI tract
1. gastrin - stimulates secretion of gastric acid and pepsinogen 2. secretin - stimulates secretion of bicarbonate-containing soution by pancreas and liver 3. cholecystokinin - stimulates contraction of the gall bladder; stimualtes secretion of pancreatic enzumes; slows gastric emptying
What is the function of histamine in the GI tract?
- histamine is released in response to gastrin and stimulates gastric acid secretion by the parietal cells
What glands secrete saliva?
parotid, submaxillary, sublingual, and buccal glands
What are the 3 functions of saliva?
1. protection and lubrication - protects the oral mucosa and coats the food 2. protective antibicrobial action - cleans the mouth and contains the enzyme lysozyme 3. initiate the digestion of dietary starches - contains ptayalin and amylase
What are the 2 types of glands in the stomach mucosa?
1. oxyntic (or gastric) glands - located in the proximal 80% of the stomach; secrete HCl, pepsinogen, intrinsic factor, and mucus 2. pyloric glands - located in the distal 20% of the stomach; secretes mainly mucus, some pepsinogen, and gastrin
What is the function of intrinsic factor?
necessary for the absorption of vitamin B12
What are Brunner's glands?
- mucus-producing glands located at the site where stomach contents enter the duodenum - produces alkaline mucus which protects the duodenum from the acid content in gastric chyme
What is the difference between digestion and absorption?
- digestion is the breakdown of foods into their constituent parts; requires hydrolysis, enzyme cleavage, and fat emulsification - absoprtion is the procces of moving nutrients and other materials from the external environment of the GI tract into the internal environment
Describe how characteristic of the small intestine help in absorbtion
- the small intestine has a large surface area due to circular folds and finger-like projections called villi - each villi has an artery and vein (which bring blood to the surface and receive nutrients) and a lymph vessel (or lacteal) that absorbs fat
What are enterocytes?
- the cells that cover each villus - contribute to the absorptive and difestive functions of the small bowel - secrete brush border enzymes that aid in the digestion of carbohydrates and proteins
How are carbohydrates digested and absorbed?
- first they are broken down into monosaccride by various enzymes (ie. lactase, sucrase, amylase, maltase, alpha-dextrimase) - some carhbohydrates are absorbed by facilitated diffusion (fructose) - others require ATP (glucose and galactose)
Describe how fats are absorbed
- fats (or triglycerides) are broken down by gastric and pancreatic lipase - Bile salts carry the fatty acids and fat soluble vitamins to the intestinal villi, by forming micelles, where they are absorbed
What is steatorrhea?
- fatty stool - occurs when fat is not absorbed in the intestine and is excreted in the stool
What enzymes breakdown proteins?
- pepsin (precursor is pepsinogen) begins digestion in the stomach - trypsin (precursor trypsinohen), and chymotrypsin, carboxypeptidase, andelastase continues digestion in the duodenum