Ch 14: Digestive System Flashcards
What is the GI tract flow?
Mouth
Esophagus
Stomach
Small Intestine (Duodenum > Jejunum > Ileum)
Large Intestine [Colon] (Cecum > Transverse colon > Descending colon > Sigmoid colon)
Rectum
Anus
What is the GI tract?
Long tube that’s open at both ends for the transit of food during processing
What are accessories?
Salivary glands
Liver
Gallbladder
Pancreas
What are the 4 digestive system functions?
Ingestion
Digestion
Absorption
Defecation
What is ingestion?
Taking in food
What is digestion?
Breaking food into nutrient molecules
What is absorption?
Movement of nutrients into the blood stream
What is defacation?
Excrete to rid the body of indigestible waste
What are the 4 layers of the GI tract from inner most to outer most?
Mucosa
Submucosa
Muscularis externa
Serosa
What is the peritoneum?
Serous membranes of abdominal cavity
What are the 3 peritonea?
Visceral peritoneum
Parietal peritoneum
Peritoneal cavity
Which peritoneum is this:
External surface of most digestive organs
Visceral peritoneum
Which peritoneum is this:
Lines body wall
Parietal peritoneum
What is the peritoneal cavity?
Fluid filled space between the 2 peritonea
What is the name of the double layer of peritoneum?
Mesentery
What does the mesentery do?
- Extends from body wall to digestive organs
- Routes for blood vessels, lymphatics, and nerves
- Holds organs in place
- Stores fat
What is this:
- Collapsible, muscular tube
- Posterior to the trachea
- Passes through diaphragm to join stomach
- Gastroesophageal sphincter
Esophagus
What does the Gastroesophageal sphincter do?
Prevents regurgitation of food from stomach
How many layers of smooth muscle does the stomach have?
3
Longitudinal, Circular, Oblique
What does the rugae do?
Expands to accommodate for food
What are these the functions of?
- Mixes saliva, food, and gastric juice to form chyme
- Secretes gastric juice: HCl, Pepsin, Intrinsic factor, Gastric lipase
- Reservoir for food before release into small intestine
- Secretes gastrin into the blood
Stomach
What is intrinsic factor required for?
Absorption of vitamin B12
What is the main hormone that regulates acid secretion in stomach?
Gastrin
What is the 1st layer of the stomach barrier?
Thick layer of bicarbonate - rich mucus
What is the 2nd layer of the stomach barrier?
Tight junctions between epithelial cells
(prevent juice seeping underneath tissue)
What is the 3rd layer of the stomach barrier?
Damaged epithelial cells are quickly replaced by division of stem cells
(surface cells are replaced every 3-6 days)
What is gastrin activated by?
Vagus nerve
Gastrin related peptide
Peptides in stomach lumen
How is gastrin produced?
Released into blood until it reaches parietal cells
The small intestine is from what to what?
Pyloric sphincter to ileocecal valve