GASTROINTESTINAL SYSTEM
The order of the small intestine segments, from proximal to distal, is
D,J,I Duodenum, Jejunum, and Ileum
What does salivary amylase do?
breaks down carbohydrates in food.
pepsinogen
combines with HCl in the stomach to form pepsin
gastric lipase
digests fats
ascending colon
first part of the large intestine that travels upward from the cecum to the undersurface of the liver.
Duodenum
first part of the small intestine.
Main function of the small intestine
most of the absorption of nutrients happens at this level
function of the pancreas releasing bicarbonate ions
neutralize acidic chymeand create an alkaline environment. The digestive enzymes work better in an alkaline environment
3 sets of salivary glans
parotid, sublingual and submandibular glands. These glands secrete mucous and the digestive enzyme- salivary amylase.
Secretions of the stomach
pepsinogen intrinsic factor hydrochloric acid gastric lipase
descending colon
portion of the colon that extends downward from the transverse colon down toward the rectum
intrinsic factor
promotes vitamin B12 absorption
pyloric sphincter
ring of muscle that guards the opening between the stomach and the duodenum (small intestine)
What hormone does the duodenum secrete that promotes pancreatic secretions?
secretin (SECRETIN to help SECRETE pancreatic fluids)
enzyme
substance that chemically breaks down food.
deglutition
the act of swallowing
what region does food enter the stomach at?
the cardiac region
Bolus
A term used to describe food after it has been chewed and mixed with saliva
What enzymes does the pancreas release
trypsin chymotrypsin pancreatic lipase pancreatic amylase Bicarbonate ions
epiglottis
A flap of tissue that seals off the windpipe and prevents food from entering.
Rectum
A short tube at the end of the large intestine where waste material is compressed into a solid form before being eliminated
Pancreas
An organs in the abdominal cavity with two roles. The first is an exocrine role: to produce digestive enzymes and bicarbonate, which are delivered to the small intestine (duodenum) via the pancreatic duct. The second is an endocrine role: to secrete insulin and glucagon into the bloodstream to help regulate blood glucose levels.
Peristalsis
Involuntary waves of muscle contraction that keep food moving along in one direction through the digestive system.
Jejunum
Middle portion of the small intestine. Primary function is to absorb sugars, amino acids, and fatty acids.
How are the enzymes from the pancreas released into the duodenum?
The pancreatic duct
esophageal sphincter
a sphincter muscle at the upper or lower end of the esophagus. Prevents reflux of food back into the esophagus.
sigmoid colon
an S-shaped structure that continues from the descending colon above and joins with the rectum below
regions of the stomach
cardia, fundus, body, pylorus Rugae is inside the stomach that along with digestive substances will turn the bolus of food into chyme.
Stomach
large muscular sac that continues the mechanical and chemical digestion of food
ileum
last part of small intestine. Absorbs any remaining nutrients that did not get absorbed by the duodenum or the jejunum. In particular, it absorbs vitamin b12 as well as bile acids so they can get recycled.
Enzymes of the small intestine
lipases (fat digestion) Proteases (protein digestion) Maltase, Lactase and sucrase (carbohydrate and simple sugar digestion)
Bile is produced by the _________ and stored in the ____________.
liver, gallbladder.
main function of large intestine
small amount of nutrient absorption but the large amount of water and electrolytes is absorbed. Also bacteria is broken down
transverse colon
the middle part of the large intestine, passing across the abdomen from right to left below the stomach.
defecation reflex is triggered by
the parasympathetic nervous system
What system controls the release of gastrin?
the parasympathetic nervous system Gastrin controls the release of substances that aid in chemical digestion.
deglutition
the transport if the bolus from the mouth to the stomach
CCK (cholecystokinin)
when fatty chyme enters the duodenum, the hormone cholecystokinin is secreted by the duodenum. CCK tells the gallbladder ti contract and the bile stored in it to travel through the common bile duct and into the duodenum. Bile emulsifies fats to help with enzyme digestion.