EXAM 1 (GI) Flashcards
(103 cards)
WHAT ARE THE FOUR LAYERS OF THE GI WALL
The layers are the mucosa, the submucosa, the muscularis, and the serosa, which is also called the adventitia.
What does the upper esophageal sphincter do
keeps air from entering the esophagus when we breathe
What does the lower esophageal sphincter do
prevents regurgitation of stomach content into the esophagus
T/F: Most nutritional absorption happens in the stomach
False, its just used to digest. Some things that are lipid soluble may be absorbed (alcohol and aspirin)
what are the 3 areas of the stomach
fundus (top), body (middle), and antrum (bottom)
wheres the pyloric sphincter
at end of stomach (antrum). relaxes when food is propelled through the pylorus (gastroduodenal junction)
names the stomach’s 3 layers of smooth muscle
The stomach has three layers of smooth muscle, an outer longitudinal layer, a middle circular layer, and an inner oblique layer, which is the most prominent.
These layers become progressively thicker in the body and antrum of the stomach where food is mixed and then moved into the duodenum.
whats gastrin
hormone that causes gastric glands to secrete hydrochloric acid, pepsinogen, and histamine
what is intrinsic factor
needed to absorb B12, can result in anemia (low RBC, HGB, HCT)
what is gastroferrin
attaches to iron so it can be absorbed through the small intestine.
what is pepsin
chief cells of stomach secrete pepsinogen that is converted to pepsin (enzyme used to break proteins in food down) by the acidity of hydrochloric acid
Once chyme enters the duodenum the pepsin becomes inactive d/t alkaline environment of duodenum
what protects the mucosal layer by stimulating the secretion of mucus and bicarbonate.
Prostaglandins
what is the order of the small intestine
duodenum, jejunum, ileum
what is the peritoneum
It’s the serous membrane that surrounds the organs of the abdomen and the pelvic cavity
The visceral peritoneum lies on the surface of the organs, and the parietal peritoneum lines the wall of the body cavity.
The space between these two layers is called the peritoneal cavity.
whats considered the door from the small intestine to the large intestine
ileocecal valve
What does the small intestine do
Pancreatic and intestinal enzymes, as well as bile salts work to break down carbohydrates and proteins. Fats are also emulsified.
Nutrients are absorbed by active transport, diffusion, and facilitated diffusion. This includes fat and water soluble vitamins, amino acids from protein digestion. Minerals such as sodium, potassium, calcium, magnesium, and iron are absorbed here.
85 to 90% of the water that enters the GI tract is absorbed in the small intestine.
What does the large intestine do
absorbes na, k, acids, and bases
what are the 5 parts of the large intestine
It consists of the cecum, the appendix, the colon, the rectum, and the anal canal.
how does the intestinal microbiome affect our bodies
play a role in the metabolism of bile salts, estrogens, androgens, lipids, carbohydrates, and medications.
The intestinal bacteria produce antimicrobial peptides, hormones, neurotransmitters, anti-inflammatory metabolites, and vitamins. For example, it’s thought that a significant amount of vitamin K is produced by gut bacteria.
what part of the brain regulates vomiting
medulla oblongata
What are two ways the CTZ (chemoreceptor trigger zone) is stimulated to begin vomiting
- signals from stomach/small intestine
- direct action of emetogenic compounds (cancer tx)
name receptors included in the emetic response
Serotonin, glucocorticoids, substance P, neurokinin1, dopamine, acetylcholine, histamine
why use an ssri antagonist
odanestron/zofran emesis control
Block serotonin receptors on vagal afferents and in the chemoreceptor trigger zone (CTZ)
the difference between primary and secondary constipation
Primary condition
Normal transit (functional) – normal rate of stool passage but there is difficulty with stool evacuation
Secondary condition
Caused by many different factors such as diet, medications, various disorders, aging