Gastrointestinal: Part 1 Flashcards
What neurotransmitter is responsible for the relaxation of smooth muscle, CONTRACTION of sphincters, and increased salivary secretion?
Norepinephrine
What neurotransmitter is responsible for contraction of smooth muscle, RELAXATION of sphincters, increased salivary secretion, increased gastric secretion, and increased pancreatic secretion?
Acetylcholine
What substance is responsible for contraction of smooth muscle and DECREASED intestinal secretion and slowing down motility?
Enkephalins
Opioids
Hormones that are released from a neuron in the GI tract and then move out into the blood.
Neurocrines
(Direct Control)
Local diffusion to tissues near the site of release that then bind to the receptor on a target cell.
Paracrine
(Local Control)
What are some examples of Paracrines?
Histamine
Somatostatin
Secreted from gastrointestinal endocrine cells to the portal system (liver), then to systemic blood circulation, and back to cells with receptors for that system.
Hormones
(Distant Control)
What are some examples of hormones involved in Gastrointestinal regulation?
Gastrin
Cholecystokinin
Secretin
What are the 4 major biomolecules that the body recognizes?
Carbohydrates (sugars and starches)
Lipids (fats)
Proteins (amino acids)
Nucleic Acids (DNA and RNA)
Type of carbohydrate that is also known as a simple sugar and cannot be hydrolyzed.
Monosaccharide
What are some examples of Monosaccharides
Glucose
Fructose
Galactose
Two monosaccharides bonded together.
Disaccharides
What are some examples of disaccharides?
Sucrose
Maltose
Lactose
Complex form of carbohydrates that are made up of a chain of monosaccharides.
Polysaccharides
What are some examples of Polysaccharides
Starch
Glycogen
Cellulose (indigestible)
Biomolecule that is used for energy to produced ATP or store in adipose tissue or the liver.
Triglycerides
A type of lipid that is part of our cell membrane and is also used to make steroids like testosterone and estrogens. It can be found in the liver.
Cholesterol
Type of lipid that is a major component of plasma membranes.
Phospholipids
Triglycerides are digested into monoglycerides and free fatty acids via what enzyme?
Gastric Lipase
Phase of digestion that is the “on” switch and responsible for about 30% of initiation of gastrointestinal secretion. Smelling, seeing, and thinking about food begins the process of secretion and motility. (Mouths water and stomach growls)
Cephalic Phase
What are the two enzymes found in saliva?
Salivary Amylase
Lingual Lipase
An enzyme that is secreted by the salivary glands and acts on starches (carbohydrates).
Salivary Amylase
What is starch primarily broken down to via salivary amylase?
Disaccharides
What causes the inactivation of salivary amylase?
Stomach Acid
An enzyme secreted by the sublingual glands under the tongue and acts on triglycerides.
Lingual Lipase
Although Lingual Lipase is made in the mouth, it is inactive. Where does it become active at?
Stomach Acid
(activated in acidic environment of the stomach)
What allows for the digestion of proteins in the stomach?
Hydrochloric Acid
Pepsin
What vitamin is necessary for to make red blood cells via DNA synthesis.
Vitamin B12
What cells excrete intrinsic factor that binds with Vitamin B12 to help it be absorbed to make red blood cells?
Parietal Cells
Cells that are activated by stomach distention and amino acid presence.
G-Cells
What do G-Cells release?
Gastrin
What does gastrin activate?
Enterochromaffin-Like Cells
What do Enterochromaffin like cells release and do?
Histamine
Increase Motility
What does histamine do in the gastrointestinal system?
Activates Parietal Cells by binding to H2 receptors.
What is released by the activation of parietal cells?
Hydrochloric Acid
Intrinsic Factor
What does Hydrochloric Acid activate?
Chief Cells
What do Chief cells release?
Pepsinogen
Gastric Lipase
What does pepsinogen become when activated by stomach acid?
Pepsin
Histamine H2 receptor antagonists block histamine biding in the stomach causing what?
Reduced Acid Production
What does Pepsin do?
Digest Proteins
Why is it that the inactive form of pepsin (pepsinogen) is released in the inactive state?
Protect the cells that produce it from being broken down
More acid being pumped into the stomach results in the body pumping more bicarbonate into the blood. (What is this called)
Alkaline Tide
Protective proteins that inhibit hydrochloric acid production via inhibition of Extrachromaffin-Like cells.
Prostaglandins
What happens if you take NSAIDs?
Increased Hydrochloric Acid production
Peptide hormone that is secreted from D-Cells in the stomach and is triggered by a low stomach pH.
Somatostatin
What effect does somatostatin have on gastric acid secretion.
Inhibits gastric acid secretion
What hormones are released when chyme moves into the duodenum?
Secretin and Cholecystokinin
Hormone that is activated by a low pH from the stomach and secreted from S-Cells in the duodenum.
Secretin
What does Secretin cause the releases of?
Bicarbonate from the Pancreas
What hormone is activated by the presence of fats and amino acids?
Cholecystokinin
Hormone that stimulates the release of enzymes from the Pancreas and release of bile by liver and gall bladder, and a feeling of being full.
Cholecystokinin
Buffering capacity of the duodenum may be overwhelmed with excess H+ production from the stomach resulting in what?
Duodenal Ulcers
What digestion takes place in the small intestine?
All of it
- Proteins
- Lipids
- Carbohydrates
- Nucleic Acids
What does trypsin, chymotrypsin, and carboxypeptidase allow the digestion of?
Proteins
What does pancreatic amylase allow the digestion of?
Carbohydrates
What do lipases allow the digestion of?
Lipids
Deoxyribonucleases and ribonucleases allow for the digestion of what?
Nucleic Acids
Segmental contractions mix back and forth, separating the chyme for better mixing and digestion.
Peristalsis
Where does most digestion and absorption of fluid take place?
Small Intestine
