Ch 21 Flashcards
This branch of the nervous system is housed completely in the GI region
Enteric
This term gastro refers to this structure
Stomach
The chemical and mechanical breakdown of food into absorbable units is called
Digestion
The general term for movement of material in the gastrointestinal tract caused by smooth muscle contraction is
Motility
Movement of substances from cells into the gastrointestinal tract is called
Secretion
Movement of substances from the gastrointestinal tract into the extracellular fluid is called
Absorption
This type of smooth muscle activity occurs in order to help mix the contents in the GI tract
Segmentation
Or segmental contraction
These structures in the mucosa of the GI tract are part of the gut associated lymphoid tissue (Galt) which contain immune system cells to protect from pathogens
Peyers patches
The substance made up of the ingested food and secretions from the stomach is called
Chyme
The mass of food that is moved along the GI tract is called a
Bolus
Progressive waves of contractions that move through sections of the GI tract are called
Peristalsis
To swallow
Deglutition
To chew
Mastication.
To take in food or drink is called
Ingestion
Removal of material from the body
Elimination
This phase of digestion occurs from stimulus such as sight smell taste of food and initiates food forward response
Cephalic phase
This phase of digestion is when food enters stomach and initiates short reflexes
Gastric phase
This phase of digestion is when chime enters the small intestines and chemical digestion starts
Intestinal phase
These cells secrete enzymes into the stomach
Chief cells
The pH of the gastric juice is approximately
2
A proton pump inhibitor would act on transporters and these cells of the stomach
Parietall cells
This enzyme breaks peptide bonds
Pepsin
These gastric cells secrete hydrochloric acid into the lumen of the stomach
Parietall cells
These cells use histamine as a paracrine In the gastric lining
Ecl cells
These cells secrete mucus and bicarbonate into the stomach
Mucous neck cells
Secretions from these cells play a critical role in negative feedback loop that regulate the secretion of acid into the stomach
D cells
That is packaged with cholesterol and protein to form this absorbable substance
Chylomicron
This enzyme breaks the bonds holding fatty acids to glycerol
Lipase
This enzyme breaks the bonds holding fatty acids to glycerol
Lipase
This secretion contains salts that can help break apart large fat globs into droplets
Bile
This substance is secreted by cells of the duodenum and pancreas to neutralize the pH of the chime entering from the stomach
Bicarbonate
The category of brush border enzymes that digest sucrose lactose and maltose are collectively called
Disaccharidases
This category of enzymes breaks internal bonds in a peptide chain
Endopeptidase
This enzyme activates pancreatic zymogens in small intestines
Trypsin
A pancreatic enzyme that is secreted in its inactive form is called a
Zymogen
Aminopeptidase and carboxypeptidase fall into this category of enzymes
Exopeptidase
Break off outside of chain
Absorbed fat enters the _____
Lymph
During absorption this transporter moves fructose across the luminal membrane of the intestinal mucosa cell
GLUT5
This transporter moves monosaccharides across the basilateral membrane of the intestinal mucosa cell
GLUT2
Transport of glucose and galactose across the luminal membrane relies on the activity of this transporter on the basolateral membrane
Sodium potassium pump
Name the types of polysaccharides that can be digested
Starch and glucogen
Name the enzymes that can digest the polysaccharides and identify where they are active in the GI tract
Salivary amylase (mouth)
Pancreatic amylase (small intestine)
Name the three disaccharides that can be digested and the enzymes that can digest each
Disaccharides:. Enzyme:
1) maltose 1) maltase
2) sucrose. 2) sucrase
3) lactose. 3) lactase
Where exactly are disaccharidases located
Maltase, sucrase, and lactase
Brush border of small intestines
Name the three monosaccharides that can be absorbed
1) Glucose
2) fructose
3) galactose
Which specific fluid compartment do the monosaccharides enter upon absorption
Apical/luminal membrane
Where are most of the monosaccharides delivered following absorption
Into cells of the small intestine
Glucose is transported OUT of the lumen of the GI tract with this substance (co-transport)
Sodium glucose transporter
SGLT
This transporter is used to move galactose OUT of the lumen of the GI tract
Sodium glucose transporter
SGLT
Fructose is moved out of the lumen of the GI tract by this type of transporter
GLUT5
Glucose or galactose are moved out of the lumen of the GI tract by this TYPE of transport ( based on energy requirements)
Simple diffusion
The GLUT2 transporter moves these monosaccharides into the extracellular fluid
Glucose galactose and fructose
Glucose and galactose are moved INTO the extra cellular fluid by this process ( based on energy requirements)
Secondary active transport
Where is secondary active transport of glucose and galactose taking place in the GI tract
Small intestines
What molecules act on fat to break it into smaller droplets (fig 21.16)
Bile salt
What is the process of making small fat droplets called (21.16)
Emulsification
What is a complex form of a lipid molecule called
Triglyceride
What are the enzymes that can act on triglycerides (2)
Pancreatic lipase
Colipase
What is a triglyceride molecule broken down into in the GI tract
1 monoglyceride
+
2 fatty acids
Where in the GI tract is the breakdown of triglycerides happening
Cell of the small intestine
What is the source of bile (where is it made)
The liver
The fatty acids and glyceride molecules enter the cells in the walls of the GI tract and are reassembled into what molecule
Back to a triglyceride
After triglyceride is reassembled in the GI tract it comes together with these two molecules
Protein
Cholesterol
When triglyceride comes together with protein and cholesterol they form a complex called a _____ which enters the length
Chylomicron
This type of enzyme breaks peptide bonds at the ends of the peptide
Exopeptidase
This type of enzymes breaks internal peptide bonds in a peptide
Endopeptidase
The name of the enzyme that breaks peptide bonds at the amine end of the peptide chain is
Amino peptidase
The name of the enzyme that breaks peptide bonds at the carboxyl end of the peptide chain is
Carboxypeptidase
Name the enzymes that break internal peptide bonds (3 endopeptidase)
1) pepsin
2) chymotrypsin
3) Trypsin
Name the brush border proteases
Aminopeptidase
Name the pancreatic proteases
Carboxypeptidase
These peptides are transported out of the lumen of the GI tract with hydrogen (2)
Dipeptides
Tripeptides
Based on energy requirements what type of transport is involved in the exchange of sodium and hydrogen on the luminal membrane (fig 21.18)
Secondary active transport
Small peptides are transported across the cell by this process
This transport is actually made up of two processes in one
One on luminal membrane and the other on the basilateral membrane name them in order
1) endocytosis (luminal)
2) exocytosis (basolateral)
=
Transcytosis
Amino acids and sodium are transported across the basilateral membrane by this process based only on the number of substances being moved
Co transport
Amino acids and sodium are transported across the luminal membrane by this process
(Based only on the number and direction of substances being moved)
Symport
Amino acids and small peptides / proteins are absorbed into this fluid compartment
Hepatic portal vein
Where will most of the amino acids and peptides be delivered in the body
Liver
In the stomach gastrin somatostatin and histamine act as this type of signal molecule
Neurohormone
When released this hormone slows digestion by inhibiting gastric emptying and hydrogen secretion
Cholecystokinin
The stimulus for the release of the hormone cholecystokinin is
Fatty acid and amino acid
The action of cholecystokinin hormone includes feeling full the technical term for feeling full is
Satiety
What are two hormones that promote feeling full
Cholecystokinin
GLP 1
Salivary amylase found in the mouth targets what biomolecule class
Carbohydrates
Salivary lipase found in the mouth targets digestion of what biomolecule class
Lipids and fat ( minimal)
Does the esophagus contribute to digestion
No
Does digestion take place in the esophagus
Yes
salivary amylases continues working on digestion
What secretions are found in the stomach
Gastric juices:
Hydrochloride pepsinogen gastric lipase mucus bicarbonate and other substances
What biomolecule class does the stomach predominantly digest
Protein
Tertiary breakdown to peptide bond chains
Where in the body does most digestion/absorption take place
Small intestines
What secretions are found in the small intestines
Bile pancreatic juice enzymes bicarbonate pancreatic amylase
What biomolecule class does the small intestines digest
Proteins (broken down to peptide bonds)
Carbs
Fat (main site for digestion)
In this intestinal reflex there is increased gastric activity and increased ilium motility
Gastroileal reflex
In this intestinal reflex there is ilium distention and decreased gastric motility
Ileogastric reflex
In this intestinal reflex there is extreme distention of one segment and increased relaxation of other segments
Intestino - intestinal reflexes
These fatty acid complexes migrate to brush border membranes (phospholipids, fatty acids, cholesterol, monoglycerides, diglycerides fatty acids)
Micelles
Hydrogen is a proton this class of drugs inactivates them
Proton pump inhibitor
Prilosec nexium protonix
Do we break down food molecules into individual atoms
No
Food starts: (protein carbs lipids)
We break down to:
(Amino acids, monosaccharides, glycerol, fatty acids, nucleotides)
