Day 10

Endopeptidases

A type of protease which hydrolyses the peptide bonds between amino acids in the central region of a protein molecule forming a series of peptide molecules - such as trypsin, chymotrypsin and elastase

Exopeptidases

A type of protease which hydrolyses the peptide bonds on the terminal amino acids of the peptide molecules formed by endopeptidases. They progressively release dipeptides and single amino acids - such as carboxypeptidases A and B

Emulsification with Bile, Triglycerides Digested by Pancreatic Lipase, Formation of Micelles, Entry into Enterocyte and Formation of Triglycerides, Chylomicrons enter the Lymphatics

Arrange the 5 main steps in lipid digestion: - Entry into enterocyte and formation of triglycerides - Emulsification with bile - Triglycerides digested by pancreatic lipase - Chylomicrons enter the lymphatics - Formation of micelles

Hepatic, Left Gastric, Splenic

What are the 3 main branches of the celiac artery?

Glucose, Galactose, Fructose

What are the 3 main forms starch is broken into that can enter the enterocyte?

Right and Left Gastroepiploic Arteries

What arteries supply the greater curvature of the stomach?

Storage of Feces Before it is Passed

What is the function of the large intestine?

Digestion and Absorption of Nutrients

What is the function of the small intestine?

Diet and Intestinal Absorption

What is the main source of iron?

Duodenum; Ileum

What part of the small intestine are bile salts secreted into? Where are they reabsorbed?

Liver, Stomach, Spleen, Pancreas, Proximal Descending Duodenum

What structures does the celiac artery supply?

Ferroportin

a membrane Fe transporter - transports Fe out of cells, notably enterocytes and macrophages - transports Fe to plasma

Ferritin

a mobile storage form of Fe - in cells, Fe3+ dissociates from apotransferrin and is used (heme and hemoglobin formation) or it binds to form this - produced in the liver - mostly intracellular

Hepcidin

a peptide hormone produced by hepatocytes - decreases with low body Fe or hypoxia (anemia) - increases with inflammation - binds ferroportin on enterocyte and macrophage membranes and blocks or internalizes ferroportin which decreases iron absorption from intestine, decreased iron supplied to erythroid precursors from macrophages, and increases hemosiderin stores

Glucose; Galactose; Fructose

80% of absorbed monosaccharides is ___________, and the remaining 20% is ________________ and __________

Sodium; Absorption

after digestion, most proteins are in the form of dipeptides, tripeptides, and a few free amino acids - these are then absorbed into the enterocyte by _________ coupled transport - multiple transport proteins then allow systemic ___________ of amino acids

Hemosiderin

an iron-storage protein primarily made in times of iron overload - occurs when there is an increase in hepcidin and therefore decreased iron absorption from intestine - Fe may be taken up by macrophages and stores as this - occurs with inflammation and have decreased ferroportin transfer out of macrophages so it builds up in them - looks like golden brown globules

Micelles; Fat; Bile Salts; Brush Border

as monoglycerides and fatty acids are released from triglycerides they retain their association with bile acids and complex to form _________ - these are composed of a central fat globule with _____________ on the outside - this makes them water soluble and they carry monoglycerides and fatty acids to the _____________ of intestinal cells - have to make these lipids soluble to be allowed to pass into intestinal cells

Hepatic Artery

biggest branch of the celiac artery that supplies the liver and also the lesser curvature of the stomach starting from the pyloric region and also the greater curvature

Luminal

blue

Left Gastric

branch of the celiac artery that supplies part of the lesser curvature of the stomach and last bit of esophagus

Splenic Artery

branch of the celiac artery that supplies the spleen and greater curvature of the stomach

Free Amino Acids

enzymes involved in luminal digestion that break proteins at the end of the polypeptide chain such as carboxypeptidases A and B result in what?

Smaller Peptide Chains

enzymes involves in luminal digestion of proteins that break proteins at internal points such as trypsin, chymotrypsin, elastase result in what?

Steatorrhea

fat in the stool - could be indicative of issues with lipid digestion, lipid absorption, or excess dietary lipids

Apoferritin

ferritin without iron

Emulsification

first step in lipid digestion - the process whereby fat globules are broken into smaller pieces by the detergent action of bile salts (which are released by the gallbladder) - increases the surface for absorption - large aggregates of triglycerides are insoluble in water and need to be broken down physically and held in suspension

Brush Border

intestinal cells have this - contains enzymes that break down di and tri-saccharides into monosaccharides in membraneous phase - also have peptidases that break down peptide products

Cranial Mesenteric

large unpaired visceral branch of the aorta that supplies most of the intestines - caudal part of descending duodenum. ascending duodenum, all of jejunum, ileum, cecum, and ascending, transverse, and part of descending colon

Caudal Mesenteric Artery

large unpaired visceral branch of the aorta that supplies the caudal part of descending colon

Enterocyte; Triglycerides; Chylomicrons; Thoracic

lipids are soluble in the ________ membrane - after entering the enterocyte, the monoglycerides and fatty acids are recombined to form __________ - these are then packaged into _____________ at the golgi apparatus and these enter the lymphatic system and travel to the ____________ duct to be emptied into the bloodstream

Decreased; Increased

low body iron or hypoxia will lead to ___________ hepcidin and therefore _________ iron uptake and availability to combat it

Storage

one of the sites that iron is in the body - such as hemosiderin or ferritin - 25-40%

Other Molecules

one of the sites that iron is in the body - such as in myoglobin, cytochromes, or certain enzymes - <10%

Free Amino Acids

only this form of proteins can be absorbed into the blood - small di or tri peptides are small enough to enter the enterocytes but are broken down to this within the enterocyte

Absorbed

orange

Intracellular

orange

Luminal Phase

protein digestion begins in the stomach with pepsin in this phase - some enzymes break down proteins an internal points along the polypeptide chain while others break proteins at the end of the polypeptide chain

Antimesenteric Ileal Artery

small artery on the ileum that is away from where the mesentery is attached which is where arteries attach to normally - allows you to differentiate the ileum

Small

the daily dietary uptake of iron is a _________ percent of total body iron

Fat Maldigestion/Malabsorption

the following abnormalities could lead to what: - Bile cannot pass into duodenum or isn't formed - Not enough lipase to break down triglycerides into monoglycerides - Brush border enzyme deficiency, damage to villi - Lacteals - abnormality not allowing it to be absorbed

RBC Hemoglobin

the major site for where iron is in the body - recycled - blood loss means iron loss - not something the body wants to lose - 50-70% of iron

Hepatic Portal Veins

the organs are drained by these veins that go to the liver - blood full of nutrients that gets combined with blood from the hepatic artery and filters through sinusoids to get filtered

Luminal Phase

the phase of carbohydrate digestion where the starch breakdown begins by the action of alpha-amylase, which breaks down starch to di and tri-saccharides - products like glucose, galactose and fructose

Toxic; Divide

the reason we may want to decrease body iron is that it can be ________ if present in high amounts - also with inflammation want to sequester iron so invading organisms can't _______ as well

Membraneous Phase

the second phase of chemical digestion of carbohydrate digestion - intestinal cells have a brush border which contains enzymes (lactase, sucrase, maltase) that break down di and tri-saccharides into monosaccharides

Pancreatic Lipase

the second step of lipid digestion involves this enzyme - hydrolyzes each triglyceride molecule into monoglyceride and fatty acid molecules - this is water soluble, so emulsification increases the surface area on which it can act

Micelles

the third step in lipid digestion if the formation of these - because lipids and their breakdown products are not water soluble, they form these allowing them to be absorbed - composed of a central fat globule with molecules of bile salts projecting outwards to cover the surface of it - because of this arrangement these are water soluble - carry monoglyceride and free fatty acids to the brush border of the intestinal cells

Fructose

the transport of this type of carbohydrate is not dependent on sodium co-transportation - instead it is absorbed by a specific transporter (such as facilitated diffusion)

Bile Acids

these are absorbed through sodium dependent absorption in the ileum - re-circulated to liver before storage in the gallbladder

Triglycerides

these are the primary dietary lipids

Bile Salts

these provide the mechanism for emulsification - delivered directly into the duodenum and the majority are reabsorbed into the ileum before being re-circulated to the liver - small fractions may enter the feces or systemic circulation

Young Animals

this age of animals have little or no Fe stores - can develop subclinical or clinical Fe deficiency, especially fast growing pigs - not born with extra iron and not much iron in a milk diet so not until they have enough dietary intake that iron stores can build up -Fe deficiency impairs hemoglobin synthesis and RBC production

Transferrin

this carries Fe3+ to and from tissue - receptors for this are on erythroid precursors, hepatocytes and other cells where this can deliver iron to them - can measure this as part of an iron profile to give us an idea of how much is available to carry iron in the blood

Pepsin

this forms pepsinogen when in an acidic environment which is then released from the chief cells of the stomach

Calcium

this is absorbed through vitamin D dependent absorption in the small intestine

Small Intestine

this organ is where most of the carbohydrate digestion occurs - also where fats and fat soluble vitamins are digested and absorbed

Golgi Apparatus

this organelle produces chylomicrons in the enterocyte

Membraneous Phase

this phase of protein digestion occurs when enzymes such as peptidases in brush border hydrolyze small peptide products of luminal phase protein digestion, yielding free amino acids

Sudan Stain

this stain allows us to see the presence of excess fat globules in the feces

Fat Soluble Vitamins

this type of vitamins are absorbed with micelles

Water Soluble Vitamins

this type of vitamins are co-absorbed with other solutes

Apotransferrin

transferrin without iron

Monosaccharides

ultimately enzymatic digestion of carbohydrates results in these which are small enough to be absorbed from the intestinal wall

Celiac Artery

unpaired visceral branch of the aorta that supplies the organs in the very cranial part of the abdomen - the stomach, liver, spleen, pancreas - also supplies more proximal part of descending duodenum

Sodium Coupled Transport (SGLT1)

uptake of glucose and galactose from lumen into the enterocyte involve transport through this process - sodium moves into the cell down its concentration gradient (maintained by a Na-K-ATPase), and this facilitates the co-absorption of glucose and galactose

Gastroduodenal Artery

what would be the logical name for the artery going from the stomach to the duodenum?

Chylomicrons

in the fifth step of lipid digestion triglycerides are packaged into these - enter the lymphatic system and travel to the thoracic duct to be emptied into the bloodstream

Triglycerides

in the fourth step of lipid digestion once within the enterocyte fatty acids and monoglycerides re-combine to form these

Alpha Amylase

Enzyme in saliva, initiates the chemical breakdown of food - breaks down starch to di and tri-saccharides in luminal phase

GLUT

glucose, galactose, and fructose are then absorbed from the enterocyte and into the blood through this

Membraneous

green

Increased; Decreased

high body iron or inflammation will lead to ___________ hepcidin and therefore _____________ iron uptake and availability