GI - 15

Question 1

The Pancreas

Answer 1

-label slide 4
-hepatopancreatic ampulla = pancreatic secretions enter duodenum

Question 2

Pancreas Blood Supply

Answer 2

-label slide 5

Question 3

Pancreas Exocrine

Answer 3

-exocrine (pancrease enzymes) secreted to duodenum via hepatopancreatic ampulla
-acinar cells secrete biacarb juice from pancreas
-exocrine secretions travel through ducts, endocrine through bloodstream

Question 4

Pancreas Secretions

Answer 4

-pancreatic amylase (starch)
-pancreatic lipase (fats)
-pancreatic proteases (protein):
trypsin/ogen, chymotrypsin/ogen, pro/carboxypeptidase, pro/elastase

all inactive enzymes, all activated by trypsin (which is activated by brush border enzyme enterokinase) - protective measure

Question 5

Components of the Liver

Answer 5

-label slides 11-14
-right lobe, falciform ligament, left lobe, round ligament, caudate lobe, quadrate lobe, vena cava and gallbladder, porta hepatis (vacular door to liver)

Question 6

Liver Ducts

Answer 6

right hepatic duct, left hepatic duct, common heatic duct, common bile duct, hepatopancreatic duct
-chart on slide 14

Question 7

Liver’s Dual Blood Supply

Answer 7

-slide 15

-hepatic vein (oxygen and nutrient poor, away from liver)

-hepatic artery (from celiac trunk, oxygen rich to liver)

-hepatic portal vein (oxygen poor, nutrient rich to liver)

Question 8

Hepatocytes

Answer 8

-synthesis
-storage
-detoxification
-metabolism
-clean blood and blood cells
-liver lobule = hexagonal shape that hepatocytes are organized into
-sinusoid is like blood vessel with lots of holes
-kupffer cells
-has a portal triad (vessels at corner of lobules; bile duct, branch of hepatic portal vein, branch of hepatic artery)

Question 9

Functions of Liver

Answer 9

-produces bile
-excretion of bilirubin, cholesterol, hormones, drugs
-processing of fats, proteins and carbohydrates
-storage of glycogen, vitamins, minerals
-synthesis of serum proteinss –> albumin and clotting factors

Question 10

Carbohydrate Processing

Answer 10

-glucose stored as glycogen –> glycemic regulation
-liver stores 1-2 days worth of glucose (only source of energy for NS)
-can convert glucose into triglycerides
-gluconeogensis = AA’s + glycerol + lactate

Question 11

Amino Acid Processing

Answer 11

-amino acids kept for protein synthesis
-converts toxic ammonia (byproduct of AA breakdown to make ATP) to urea
-amino acid has amino group (NH3), r group and carboxyl group (COO)

Question 12

Synthesis of Serum Proteins

Answer 12

-albumin: colloid osmotic pressure, transports lipid-soluble hormones/drugs
-coagulation factors
-complete proteins - immune support

Question 13

Bile Production

Answer 13

-1L produced daily by the hepatocytes
-used immediately and stored in the gallbladder
-water, cholesterol, bile salts (Na + K), bilirubin (pigment)
-aids in digestion of fats –> cholesterol metabolism, excretion of lipid-soluble drugs

Question 14

Lipid Processing

Answer 14

-lipoproteins = packages that can be transported to and from tissues
-have to travel through blood
-chylo = processed by adipocyte
-VLDL = hepatocyte to adipocyte
-LDL (bad cholesterol) = hepatocyte to tissue
-HDL = tissue to bile for clearance

-chylomicron and VLDL are mostly trygliceride (biggest)
-LDL is mostly cholesterol
-HDL is mostly protein
-cholesterol is good in portions as we need it for membrane fluidity

Question 15

Processing of Drugs and Hormones:

Answer 15

drugs: into bile then to intestine OR broken down, added to blood, eliminated by kidney

lipid-soluble hormones: thyroid (activation and excretion) and steroid hormones

first pass metabolism = innactive drug form to active form?

Question 16

Fat Soluble Vitamin Storage

Answer 16

lipid-soluble = ADEK

-a = vision support (especially at night)
d = facilitates Ca absorption across duodenum
e = antioxidant
k = used by hepatocytes to make coagulation factors

Question 17

The Gallbladder

Answer 17

label slides
-store and concentrate bile
-bile = produced hepatocytes
-water + cholesterol + bile salts + bilirubin
-bilirubin forms stercobilin to make feces brown

Question 18

Gallbladder Specialized Layer Features

Answer 18

-mucosa = still contains rugae for stretch
-muscularis = one layer of smooth muscle with fibres in all directions
-NO submucosa
-serosa = contains all neurovasculature (instead of the submucosa)
-can live without a gallbladder but must watch what you eat (little fat)

Question 19

Gallbladder Process

Answer 19

1. parasympathetic impulses (vagus nerve) stimulates bile production by liver
2. fat in chyme that enters the duodenum stimulates CCK secretion
   -acidic chyme that enters the duodenum stimulates secretin secretion
3. secretin enhances release of bicarb rich bile salt from liver
   -CCK causes contraction of the gallbladder –> concentrated bile release