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PBDII Exam 5
Dr.Ellis Liver Secretions
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Professional
04/14/2011

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Term
What is the largest gland of the body?
Definition
The liver
Term
List some functions of the liver.
Definition

1. Rids the body of harmful substances

2. Excrete drug metabolites

3. Store nutrients absorbed across gut wall

4. Supply most of the plasma proteins

5. Makes bile

6. Filters blood

Term
What does the first phase of bile secretion contain, and in what %?
Definition

1. Bile acids = 65%

2. Cholesterol = 4%

3. Phosopholipids = 20%

4. Bilirubin = 0.3%

5. Protein = 0.5%

Term
Substances secreted form the liver get secreted into the ____________ then into the __________.
Definition

Bile canaliculi

Bile ducts

Term
What gives bile its yellowish color?
Definition
Bilirubin
Term
When the bile is in the bile duct, it mixes with the _____________ component of the bile that is secreted from the epithelial cells.
Definition
Aqueous
Term
In the 2nd phase of bile secretion, both _______ and ______ have similar [M+] to that of plasma where.
Definition

Na+

K+

Term
The epithelial cells in the 2nd phase of bile secretion have ______ localized in hepatocytes, with a greater [M+] of ____________ than the plasma and a lower __________ than the plasma.
Definition

AQP8

HCO3-

Cl-

Term
Secretory activity of the epithelial cells in the 2nd phase of bile secretion are stimulated by _________________.
Definition
Secretin
Term
T/F: Epithelial cell secretion of aqueous contents account for 50% of the total volume of bile.
Definition
True
Term
From the bile duct, the bile flows into the _____________ and then into the _____________.
Definition

Hepatic duct

common bile duct

Term
Bile secreted by the liver can flow to the ____________ and does flow into the ____________.
Definition

Duodenum

Gall bladder

Term
How much bile can the gallbladder hold?
Definition
15-60 mL
Term
What does the gall bladder epithelium cells do to the bile?
Definition
Extracts salt and water so it concentrates the bile contents.
Term
What things can the gall bladder absorb from the bile?
Definition

1. Na

2. Cl

3. HCO3

4. Water

Term
By what fold does the gall bladder increase the bile acid concentration?
Definition
5-25x
Term
When does gall bladder emptying occur?
Definition
When the walls of the gall bladder contract thus force the bile thru the Sphincter of Oddi into the deudonum. 
Term
_____________ is the most potent stimulus for emptying the gall baldder.
Definition
CCK
Term
How much bile enters the duodenum each day?
Definition
250-1500 mL
Term
What is the main function of bile acids?
Definition
To emulsify fats
Term
When bile acids emulsify fats, what do they increase?
Definition
The surface area available to lipolytic enzymes
Term
Bile acids form _____________ with the products of lipid digestion.
Definition
mixed micelles
Term
What does forming micelles with bile acids enhance?
Definition
The absorption of lipids by the epithelial cells in the terminal ileum.
Term
What chemical property of bile acids allows them to form micelles in solution?
Definition

It is amphipathic

(has hydrophobic inside and hydrophilic  outside regions)

Term
Primary bile acids are synthesized by the _______________ from ______________.
Definition

Hepatocytes

Cholesterol

Term
T/F: 50% of cholesterol is eliminated from the body by making bile acids.
Definition
True
Term
The majority of circulating bile acids are conjugated with ___________ or ____________.
Definition

Glycine

Taurine

Term
T/F: Transcellular transport of bile acids require specialized transporters.
Definition
True
Term
What is meant by enterohepatic circulation?
Definition
The entire bile pool is recirculated 2 or more tiems in response to a typical meal. 
Term
Where are bile acids absorbed?
Definition

In the ileum

 

Term
Bacteria in the ileum and colong ______________ and ______________ bile acids to make secondary bile acids.
Definition

Deconjugate

Dehydroxylate

Term
By deconjugating and dehydroxylating bile acids, the polarity is _________ thus the lipid solubility is ______________ and enhances there absorption by simple diffusion.
Definition

 Decreased

Increased

Term
How does bile acids leave the intestine?
Definition

Leaves in the portal blood

(bound to albumin in plasma)

Term
What extracts bile acids from the portal blood and also resecretes it?
Definition
Hepatocytes
Term
Bile acid in portal blood inhibits synthesis of _________________.
Definition
new bile acids
Term
The stimulation of bile acid secretion is called _____________________.
Definition
Choleretic effect of bile acids
Term
What are choleretics?
Definition
Substances that enhance bile acid secretion
Term
What % of bile acids escape absorption and is excreted?
Definition
10-20%
Term
T/F:  Bile acid lost into the feces are the only significatn source of cholesterol excretion.
Definition
True
Term
What happens if there is an excess of cholesterol in the bile?
Definition

Can be solubilized in micelles.

Bile is now supersaturated with cholesterol

Crystals of cholesterol form in the bile

=

cholesterol gallstones

Term
Where can cholesterol gallstones form?
Definition

In the duct system of the liver

or

the gallbladder

Term
What is cholestasis?
Definition

Accumulation of bile salts in the blood and a deficiency of bile salts in the intestinal lumen.

Decreased bile flow thru the canaliculi

Term
What is bilirubin a product of?
Definition
Degraded RBC
Term
Bilirubin is released in the ____________.
Definition
Plasma
Term
Which specific moeity of Hb is converted to Bilirubin?
Definition
Porphyrin
Term
What removes bilirubin from the blood and what does it then conjugate with to form what?
Definition

Hepatocytes

Conjugates with glucuronic acid to borm bilirubin glucuronides

Term
Where are bilirubin glucuronides secreted into?
Definition
The Bile
Term
Colonic bacteric converts bilirubin to _______________, which can then be absorbed into the blood, excreted in urine, or taken up by hepatocytes to be resecreted into bile.
Definition
Urobilinogen
Term
What makes up bile pigment gallstones?
Definition
Calcium salts of unconjugated bilirubin
Term
Conjugated bilirubin is _____________ so does not form salts.
Definition
Soluble
Term
In liver disease, why may the bile contain elevated levels of unconjugated bilirubin?
Definition
Because hepatocytes are deficient in forming the bilirubin glucuronides.
Term
What things does the Duedoenal epithelial cells secrete?
Definition

1. Mucus

2. Aqueous component (close to plasma)

Term
How much does the intestine secrete in a day?
Definition
1500 mL/day
Term
________________ lines the columnar epithelial cells of the S.I. and secretes mucus.
Definition
Goblet cells
Term
T/F:  During normal digestion, aqueous secretion is made by the epithelial cells faster than the rate of fluid absorption by the S.I.
Definition
False; it's at a rate slower than the the rate of fluid absorption by the S.I.
Term
There are also goblet cells in the colon that secrete mucus.  The aqueous component of colon secretion is rich in ____________ and ___________.
Definition

K+

HCO3-

Term
What kind of agents stimulate colon secretion?
Definition
Cholinergics
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