17 - Physiology of Liver & Pancreas Flashcards
1
Q
What is the blood flow through the liver lobule starting in the portal vein?
A
Portal vein – Sinusoids – Central vein – Hepatic veins
2
Q
What is the blood flow through the liver lobule starting in the hepatic artery?
A
Hepatic artery – Sinusoids – Central vein – Hepatic veins
3
Q
Liver cell plates are composed of two layers of __________.
A
Hepatocytes
4
Q
_______ _______ lie between the two layers of hepatocytes in each cell plate.
A
Bile canaliculi
5
Q
Sinusoids are lined with what?
A
Endothelial cells
Kupffer cells
6
Q
This is what is found between endothelial cells and hepatocytes.
A
Space of Disse
7
Q
The liver has a (HIGH/LOW) blood flow and (HIGH/LOW) vascular resistance.
A
High
Low
8
Q
_______ ml from the portal vein + _______ ml from the hepatic artery flows into sinusoids each minute.
A
1050
300
9
Q
What percentage of the resting cardiac output is in the liver?
A
27 percent
10
Q
What is the portal pressure into the liver?
A
9 mmHg
11
Q
What is the pressure from the liver to the vena cava?
A
0 mmHg
12
Q
________ increases blood resistance to blood flow.
A
Cirrhosis
13
Q
The effect of a clot blocking the portal vein or a major branch results in the blockage of return blood from the _______ and _______.
A
Spleen
Intestines
14
Q
The effect of a clot blocking the portal vein or a major branch can result in an (INCREASE/DECREASE) in capillary pressure in the intestinal wall, leading to loss of fluid and death.
A
Increase
15
Q
The normal volume of the liver is _____ ml, which is _____ percent of the body’s blood volume.
A
450
10
16
Q
What happens when there is high pressure in the right atrium in the occurrence of cardiac failure with peripheral congestion?
A
Causes backpressure on the liver and leads to increased blood volume in the liver up to 1.5 liters
17
Q
T/F. The liver can store blood in times of excess and supply blood in times of diminished volume.
A
True
18
Q
Hepatic sinusoids are highly permeable to ________.
A
Proteins
19
Q
Higher than normal pressure in hepatic veins can cause a large amount of fluid in the abdominal cavity, which is called _________.
A
Ascites
20
Q
Functions of carbohydrate metabolism in the liver includes:
- Storage of glucose as ________
- Converts _______ and _______ to glucose
- Gluconeogenesis
- Forms many intermediate products of carb metabolism
- Releases stored glucose into circulation
A
Glycogen
Galactose
Fructose
21
Q
Functions of fat metabolism in the liver includes:
- Oxidation of ______ _____ for energy
- Synthesis of cholesterol, phospholipids, lipoproteins
- Synthesis of fats from proteins and carbohydrates
A
Fatty acids
22
Q
Functions of protein metabolism in the liver includes:
- ________ of amino acids
- Formation of urea
- Formation of plasma proteins
- Interconversion of various amino acids and synthesis of other compounds from amino acids
A
Deamination
23
Q
The liver stores what vitamins?
A
Vitamin A
Vitamin D
Vitamin B12
24
Q
T/F. The liver does not possess any immune function.
A
False. It does have immune function.
25
The liver functions in the formation of which coagulation factors?
Fibrinogen
Prothrombin
Accelerator globulin
Factors VII, IX, X
26
The liver removes or excretes drugs, hormone, and other substances. It detoxifies or excretes it into the _______.
Bile
27
The liver excretes excess _______ into the bile.
Calcium
28
The liver also detoxifies and removes _______ and _______.
Ammonia
| Ethanol
29
Potentially toxic substances are presented to the liver via the portal system. Phase I reactions are catalyzed by ______ enzymes, then Phase II reactions conjugate products from Phase I reactions and are excreted in the bile.
P-450
30
Sulfonamides, penicillin, ampicillin, and erythromycin are all excreted from the liver by the ______.
Bile
31
Note that bile is secreted continuously by hepatocytes in the liver and stored in the ______ ______ until needed.
Gall bladder
32
In the gall bladder, bile is concentrated by active transport of _______ followed by secondary absorption of _______ ions, _______, and other diffusible constituents.
Sodium
Chloride
Water
33
What factors stimulate the release of bile from the gall bladder?
Presence of fatty food in duodenum
34
Bile salts are amphipathic and orient themselves around lipid droplets to keep them dispersed, this is called __________.
Emulsification
35
Bile salts complex with lipids to form micelles. They are positioned on the outside of the micelles for absorption across ________ ________.
Intestinal mucosa
36
What are inside the micelles that are complexed with the bile salts?
Free fatty acids
| Monoglycerides
37
What are the primary bile acids that are synthesized from cholesterol by hepatocytes?
Cholic acid
| Chenodeoxycholic acid
38
Bacteria in the intestine convert the primary bile acids into secondary bile acids, which are...
Deoxycholic acid
| Lithocholic acid
39
Bile acids are conjugated with ________ or ________ and electrolytes and water are added to bile.
Glycine
| Taurine
40
Bile is (CONCENTRATED/DILUTED) in the gallbladder as a result of absorption of solutes and water.
Concentrated
41
Bile also contains pigments and organic molecules. The major pigment is ________.
Bilirubin
42
This is what is released from damaged RBCs.
Hemoglobin
43
Hemoglobin is phagocytized by macrophages (reticuloendothelial system). Here it is split into globin and heme. The heme ring is opened to free iron and is transported in the blood by transferrin. Straight chain of pyrrole nuclei is formed. Heme is converted by heme oxygenase into _________, which is then converted to free (unconjugated) bilirubin.
Biliverdin
44
Free bilirubin is transported in the blood stream attached to plasma ________ to liver hepatocytes.
Albumin
45
Free bilirubin is released from plasma albumin within the liver cells and conjugated. 80 percent of it is conjugated with _________ acid by the enzyme UDP glucuronyl transferase into ________ _______.
Glucuronic
| Bilirubin glucuronids
46
10 percent of bilirubin can also be conjugated with ________ and turned into bilirubin sulfate.
Sulfate
47
Conjugated bilirubin is secreted (active transport) into the ________ or excreted into the ________.
Intestine
| Urine
48
Conjugated bilirubin in the small intestine is converted to _________ via bacterial action in the terminal ileum. From here it is oxidized into ________ and _______ in the colon and excreted in the feces.
Urobilinogen
Urobilin
Stercobilin
49
Conjugated bilirubin in the small intestine is converted to _________ via bacterial action in the terminal ileum. From here it goes to enterohepatic circulation then the liver, where it is re-excreted by the liver or excreted in the urine.
Urobilinogen
50
This refers to a yellowish tint to the body tissues. It is usually caused by quantities of bilirubin in the extracellular fluids.
Jaundice
51
Jaundice is commonly caused by increased ________ or obstruction of bile ducts or damage to liver.
Hemolysis
52
This is a major type of pancreatic islet cell that secretes glucagon and consists of 25 percent of total cells.
Alpha
53
This is a major type of pancreatic islet cell that secretes insulin and amylin and consists of 60 percent of total cells.
Beta
54
Insulin inhibits ________ secretion, and amylin inhibits _______ secretion.
Glucagon
| Insulin
55
This is a major type of pancreatic islet cell that secretes somatostatin, which inhibits insulin, glucagon, and gastrin secretion.
Delta
56
In communication among islet cells, beta cells to beta cells, alpha cells to alpha cells, and beta cells to alpha cells all communicate via...
Gap junctions
57
In communication among islet cells, beta cells to alpha and delta cells communicate via...
Islet portal blood supply
58
Pancreatic exocrine functions include digestive enzymes for proteins. These enzymes are...
Trypsin
Chymotrypsin
Carboxypolypeptidase
59
The pancreas also has a trypsin inhibitor that is secreted by the _______ cells. This inhibitor is necessary to prevent the action of trypsin on the pancreatic tissues themselves.
Glandular
60
Pancreatic exocrine functions include digestive enzymes for carbohydrates, which are...
Pancreatic amylase
61
Pancreatic exocrine functions include digestive enzymes for fat, which are...
Pancreatic lipase
Cholesterol esterase
Phospholipase
62
Pancreatic secretions have high volume and are ________.
Isotonic
63
Pancreatic secretions have the same _______ and _______ ion concentrations as plasma, but have a higher _______ concentration than plasma and a lower _______ ion concentration that plasma.
Sodium
Potassium
Bicarbonate
Chloride
64
If pancreatic secretions have low flow rates that means the isotonic fluid is composed mostly of _______ and _______ ions.
Sodium
| Chloride
65
If pancreatic secretions have high flow rates that means the isotonic fluid is composed mostly of _______ and _______ ions.
Sodium
| Bicarbonate
66
These cells produce a small volume of pancreatic secretion composed mainly of sodium and chloride ions.
Acinar cells
67
These cells in pancreatic secretion will secrete bicarbonate ion and reabsorb chloride ion via a chloride-bicarbonate exchange mechanism. Ducts are permeable to water, so water moves into ducts to make secretion isotonic.
Ductal cells
68
This is from parasympathetic nerves and enteric nervous system. It is released in response to hydrogen ions, small peptides, amino acids, and fatty acids in the duodenum.
Acetylcholine
69
Acetylcholine stimulates enzyme secretion by acinar cells and potentiates effect of _______.
Secretin
70
The release of this is stimulated by the presence of food in the upper intestine, especially small peptides, amino acids and fatty acids. It is secreted by the duodenal and upper jejunal mucosal I cells.
Cholecystokinin
71
The release of cholecystokinin results in a dramatic increase in secretion of pancreatic enzymes. It potentiates the effect of secretin on ductal cells to stimulate _________ secretion.
Bicarbonate
72
In cholecystokinin, second messengers are ______ and increased intracellular _______.
IP3
| Calcium
73
This pancreatic secretion release is stimulated by the presence of acidic foods in the upper intestine. It is secreted by the duodenal and upper jejunal S mucosal cells.
Secretin
74
Secretin stimulates the release of large amounts of ________ ________ by ductal cells. Its second messenger is ________.
Sodium bicarbonate
| cAMP
75
Insulin circulates in unbound form in the blood with a half-life of 6 minutes. Insulin not bound to receptors is destroyed in the _______.
Liver
76
Insulin is synthesized in beta cells by the usual cell machinery for protein synthesis, beginning with translation of the insulin RNA by ribosomes attached to the ER to form __________.
Pre-proinsulin
77
This initial pre-proinsulin is cleaved in the ER to form a proinsulin consisting of three chains of peptides, ______, ______, and ______.
A
B
C
78
Most of the proinsulin is further cleaved in the Golgi apparatus to form insulin, which is composed of the A and B chains connected by ________ linkages, and the C chain peptide, called connecting peptide. The insulin and C peptide are packaged in the secretory granules and secreted.
Disulfide
79
To initiate its effects on target cells, insulin first binds with and activates a membrane receptor protein. This insulin receptor is a combination of four subunits held together by disulfide linkages: Two _______ subunits that lie entirely outside the cell membrane and two _______ subunits that penetrate through the membrane, protruding into the cell cytoplasm.
Alpha
| Beta
80
The insulin binds with the (ALPHA/BETA) subunits on the outside of the cell, but because of the linkages with the (ALPHA/BETA) subunits, the portions of the (ALPHA/BETA) subunits protruding into the cell become autophosphorylated.
Alpha
Beta
Beta
81
Autophosphorylation of the beta subunits of the insulin receptor activates a local ______ ______, which in turn causes phosphorylation of multiple other intracellular enzymes.
Tyrosine kinase
82
The result of insulin binding to a receptor includes the increased uptake of ________, making the blood glucose decrease.
Glucose
83
The result of insulin binding to a receptor includes a (INCREASED/DECREASED) amount of blood amino acids and potassium, as well as (INCREASED/DECREASED) permeability to amino acids, potassium and phosphate ions.
Decreased
| Increased
84
The result of insulin binding to a receptor includes the increased uptake of ______ ______, meaning there are less in the blood.
Fatty acids
85
Insulin down-regulates its own receptors. Receptors are (INCREASED/DECREASED) in starvation and (INCREASED/DECREASED) in obesity.
Increased
| Decreased
86
Most of the glucose absorbed after a meal is stored as ________ in the liver.
Glycogen
87
In the glucose uptake mechanism for the liver, insulin inactivates liver __________ and insulin activates ________ and enhances the uptake of glucose from blood.
Phosphorylase
| Glucokinase
88
In the glucose uptake mechanism for the liver, insulin increases activities of enzymes needed for _________.
Glycogenesis
89
One of the most important functional roles of insulin in the body is to control from moment to moment whether ______ (higher insulin) or _______ (lower insulin) will be used by cells for energy.
Fat
| Carbohydrate
90
For liver to release glucose back into blood, there must a decreased level of blood glucose resulting in decreased ________ secretion. Lack of ________ reverses glycogen synthesis pathway.
Insulin
| Insulin
91
For liver to release glucose back into blood, there is a lack of insulin which activates phosphorylase which then splits glycogen into ________ and ________.
Glucose
| Phosphate
92
________ ________ removes phosphate from glucose and allows it to diffuse back into blood.
Glucose phosphatase
93
T/F. Insulin inhibits gluconeogenesis.
True
94
Insulin promotes the conversion of excess glucose into ______ ______ and decreases the utilization of fat.
Fatty acids
95
Insulin increases the transport of glucose into the liver, creating excess. Excess glucose is then converted to _______. Fatty acid synthesis is initiated. Newly synthesized fatty acids are converted into _________ and transported from liver as lipoproteins.
Acetyl-CoA
| Triglycerides
96
Triglycerides are split back into fatty acids in capillaries and taken up into fat cells. Insulin promotes uptake of _______ by fat cells.
Glycerol
97
When there is a lack of insulin on fat storage, all the effects are reversed and large amounts of _______ and fatty acids are released into the blood.
Glycerol
98
When there is a lack of insulin, large amounts of acetoacetic acids are formed in the liver. Carnitine transport mechanism in the liver is activated. Beta-oxidation results in excess of acetyl-CoA. Excess acetoacetic acids cause acidosis and there is an increase of _______ _______ in the blood.
Ketone bodies
99
This acts on the liver and adipose tissue and its major effects are the break down of liver glycogen and increased gluconeogenesis. This leads to increased blood glucose.
Glucagon
100
Put the following events of glucagon leading to the increase in blood glucose in order from first to last --
A. Which activates protein kinase
B. Which converts phosphorylase b into phosphorylase a
C. Activates adenyl cyclase in hepatic cell membrane
D. Which causes formation of cAMP
E. Which activates phosphorylase b kinase
F. Increased blood glucose
G. Which promotes degradation of glycogen to glucose 1-phosphate
1. C
2. D
3. A
4. E
5. B
6. G
7. F
101
Glucagon increases lipolysis, which increases blood fatty acids and leads to increased blood ______ acids.
Keto
102
Glucagon increases ______ production (due to deamination of amino acids used for gluconeogenesis).
Urea
103
Note that the major factor that regulates glucagon secretion is the concentration of...
Blood glucose
104
Increased blood amino acids stimulates glucagon secretion. It prevents ________ due to unopposed insulin in response to high protein meal.
Hypoglycemia
105
This is secreted by delta cells and it inhibits the secretion of insulin, glucagon, and gastrin. It also decreases the motility of the stomach, duodenum, and gallbladder as well as decreases the secretion and absorption of the GI tract.
Somatostatin
106
Negative effects of increased blood glucose levels includes increased osmotic pressure in the extracellular fluid, loss of glucose in _______, osmotic diuresis (dehydration and loss of electrolytes), and damage to tissues and blood vessels.
Urine
107
This type of diabetes is due to a lack of insulin secretion. There are injury to beta cells, such as viral infections or autoimmune disorders.
Type I (IDDM)
108
This type of diabetes is due to insulin resistance. Obesity is a major risk factor, and it is preceded by the metabolic syndrome.
Type II (NIDDM)
109
The metabolic syndrome for Type II diabetes mellitus includes obesity (especially abdominal fat), insulin resistance, fasting _________, increased lipid triglycerides, decreased HDL levels, and hypertension.
Hyperglycemia
