Accessory Digestive Organs (Lec 19) Flashcards
1
Q
What are the liver and pancreas embryological outgrowths of?
A
- primitive gut
2
Q
What is the largest gland and internal organ?
A
- liver
3
Q
How many lobes does the liver have?
A
- 4
right, left, quadrate, caudate
4
Q
What are the main functions of the liver?
A
- detoxification of metabolic waste
- metabolism and detoxification of drugs and toxins (e.g. alcohol, abx)
- destruction of senescent rbc’s
- recycling of Hb via synthesis and secretion of bile
- synthesis of plasma proteins
- miscellaneous metabolic functions
5
Q
What is an example of livers role in detoxification of metabolic waste?
A
- deamination of AA’s to urea
6
Q
Sometimes priest would examine the liver after a sacrifice
A
- bad omen would be abscess or flukes coming out
7
Q
Does the liver have a role in detoxification of drugs?
A
- YES
8
Q
T/F the liver does not destruct senescent rbc’s
A
- False
9
Q
T/F the liver recycles of hemoglobin via synthesis and secretion of bile
A
- True
10
Q
Can the liver synthesize plasma proteins?
A
- Yes
clotting factors, albumin, lipoproteins
11
Q
What are the miscellaneous metabolic functions of the liver?
A
- Glycogen synthesis, and storage, gluconeogenesis
12
Q
What covers the external surface of the liver?
A
- connective tissue capsule called Glisson’s capsule
13
Q
Where do monosaccharides and AA’s from digestion enter the liver?
A
- hepatic portal vein
14
Q
What vein carries about 75-80% of blood to liver?
A
- hepatic portal vein
15
Q
Is the blood in the hepatic portal vein oxygenated or deoxygenated?
A
- deoxygenated (coming from tissues of gut that have been drained)
16
Q
What else does the hepatic portal vein carry?
A
- potentially toxic compounds absorbed from diet to liver to be conjugated or detoxified
17
Q
What supplies the liver with oxygenated blood?
A
- hepatic artery –> portal artery in hepatic lobules
18
Q
Where does the hepatic artery branch off from?
A
- celiac artery
19
Q
What carries about 20-5% of blood to the liver and mixes with unoxygenated blood from portal V?
A
- portal artery
20
Q
T/F the liver is nutrient rich and oxygen rich environment?
A
- False
the liver is nutrient rich but oxygen poor environment
21
Q
what is the pathway of venous drainage of lobules?
A
- central vein to hepatic vein to IVC
22
Q
What are liver cells called?
A
- hepatocytes
23
Q
Are most hepatocytes single nucleus?
A
- most are diploid but some polyploid or binucleate
24
Q
_____ contain large numbers of cytoplasmic granules (rough ER and lysosomal products) and storage products
A
- hepatocytes
25
Aging hepatocytes accumlate brown pigment _____
- lipofuscin
26
How are individual hepatocytes shaped?
- polygonal
27
How are individual hepatocytes arranged?
- arranges in anastomosing cords paralleled by venous sinusoids
28
sinusoids are lined by ___________ a discontinuous endothelium with gaps between endothelial cells
- sinusoidal lining cells
29
What is the space between sinusoidal lining cells and hepatocytes?
- space of Disse (=perisinusoidal space)
30
How is space of disse different in lymphatics
- it is continuous
31
What supports hepatic cords and sinusoids?
- reticulin fibers (type III collagen)
32
Within sinusoids and space of Disse are phagocytic ______ cells
- Kupffer cells
33
Occasion fat storing cells in liver?
- Ito cells
34
What do Ito cells do?
- contain lipid droplets used for Vit A and D storage
35
Caud liver oil
- now comes from livers of shark
| - have lots of oil in liver to make them buoyant
36
Seals have high quanities in Vit A and D in liver
- because they eat lots of fish
37
Polar bears
- eat seals and have so much Vit A and D in liver its toxic
| - eat the fat because its highest in energy
38
How are cords of hepatocytes arranged?
- in lobules
39
what is the classic lobule based on?
- blood flow
40
What is the shape of classic lobule?
- roughly hexagonal with central vein in middle of lobule
41
Cattle and pig lobules
- outer margin of each lobule delimited by thin connective tissue septum
42
Portal triad
- portal artery, portal vein, bile
duct
(also contain lymphatics but tough to see)
43
Where are the portal triads located?
- at each "corner"
44
What is the pathway of blood in liver?
- enters form portal tracts, percolates through sinusoids of lobule and drains via central vein
45
what is the shape of portal lobule?
- triangular
46
What is portal lobule based on?
- bile flow
47
How is portal lobule arranged?
- portal triad in center and central vv at corners
48
What is the shape of acinus lobule?
- diamond shaped region between neighboring central veins
49
How are the central veins oriented in acinus lobule?
- central veins located along longitudinal axis with portal tracts at side
50
Why is acinus so popular?
- combines aspects of blood flow, oxygenation, metabolism, and pathology
51
what is the least popular lobule arrangement?
- portal lobule
52
How many zones is the acinus divided into?
- 3
53
Hepatocytes in different zones have ______ metabolic environments
- different
54
Which zone is closest to the portal tract and receives the most oxygenated blood?
- zone 1 or ( perilobular zone/periportal)
55
What zone is most susceptible to toxic injury?
- zone 1
56
What zone is most susceptible to ischemic injury?
- zone 3
| receives the least oxygenated blood
57
Zone 2 is the _______ zone
- intermediate
58
Which zone is closest to the central V and furthest from the portal tract?
- zone 3
59
_______ functions in detoxification or metabolism of various drugs, toxins, metabolites (e.g ethanol, pesticides, and carcinogens) via microsomal mixed function oxidase system of sER or peroxidases of peroxisomes (P450 system)
- liver
60
A common sequela to repeated insults or chronic disease of liver is _____
- cirrhosis
61
______ is characterized by hepatic degeneration and necrosis followed by fibrosis and nodular regeneration
- cirrhosis
62
_______ associated with cirrhosis (due to fibrosis and blockage of blood flow)
- portal hypertension
63
Can the liver regenerate
- Yes
| a little as 1/3 of liver can lead to regrow full liver
64
T/F Liver has both endocrine and exocrine functions?
- True
65
Exocrine means
- via ducts
66
Endocrine means
- directly into bloodstream
67
What are the endocrine functions of the liver?
- synthesis of plasma proteins
- synthesis of glucose
- gluconeogenesis (from non-carb sources like amino acids and lipids)
- storage and release of glycogen, lipids, and lipoproteins
- vit A and D storage
68
Exocrine function of the liver is ?
- bile synthesis
69
_____ is an emulsifying agent, facilitates hydrolysis of lipids by pancreatic lipases
- bile
70
How much bile does the adult human liver secrete per day?
- 1 liter per day
71
What hormones increases bile flow from the liver?
- secretin, CCK, and gastrin from enteroendocrine (APUD) cells
72
Snake bile
- used as aphrodisiac
| - choose your snake
73
What synthesizes bile?
- hepatocytes
74
Where is bile secreted?
- into network of bile canliculi
75
What are bile canaliculi?
- small canals between hepatocytes, formed by groves in plasma membranes of adjacent cells
76
Direction of bile flow is ______ to blood from, from canaliculi, in series of progressively larger ducts
- opposite
77
Bile synthesis
- includes bile ducts (portal triads) and larger intrahepatic ducts (scattered throughout parenchyma)
78
Where does bile eventually enter duadenum?
- major duodenal papilla following a period of storage and modification in gallbladder
79
What is the gallbladder (colossus)
- muscular sac lovated in depression along surface of liver that is used to store and concentrate bile
80
What lines the gallbladder?
- simple columnar epithelium with apical microvilli used for resorption of water
81
Does the gallbladder have a muscularis mucosae?
- nope
82
What is the lamina propria in the gallbladder like?
- highly folded with occasional tubuloalveolar mucus glands
83
What stimulates the contraction of gallbladder?
- CCK
84
Do horses and rats have a gallbladder?
- no they dont store bile
85
What is bile made of?
- water, ions, electrolytes, cholesterol + phospholipids (lecithin) bile acids (= bile salts) and bile pigments
86
What is the best know bile pigment?
- bilirubin
87
What is bilirubin?
- non soluble breakdown product of hemoglobin
88
What is bilirubin glucuronide?
- water soluble form of bilirubin, conjugated with glucuronide
89
What happens when you cant absorb bilirubin or conjugate it and secrete glucuronide?
- accumulation of bile pigments and jaundice
(dark olive green produces yellow color) can be result of liver failure
90
What happens when there is a supersaturation of bile?
- gallstones (biliary calculi, choleithiasis)
91
What are gallstones made of?
- primary cholesterol and calcium salts
92
Chronic inflammation from gallstones is?
- cholecystitis
93
Obstruction of bile ducts (choledocolithiasis) leads to?
- bile stasis or jaundice (if severe)
94
How do you treat choledocolithiasis?
- cholecystectomy
95
What happens when your gallbladder is removed?
- unable to concentrate bile so you need to limit fat intake
96
_____ is highly loblated gland with think connective tissue capsule located in bend of duodenum
- pancreas
97
Where does pancreas come from?
- embryological outgrowth of primitive gut
98
Does pancreas have endocrine or exocrine functions?
- both
99
ductless endocrine pancreatic tissue is located in ______
- islets of Langerhans
100
Most of the pancreas is ______ a compound, acinar, serous gland
- exocrine
101
Densely packed serous acini contain pyramidal secretory cells surrounding a _____
- central lumen (duct)
102
Acinar cells contain _____
- zymogen granules (inactive enzyme precursors)
103
What are the zymogens that the acinar cells contain?
- trypsinogen (= protrypsin)
- chymotrypsinogen (=prochymotrypsin)
- amylase and lipase
104
What are trypsin and chymostrypsin?
- proteases
105
What does amylase break down?
- carbohydrates
106
What does lipase break down?
- lipids
107
Where do these enzymes empty into?
- intercalated ducts
108
What is the duct that forms at the beginning of intercalated duct?
- centro-acinar cells
109
What do intercalated ducts do?
- add bicarbonate and water to pancreatic sections to neutralize acidic chyme from stomach which creates optimal pH for pancreatic enzymes
110
What do intercalated ducts empty into?
-larger intralobular ducts
111
Where do intralobular ducts exit into?
- interlobular (extralobular) ducts
112
Where do pancreatic secretions enter duodenum?
- via the pancreatic duct at the major duodenal papilla
113
What are the principle regulators of exocrine pancreas?
- polypeptide hormones secreted by enteroendocrine (APUD) cells
114
What are the poly peptide hormones that regulate panceras?
- gastrin
- secretin
- CCK
- enterokinase
115
What secretes gastrin?
- stomach
116
What are the hormones secreted by the duodenum?
- secretin
- CCK
- enterokinase
117
What does secretin do?
- secreted by "S" cells
| - stimulates secretion of bicarbonate by cells of intercalated ducts
118
What does CCK (cholecystokinin = pancreozymin) do?
- secreted by I cells
| - stimulates acinar cells to secrete zymogens
119
What does enterokinase do?
- converts trypsinogen iinto trypsin (within small intestine) which conterts chymotrypsinogen to chymotrypsin (digests proteins)
- cascade reaction prevents pancrease from digesting itself
120
_______ is auto-digestion of pancreas brought on by alcoholism
- pancreatitis
121
What leads to pancreatitis?
- the cascade reaction breaks down which leads to premature conversion of chymotrypsinogen to chymotrypsin and autolysis
122
Severe acute pancreatitis can be fatal within____
- hours
