Digestive System Ii Associate Glands Chiaia Anatomy Block Ii Unit Ii

Front 1

What is an endocrine function?

Back 1

Directly into blood stream.

Front 2

WHat is an exocrine secretion?

Back 2

Into duct

Front 3

What does the liver serve as an interface between?

Back 3

The blood (distrubutes nutrients) and the digestive system (extracts nutrients).

Front 4

What are the 3 functions of the liver?

Back 4

Vascular function
Secretory/excretory functions
Metabolic functions

Front 5

What are the vascular functions of the liver?

Back 5

storage and filtration of blood

Front 6

What are the secretory/excretory functions of the liver?

Back 6

Vitamin storage and excretion, A, B12, C, D, E, K, also blood clotting stuff, synthesis and secretion of bile

Front 7

What are the metabolic functions of the liver?

Back 7

-Protein synthesis (albumin, prothrombin, fibrinogen)
-lipoprotein and cholesterol synthesis
-carbohydrate metabolism (glycogenesis, glycogenolysis, gluconeogenesis)
-Metabolism of lipid-soluble drugs and steriods
-Urea formation (from ammonium ions)

Front 8

Where is the liver located?

Back 8

Upper right quadrant, below the diaphragm

Front 9

What does the liver look like in the living state? (color)

Back 9

Reddish brown

Front 10

What is Glisson's capsule?

Back 10

A dense irregular CT capsule that covers the liver and is itself coverd by the mesothelioum of the peritoneum.

Front 11

What is the portal hepatis? What goes through it?

Back 11

A short transverse fissure that serves as the site of entry and exit of blood vessels, lymphatics, nerves and ducts.

Front 12

What seperates the right and left lobes of the liver?

Back 12

The falciform ligament.

Front 13

Approximately how much of the total cardiac output of the heart does the liver consume?

Back 13

1/3

Front 14

What percentage of the blood supply of the liver comes from the hepatic portal vein?

Back 14

75%

Front 15

What forms the hepatic portal vein?

Back 15

Capillaries of the digestive tract, spleen, and pancreas

Front 16

What do the portal veins give rise to? What do these vessels carry?

Back 16

Smaller diameter distributing veins andd inlet venules which radiate outward toward the sinusoids. They carry nutrient rich blood.

Front 17

What percentage of the liver's blood supply comes from left and right hepatic arteries?

Back 17

25%

Front 18

What is the origin of the left and right hepatic arteries? What is the origin of that origin?

Back 18

Celiac trunk -> Abdominal aorta

Front 19

What do hepatic arteries give rise to? What do these vessels do?

Back 19

Smaller distributing arterioles and inlet arterioles. These carry oxygen rich blood to the hepatocytes.

Front 20

WHat do inlet arterioles and venules empty into? What do these structures seperate?

Back 20

The inlet arterioles and venules empty into endothelially line sinusoids which separate the plates of hepatocytes in the parenchyma.

Front 21

What do the sinusoids of the liver empty into? Where are these structures located and what are they called?

Back 21

Terminal hepatic venules at the center of each liver lobule, called central veins.

Front 22

What do central veins empty into? What do these vessels eventually form/drain into?

Back 22

Progressively larger veins, sublobular veins, and collecting veins that eventually form the left and right hepatic veins.

Front 23

What shape are hepatocytes arranged in? What are they surrounded by?

Back 23

Hexagonal shape. Surrounded by CT.

Front 24

What is the area of denser connective tissue between the lobules of the liver called? What can be found here?

Back 24

The portal tract which contains the major vessels of the liver (hepatic artery, hepatic portal vein, lymph vessels, bile duct).

Front 25

What makes up the triad of vessels in the liver?

Back 25

Hepatic artery, hepatic portal vein, bile duct.

Front 26

Describe the cells lineing the bile duct.

Back 26

Cuboidal cells w/ centrally located nucleus, looks like a string of pearls.

Front 27

What two things separates the portal tract from the parenchyma of the lobules? Describe them.

Back 27

Space of Moll (a narrow space, thought to be the site of origin of hepatic lymph)

Limiting Plate- A sleeve of modified hepatocytes.

Front 28

Describe the arrangements of hepatocytes of lobules.

Back 28

Plates or cords separated by sinusoids.

Front 29

What pierces the center of each lobule of the liver? What does it do?

Back 29

The center vein which drains blood from the sinusoids.

Front 30

What are the 3 concepts of the liver lobule?

Back 30

Classic lobule, portal lobule, hepatic lobule

Front 31

What defines the classic lobule?

Back 31

A hexogonal shaped parenchymal region and bounded by portal tracts at each corner of the hexagon with a central vein at its center.

Front 32

Why is lobulation indistinct in humens?

Back 32

Sparse perilobular CT

Front 33

What is the basis for the classic lobule?

Back 33

CT arrangement

Front 34

Within the classic liver lobule where does blood flow and in what and from what?

Back 34

From portal triads, centrally toward the central vein via the sinusoids

Front 35

Within the classic liver lobule where does bile flow and in what and from what?

Back 35

Bile flows from the hepatocytes, peripherally towards the bile ducts in the portal region.

Front 36

Fill in the blank!

The __________ of each lobule collects blood from all ________ in that lobule and empties into the __________ which gives rise to a _________ which eventually joins the ___________

Back 36

The CENTRAL VEIN of each lobule collects blood from all SINUSOIDS in that lobule and empties into the SUBLOBULAR VEIN which gives rise to a COLLECTING VEIN which eventually joins the RIGHT OR LEFT HEPATIC VEINS.

Front 37

What defines a lobule in the portal lobule description? What would this be in the liver?

Back 37

A region of the parenchyma whose secretory units flow into a common interlobular duct. In the liver this would be the bile duct of the portal tract.

Front 38

What is the portal lobule described in terms of?

Back 38

Bile flow

Front 39

What is the portal lobule defined as?

Back 39

A triangular region of hepatocytes with a central vein at the apices of the triangle and the portal triad (with the accompanying bile duct) at the center.

Front 40

Where does bile flow in the portal lobule?

Back 40

Bile flows from teh periphery to the center of the portal lobule into the interlobular bile duct.

Front 41

Describe the size of the hepatic portal acinus.

Back 41

Smallest functional unito f the liver

Front 42

Give the arrangement of veins and hepatocytes within the hepatic portal acinus.

Back 42

A diamond-shaped mass of hepatocytes lying between two central veins at the apices of its long axis and two portal tracts at apices its short axis.

Front 43

What transverses the meridian of the diamond of hepatocytes in the hepatic portal acinus model?

Back 43

Preterminal branches of a distributing arteriole which supplies blood to the sinusoids.

Front 44

In the portal acinus model hepatic cords are supplied by each arterial branch are divided into how many zones?

Back 44

3 functional zones.

Front 45

Describe zone 1 of the portal acinus model, where are its cells, what sort of blood does it recieve and what is its exposure to waste?

Back 45

Cells closest to the arteriole and meridian
Recieves an excellent supply of oxygenated blood and nutrients
Minimally exposed to metabolic waste

Front 46

Describe zone 2 of the portal acinus model, where are its cells, what sort of blood does it recieve and what is its exposure to waste?

Back 46

Cells further from vessels than zone 1, receive only moderately oxygenated blood, intermediate exposure to metabolic waste.

Front 47

Describe zone 3 of the portal acinus model, where are its cells, what sort of blood does it recieve and what is its exposure to waste?

Back 47

Cells closest to cental vien, recieves poorly oxygenated blood, high exposure to metabolic waste.

Front 48

Which zone is the primary site of alcohol and drug detox? What are they more vulnerable to?

Back 48

Zone 3 hepatocytes are more vulnerable to toxic damage than zone 1, liver disease usually shows degeneration of zone 3 cells first.

Front 49

Within each lobule hepatocytes are arranged in thin cords or plates 1 or 2 cells thick. These are separated by what?

Back 49

Thin endothelially lined sinusoids.

Front 50

What sort of structure do the hepatic plates form?

Back 50

A continuously anastomosing labyrinth of cells.

Front 51

What do the sinusoids form within the lobule? Where do they ultimately empty?

Back 51

A continuosu vascular channel within the lobule that ultimately empties in the central vein at the center of the lobule.

Front 52

Are hepatocytes in direct contact with the sinusoids?

Back 52

NO!

Front 53

What separates hepatocytes from sinusoids?

Back 53

A thin perisinusoidal space (space of Disse)

Front 54

What does the space of Disse contain? (fluid)

Back 54

Blood plasma but not blood cells or platelets.

Front 55

What sort of structures are there many of in the space of disse?

Back 55

Numerous microvilli protruding from the surface of hepatocytes.

Front 56

What are perisinusoidal cells of Ito? Where are they found? What do they do?

Back 56

Irregular cells with long cytoplasmic processes which concentrate vitamin A.

Front 57

What sort of cell type form the wall of hepatic sinusoids?

Back 57

Simple squamous endothelial cells.

Front 58

Describe the endothelial cells of the wall of the hepatic sinusoids.

Back 58

Discontinuous without a continuous basal lamina.

Front 59

Describe the membrane of endothelial cells of hepatic sinusoids.

Back 59

Riddled with clusters of small holes (Sieve plates)

Front 60

What sort of things cannot pass through hte endothelial wall and into the space of disse?

Back 60

Plasma only, cells and other larger structures cannot pass.

Front 61

What supports the sinusoid epithelium?

Back 61

A network of reticular fibers.

Front 62

What sort of cells do the lumens of sinusoids often contain and where are they derived from?

Back 62

Large branched phagocytic cells (Kupffer cells), derived from the mononuclear phagocyte line.

Front 63

What do Kupffer cells do?

Back 63

These cells phagocytose damaged red blood cells and plasma debri.

Front 64

Describe what liver hepatocyts do to the end-products of absorption. WHere do these endproducts come from? What are they stored as and when are they released?

Back 64

Hepatocytes metabolize the end products of absorption from the ailementary canal, stores these as cellular inclusions and releases them into sinusoids in response to hormonal or neural signals.

Front 65

Describe the shape/ organization of hepatocytes.

Back 65

Large polygonal shaped cells which are packed together to form thin plates or cords of the liver parenchyma.

Front 66

Descibe the nucleus of hepatocytes.

Back 66

Bi nucleated occasionally and of variable size.

Front 67

How many mitochondria do hepatocytes have?

Back 67

Numerous mitochondria.

Front 68

Describe the RER of liver hepatocytes.

Back 68

Abundant due to much protein synthesis

Front 69

Describe the golgi of hepatocytes.

Back 69

Prominent

Front 70

Describe the quantities of peroxisomes, lysosomes and endosomes in hepatocytes.

Back 70

Numerous

Front 71

Hepatocytes contain lipid droplets (VLDL) when are they increased?

Back 71

After a fatty meal.

Front 72

What is the SER of the hepatocytes responsible for?

Back 72

Drug metabolism and detox.

Front 73

What happens to the SER of hepatocytes when lipid-soluble toxin levels rises?

Back 73

Number increases.

Front 74

What does the lumen of SER of hepatocytes contain?

Back 74

Microsomal mixed-function oxidase system".

Front 75

What are the 3 most common methods of drug inactivation and detoxifaction? Where are these peformed?

Back 75

In hepatocyte SER, methylation, conjugation, oxidation.

Front 76

What 2 types of surfaces do polygonal hepatocytes within hepatic plates contain?

Back 76

Those which border other hepatocytes (lateral domain)

And those that border the sinusoids (sinusoidal domain).

Front 77

What are the bile canaliculus? What domain are they a part of?

Back 77

The lateral domain contains a tubular space between hepatocytes that form the bile canaliculus which are initial portions of the bile duct system.

Front 78

What is the lateral domain formed from?

Back 78

Solely from the hepatocyte membranes.

Front 79

What surrounds membranes adjacent to the canaliculi in the lateral domain of hepatocytes? What do they do?

Back 79

The membranes adjacent to the canaliculi are surrounded by tight junctions which isolate the bile space from the extracellular space.

Front 80

From what surface do microvilli protrude from the canaliculi of hepatocytes in the lateral domain?

Back 80

Short microvilli.

Front 81

What do bile caniculi form relative to hepatocytes? What do they connect with? Where do they converge?

Back 81

Bile canaliculi form a ring around hepatocytes and connect with those of adjacent hepatocytes to fmorm a complex branched network which converges on the portal region of the lobule.

Front 82

What do bile canaliculi empty into? In what region? Where do they lead?

Back 82

Bile canaliculi empty into bile ductals (Canals of Herring) in the portal region which lead to the portal bile ducts. These lead then do larger ducts wich eventually fuse with the left and right hepatic ducts.

Front 83

What type of epithelium lines bile ductules and bile ducts?

Back 83

Cuboidal epithelium.

Front 84

What seperates the sinusoid epithelia from the hepatocytes in the sinusoidal domain?

Back 84

The space of Disse.

Front 85

What enzymes are particularly active in the sinusoidal domain of the liver? Why?

Back 85

Na+/K+ ATPase and adenylate cyclase wich facilitate membrane transport.

Front 86

What is the major secretion of the liver?

Back 86

Bile

Front 87

What sort of digestive enzymes does bile contain?

Back 87

NO digestive enzymes.

Front 88

What functions does bile have? (3)

Back 88

Diluting and neutralizing acid chyme in the intestines and adjucting the intestinal pH to appropriate levels for pancreatic enzymes to function. Also to emulsify fat.

Front 89

What are the major compounds of bile?

Back 89

Bile salts (Taurocholate, glycocholate), bilirubin, electrolytes, cholesterol, phospholipids, lecithin, IgA

Front 90

Where do the bile salts in bile come from?

Back 90

80% reabsorbed from small intestine
10% synthesized

Front 91

What is bilirubin?

Back 91

Yellowish green toxic product of hemoglobin degradation.

Front 92

Describe the shape/location of the gall bladder.

Back 92

The gall bladder is a hollow pear-shaped organ attached to the posterior-inferior surface of the liver.

Front 93

What is the major function of the gall bladder?

Back 93

Store, concentrate and release bile.

Front 94

Is the gallbladder a gland?

Back 94

NO

Front 95

What are the 5 layers of the gallbladder wall? (from interior to exterior) Be sure to mention what they are composed of (cell type etc.)

Back 95

1. Simple columnar epithelium composed of clear and brush cells.
2. Lamina propria composed of vascularized loose CT
3. Muscularis externa composed of smooth muscle of mixed orientation
4. A layer of perimuscular CT
5. A thin outer simple squamous epithelium (serosa)

Front 96

How does bile reach the gall bladder from the liver?

Back 96

Via the common hepatic duct.

Front 97

What are the 3 functions of bile?

Back 97

Emulsification of fat
Excretion of waste products from dead RBCs
Excretion of excess choloesterol synthesized in the liver.

Front 98

How is bile concentrated in the gall bladder?

Back 98

Removal of water and ions (concentrated 5-10 times)

Front 99

How much bile does the gallbladder release into the liver every day? What triggers its release?

Back 99

Up to 1200 mL of bile. Occurs in response to contraction of the gall bladder's smooth muslce layer.

Front 100

What is the signal for gallbladder contraction? Where is this produced?

Back 100

The signal is the hormone cholecystokinin-pancreozymin produced by the enteroendocrine cells of intestinal epithelium.

Front 101

What controls the flow of bile? At what junction?

Back 101

The flow of bile is controlled by the sphincter choledochus, at the junction of the common bile duct and the duodenum.

Front 102

What causes the duodenum and bile duct to releax?

Back 102

CCK (cholecystokinin)

Front 103

What is the junction of the common bile duct and the duodenum called?

Back 103

Ampulla of Vater.

Front 104

What forms gallstones? Where do they frequenly lodge?

Back 104

Cholesterol precipitating, fequently lodge in the cystic of common hepatic ducts.

Front 105

Describe the type of gland the pancreas is and where it is.

Back 105

An oblong tubuloacinar gland that nestles within the curvature of the duodenum.

Front 106

What are the 4 regions of the pancreas?

Back 106

The Uncinate process, head, body and tail.

Front 107

What drains the secretions of the pancreas?

Back 107

The pancreatic duct.

Front 108

What envelopes the pancreas? What does it form?

Back 108

A thin connective tissue capsule which forms delicate septae within the parenchyma to divide the organ into lobules.

Front 109

What takes on the exocrine function of the pancreas? How about the endocrine?

Back 109

Pancreatic acini, Islets of Langerhans.

Front 110

Describe Acini (morphology, cell types, components).

Back 110

Round to oval shaped secretory units composed of 40-50 pyramidal shaped acinar cells which form secretory component and 3-4 centrally locaed low cuboidal centroacinar cells which form the beginnings of the duct system.

Front 111

What do centroacinar cells of the pancreas lead to?

Back 111

The initial portion of the duct system or intercalated ducts.

Front 112

Intercalated ducts from neighboring acini join to form larger INTRAlobular ducts which are composed of what type of cells?

Back 112

Simple cuboidal-columnar cells.

Front 113

Intralogular ducts from several lobules converge to form larger INTERlobular ducts which are composed of what type of cells?

Back 113

Low columnar epithelium.

Front 114

What do the interlobular ducts empty into?

Back 114

The main pancreatic duct.

Front 115

Describe pancreatic acinar cells shape. WHy are they shaped this way?

Back 115

Pyramidal-shaped cells with an ultrastucture typical of a cell polarized for protein synthesis and secretion. These cells are polarized somewhat.

Front 116

Describe the basal region of pancreatic acinar cells. (4)

Back 116

Their basal region rests on a basement membrane. It contais a round nucleus, an extremely well developed RER with numerous basophilic polysomes and numerous mitochondria.

Front 117

Describe the apical region of pancratic acinar cells. (4)

Back 117

Numerous secretory zymogen granules whose number fluctuates with the state of fasting
Well developed golgi
Numerous microvilli on the luminal surface
Tight/Adhereing/desmosomes/gap junctions connect adjacent cells and isolate the lumen form the intercellular space.

Front 118

What activates proenzymes in the duodenum?

Back 118

Trypsin.

Front 119

In what form are the enzymes of the pancreas released?

Back 119

Inactive proenzymes.

Front 120

What prevents autodigestion of the pancreas? Where do these come from?

Back 120

It is protected from premature activation by a trypsin inhibitor secreted by the acinar cells.

Front 121

Why are inflammatory diseases of the pancreas (pancreatitis) so dangerous?

Back 121

It can result in the lysis of the acinar cells and subsequent release of active digestive enzymes into the abdominal cavity causing serious organ damage.

Front 122

What occupies the lumen of each acinus? WHat do these represent?

Back 122

Centroacinar cells occupy the lumen of each acinus. They represent the initial portion of the intercalated ducts.

Front 123

Describe the physical appeareance of centroacinar cells.

Back 123

Small, stellate with a clear cytoplasm.

Front 124

What are centroacinar cells diagnostic for?

Back 124

The pancrease.

Front 125

What do centroacinar cells do?

Back 125

Secrete bicarbonate ions which maintain duodenal pH appropriate for enzyme function.

Front 126

What is trypsinogen for, what secretes it?

Back 126

Proteolysis, acinar

Front 127

What is chymotrypsinogen for, what secretes it?

Back 127

Proteolysis, acinar

Front 128

What is procarboxypepsidase for, what secretes it?

Back 128

Proteolysis, acinar

Front 129

What is pancreatic amylase for, what secretes it?

Back 129

Hydrolyzes starch and glycogen

Front 130

What is pancreatic lipase for, what secretes it?

Back 130

Hydrolyzes fats

Front 131

What secreates ribonuclease, deoxyribonuclease and cholseterol esterase?

Back 131

Acinar cells

Front 132

What regulates acinar cell enzyme secretion? What produces this?

Back 132

IT is regulated by the hormone Cholecystokinin (CCK) which is produced in the epithelium of the duodenum.

Front 133

Where are the receptors for CCK on acinar cells located?

Back 133

The basal surface.

Front 134

What regulates the secretion of centroacinar cells? What procduces this?

Back 134

The secretion of centroacinar cells is regulated by levels of the hormone secretin produced by the duodenal epithelium.

Front 135

What are pancratic islets of langerhans? What is their appearance? WHere are they found?

Back 135

They ae multihormonal micro-organs in the form of ovoid groups of clear endocrine cells scattered throughout the exocrine pancreas. They ar most numerous in the tail region of the pancreas.

Front 136

What are the 3 effects of liver failure?

Back 136

Reduced protein synthesis
Reduced metabolic detoxification
Decreased bile secretion

Front 137

What does reduced protein synthesis of the liver lead to?

Back 137

Decreased albumin synthesis with decreased osmotic pressure in the blood causing edema.

Also increased spontaneous internal bleeding due to reduced synthesis of clotting factor.

Front 138

What is the result of reduced metabolic detoxification in the liver? What pathological state can this lead to?

Back 138

Increased plasma levels of biological toxis leading to hepatic coma.

Front 139

What does decreased bile secretion lead to? (pathological state).

Back 139

Bile accumulation in the liver and plasma manifested as a yellowish discoloration of the skin = jaundice.

Front 140

What is acute hepatic failure due to? What inflammes?

Back 140

Viral infection which results in inflammation of the hepatic plates (hepatitis)

Front 141

What does chronic progressive liver disease result from (cirrhosis)?

Back 141

Chronic alcohol or drug abuse, chronic viral hepatitis.

Front 142

How does viral hepatitis damage the liver? What does this damage result in?

Back 142

Destruction of hepatic plates and sinusoids which are replaced by fibrous CT scars. Thus the reorganized, damaged lobule is altered with reduced synthesis, secretion and blood flow.