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Questions and Answers
Which statement accurately describes the function of the main pancreatic duct?
Which statement accurately describes the function of the main pancreatic duct?
What are the characteristics of the islets of Langerhans?
What are the characteristics of the islets of Langerhans?
In the case of acute pancreatitis, which of the following processes does NOT occur?
In the case of acute pancreatitis, which of the following processes does NOT occur?
What type of cells produce insulin within the islets of Langerhans?
What type of cells produce insulin within the islets of Langerhans?
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Which condition is characterized by deficient insulin production or defective insulin receptors?
Which condition is characterized by deficient insulin production or defective insulin receptors?
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What is the primary cause of Verner-Morrison syndrome?
What is the primary cause of Verner-Morrison syndrome?
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Which characteristic distinguishes the endocrine portion of the pancreas from the parotid gland?
Which characteristic distinguishes the endocrine portion of the pancreas from the parotid gland?
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Which of the following is a common complication of uncontrolled diabetes mellitus?
Which of the following is a common complication of uncontrolled diabetes mellitus?
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What causes alcoholic cirrhosis in the liver?
What causes alcoholic cirrhosis in the liver?
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What is the role of penicillamine in Wilson's disease?
What is the role of penicillamine in Wilson's disease?
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Which of the following is NOT a feature of gallbladder epithelial cells?
Which of the following is NOT a feature of gallbladder epithelial cells?
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What type of gland is the exocrine pancreas classified as?
What type of gland is the exocrine pancreas classified as?
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What structural feature is observed in the gallbladder mucosa when distended?
What structural feature is observed in the gallbladder mucosa when distended?
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Which of the following is true about glycogen in hepatocytes?
Which of the following is true about glycogen in hepatocytes?
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What triggers the degeneration of hepatocytes in cirrhosis?
What triggers the degeneration of hepatocytes in cirrhosis?
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Which component of the pancreas is primarily responsible for producing digestive proenzymes?
Which component of the pancreas is primarily responsible for producing digestive proenzymes?
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What is a characteristic feature of Rokitansky-Aschoff sinuses?
What is a characteristic feature of Rokitansky-Aschoff sinuses?
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What structure divides the pancreas into distinctive lobules?
What structure divides the pancreas into distinctive lobules?
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Which type of gland is the pancreas classified as?
Which type of gland is the pancreas classified as?
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Which of the following cells are found in the intercalated ducts?
Which of the following cells are found in the intercalated ducts?
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What receptors are located on the basal plasmalemma of centroacinar cells?
What receptors are located on the basal plasmalemma of centroacinar cells?
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What feature characterizes the cytoplasm of acinar cells?
What feature characterizes the cytoplasm of acinar cells?
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What is a distinguishing feature of interlobular ducts?
What is a distinguishing feature of interlobular ducts?
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Which part of the pancreas does the main pancreatic duct lead to?
Which part of the pancreas does the main pancreatic duct lead to?
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What is the primary function of acinar cells in the pancreas?
What is the primary function of acinar cells in the pancreas?
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What is the primary function of the liver's hepatocytes?
What is the primary function of the liver's hepatocytes?
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Which of the following is NOT a component of the porta hepatis?
Which of the following is NOT a component of the porta hepatis?
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Which structure separates the limiting plate from the connective tissue of the portal areas in classical lobules?
Which structure separates the limiting plate from the connective tissue of the portal areas in classical lobules?
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What shape describes the classical liver lobule?
What shape describes the classical liver lobule?
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In the context of liver structure, what does the term 'acinus of Rappaport' specifically relate to?
In the context of liver structure, what does the term 'acinus of Rappaport' specifically relate to?
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What is the role of the portal vein in the liver's vascular supply?
What is the role of the portal vein in the liver's vascular supply?
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What changes occur in individuals who have consumed hepatotoxic substances, particularly in relation to liver zones?
What changes occur in individuals who have consumed hepatotoxic substances, particularly in relation to liver zones?
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Which of the following is the primary anatomical feature of the portal lobule?
Which of the following is the primary anatomical feature of the portal lobule?
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Which type of blood vessel provides initial distribution of blood into the liver from the hepatic artery?
Which type of blood vessel provides initial distribution of blood into the liver from the hepatic artery?
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What type of connective tissue surrounds the liver's Glisson's capsule?
What type of connective tissue surrounds the liver's Glisson's capsule?
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Which zone of the liver acinus is most susceptible to necrosis due to low oxygen levels?
Which zone of the liver acinus is most susceptible to necrosis due to low oxygen levels?
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What structure facilitates the exchange of materials between blood and hepatocytes?
What structure facilitates the exchange of materials between blood and hepatocytes?
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Which type of collagen fibers are primarily associated with the support of sinusoids?
Which type of collagen fibers are primarily associated with the support of sinusoids?
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What is the primary function of hepatic stellate cells (Ito cells)?
What is the primary function of hepatic stellate cells (Ito cells)?
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What role do Kupffer cells play in the liver?
What role do Kupffer cells play in the liver?
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Which statement about hepatocytes is true?
Which statement about hepatocytes is true?
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What structure prevents bile leakage in the lateral domains of hepatocytes?
What structure prevents bile leakage in the lateral domains of hepatocytes?
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Which feature of hepatocyte plasma membranes increases surface area for material exchange?
Which feature of hepatocyte plasma membranes increases surface area for material exchange?
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What is a consequence of long-term usage of barbiturates on hepatocytes?
What is a consequence of long-term usage of barbiturates on hepatocytes?
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Which cells are known as natural killer cells in the liver?
Which cells are known as natural killer cells in the liver?
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Flashcards
Liver Size
Liver Size
The liver weighs approximately 1500 grams.
Liver Function
Liver Function
The liver is both an endocrine and exocrine gland, converting harmful substances into harmless ones.
Glisson's Capsule
Glisson's Capsule
Dense irregular connective tissue surrounding the liver, loosely attached at the porta hepatis.
Porta Hepatis
Porta Hepatis
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Hepatic Artery
Hepatic Artery
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Portal Vein
Portal Vein
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Hepatic Sinusoids
Hepatic Sinusoids
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Classical Lobule
Classical Lobule
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Portal Lobule
Portal Lobule
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Hepatic Acinus
Hepatic Acinus
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Zone 3 Hepatocytes
Zone 3 Hepatocytes
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Perisinusoidal Space of Disse
Perisinusoidal Space of Disse
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Hepatic Stellate Cells (Ito cells)
Hepatic Stellate Cells (Ito cells)
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Bile Canaliculi
Bile Canaliculi
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Liver Acinus
Liver Acinus
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Hepatocyte Lateral Domains
Hepatocyte Lateral Domains
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Hepatocyte Sinusoidal Domains
Hepatocyte Sinusoidal Domains
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Hepatocyte Organelles
Hepatocyte Organelles
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SER Increase in Barbiturate Users
SER Increase in Barbiturate Users
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Barbiturates and Liver Injury
Barbiturates and Liver Injury
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Drug Tolerance & Liver
Drug Tolerance & Liver
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Liver's Role in Fat Storage
Liver's Role in Fat Storage
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Glycogen Granules
Glycogen Granules
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Cirrhosis: Liver Scarring
Cirrhosis: Liver Scarring
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Wilson's Disease: Copper Overload
Wilson's Disease: Copper Overload
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Gallbladder Epithelium
Gallbladder Epithelium
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Gallbladder Epithelial Cells: Energy Production
Gallbladder Epithelial Cells: Energy Production
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Rokitansky-Aschoff Sinuses
Rokitansky-Aschoff Sinuses
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Intercellular Spaces in Gallbladder
Intercellular Spaces in Gallbladder
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Gallbladder Lamina Propria
Gallbladder Lamina Propria
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What is the structural organization of the pancreas?
What is the structural organization of the pancreas?
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What is the role of centroacinar (CA) cells?
What is the role of centroacinar (CA) cells?
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What are acini and their role?
What are acini and their role?
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What is the role of CCK and ACh in pancreatic secretion?
What is the role of CCK and ACh in pancreatic secretion?
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What is the function of intercalated ducts?
What is the function of intercalated ducts?
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What is the difference between intralobular and interlobular ducts?
What is the difference between intralobular and interlobular ducts?
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What is the role of the main pancreatic duct?
What is the role of the main pancreatic duct?
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What is the function of secretin?
What is the function of secretin?
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Main Pancreatic Duct
Main Pancreatic Duct
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Interlobular Ducts
Interlobular Ducts
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Centroacinar Cells
Centroacinar Cells
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Acute Pancreatitis
Acute Pancreatitis
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Islets of Langerhans
Islets of Langerhans
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Beta Cells
Beta Cells
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Type 1 Diabetes
Type 1 Diabetes
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Verner-Morrison Syndrome
Verner-Morrison Syndrome
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Study Notes
Liver
- Approximately 1500g
- Largest gland
- Endocrine and exocrine (bile) functions in the same cell (hepatocyte)
- Converts noxious substances into nontoxic materials
General Hepatic Structure
- Covered by Glisson's capsule (dense irregular connective tissue)
- Loosely attached except at porta hepatis (blood & lymph vessels & bile ducts)
- Sparse connective tissue within Glisson's capsule
General Hepatic Structure & Vascular Supply
- Porta hepatis
- Left & right hepatic artery
- Portal vein (nutrients, iron-rich blood from spleen)
- Right and left hepatic ducts
- Hepatic veins
Blood Supply
- Hepatic artery → distributing arterioles → inlet arterioles
- Peribiliary capillary plexus around interlobular bile ducts
- Portal vein → larger distributing veins → smaller inlet venules
- Central vein: initial branch of hepatic vein
- Hepatocytes radiate from central vein & separated by hepatic sinusoids
Types of Liver Lobules
- Classical lobule
- Portal lobule
- Hepatic acinus (acinus of Rappaport)
Classical Lobule
- Closely packed classical lobules (hexagon-shaped)
- Boundaries can only be approximated
- 3 lobules contact portal areas (triads)
- Hepatic artery, portal vein, and bile duct
Portal Lobule
- All hepatocytes that deliver their bile to a particular bile duct constitute a portal lobule
- Triangular region
- Portal area at the center
- Imaginary straight lines connecting 3 central veins
Hepatic Acinus (Acinus of Rappaport)
- Based on blood flow from distributing arteriole
- Hepatocytes degenerate subsequent to toxic or hypoxic insults
- Ovoid to diamond-shaped lobule
- Zone 1, Zone 2, Zone 3
Hepatic Sinusoids & Hepatocyte Plates
- Plates of hepatocytes radiate from central vein toward periphery of classical lobule
- Spaces between plates: sinusoids
- Sinusoidal lining cells
- Gaps between lining cells
- Fenestrae in clusters: sieve plates
Kupffer cells in Sinusoids
- Endocytose particulate matter and cellular debris, defunct erythrocytes
Perisinusoidal Space of Disse
- Narrow space between a plate of hepatocytes and sinusoidal lining cells
- Microvilli of hepatocytes, exchange of materials between blood & hepatocytes
Perisinusoidal Space of Disse
- Type 3 collagen (reticular) fibers, supporting sinusoids
- Type 1 & 4 collagen fibers
- No basal lamina
- Nonmyelinated nerve fibers
Space of Disse
- Hepatic stellate cells (Ito cells): fat storing cells
- Store vitamin A
- Manufacture & release type 3 collagen
- Secrete growth factors
- Form fibrous connective tissue to replace damaged hepatocytes
- Pit cells
- Natural killer cells
Hepatic Ducts
- Bile canaliculi
- Canals of Hering (Cholangioles)
- Interlobular bile ducts
- Right & left hepatic ducts
Hepatocytes
- 5-12 sided polygonal cells
- 20-30 µm diameter
- Closely packed to form one or two cell-thick plates
- Show variations in their structural, histochemical & biochemical properties depending on their location within lobules
Domains of Hepatocyte Plasmalemma
- Lateral domains
- Formation of bile canaliculi
- Bile leakage prevented by tight junctions
- High levels of Na, K-ATPase activity & adenylate cyclase
- Gap junctions
Domains of Hepatocyte Plasmalemma
- Sinusoidal domains
- Microvilli projecting into space of Disse
- Increase surface area, facilitating exchange between hepatocyte and plasma in perisinusoidal space
- Mannose-6-phosphate receptors
- Na, K-ATPASE
- Adenylate cyclase
- Endocrine secretions of hepatocytes released & enter sinusoidal blood
- Material from blood transported into hepatocyte cytoplasm
Hepatocyte Organelles and Inclusions
- Manufacture primary bile
- Abundant free ribosomes, RER, Golgi
- 2000 mitochondria
- Rich in endosome, lysosome & peroxisome
- SER
- Certain drugs & toxins increase SER
Hepatocyte
- Lipid droplets (mostly VLDLs)
- Glycogen
- Electron-dense granules (20-30 nm in size)
- Abundant after eating, fewer after fasting
Acute Pancreatitis
- Pancreatic digestive enzymes become active within cytoplasm of acinar cells
- Often fatal
- Inflammatory reaction, necrosis of blood vessels, proteolysis of parenchyma, enzymatic destruction of adipose cells
Islets of Langerhans
- Scattered among acini
- Richly vascularized
- Spherical conglomeration of 3000 cells
- 1 million islets
- Greater number in tail
- Surrounded by reticular fibers
Cells of Islets
- 5 types:
- Beta
- Alpha
- Delta (D&D1)
- PP (pancreatic polypeptide-producing)
- G (gastrin-producing)
Differences from Parotid Gland
- Exocrine part similar in structure to parotid gland
- Absence of striated ducts
- Presence of islets of Langerhans
- Initial parts of ICDs penetrate lumens of acini
- Centroacinar cells (nuclei surrounded by pale cytoplasm)
Diabetes Mellitus
- Hyperglycemic metabolic disorder
- Lack of insulin production from B cells or defective insulin receptors
- If uncontrolled: circulatory disorders, renal failure, blindness, gangrene, stroke, myocardial infarct
Type 1 Diabetes
- Usually affects persons <20 years of age
- Polydipsia (constant thirst)
- Polyphagia (undiminished hunger)
- Polyuria (excessive urination)
Type 2 Diabetes
- Non-insulin-dependent diabetes
- The most common type
- Affects persons >40 years of age
Verner-Morrison Syndrome
- Explosive, watery diarrhea
- Hypokalemia
- Caused by excessive manufacture and release of VIP due to adenoma of D1 cells
- Frequently, tumors of D1 cells are malignant
Gallbladder
- Simple columnar epithelium
- Mucinogen
- Short microvilli
- Lamina propria
- Smooth muscle
- Serosa/adventitia
Gallbladder Epithelial Cells
- Basally positioned oval nuclei
- Short microvilli coated by glycocalyx (carb rich coat → acid barrier)
- Basal region rich in mitochondria, providing abundant energy for Na-K ATPase pump in basolateral membrane
- Deep diverticula called Rokitansky-Aschoff sinuses
Gallbladder Intercellular Spaces
- Feature associated with transport of fluid across epithelium
- Commonly seen in intestinal absorptive cells
Gallbladder Lamina Propria
- Loose connective tissue
- Elastic & collagen fibers
- Neck: simple tubuloalveolar glands (mucus)
Gallbladder Smooth Muscle Layer
- Mostly obliquely oriented fibers
- Others longitudinally oriented
- Adventitia attached to Glisson's capsule
- Nonattached surface invested by peritoneum
Extrahepatic Ducts
- Right hepatic duct
- Left hepatic duct
- Common hepatic duct
- Cystic duct
- Common bile duct
- Pancreatic duct
- Ampulla of Vater
Pancreas
- Posterior body wall deep to the peritoneum
- Four regions: Uncinate process, Head, Body, Tail
- 25 cm long, 5 cm wide, 1-2 cm thick, 150 g
Exocrine Pancreas
- Compound tubuloacinar gland
- Produces bicarbonate-rich fluid & digestive proenzymes (1200 ml/day)
- 40-50 acinar cells form a round to oval acinus
- Lumen occupied by 3-4 centroacinar cells (distinguishing characteristic, beginning of duct system)
- Surrounded by BL supported by reticular fibers
Acinar Cell
- Like a truncated pyramid
- Base positioned on BL, separating cell from CT
- Basally located round nucleus, surrounded by basophilic cytoplasm
- Apex faces the lumen
- Apex filled with zymogen granules, eosinophilic
- Number diminishes after meal
- Golgi region between nucleus and zymogen granules varies in size in inverse relation to zymogen granule concentration
- Base contains many parallel cisternae of GER (basophilic staining in LM)
- Golgi apparatus fluctuates in size (smaller when zymogen granules numerous, larger after granules release their content)
- Microvilli from apical surface
- Z. occludentes (tight junction) at an apicolparcian
Islets of Langerhans
- Lightly stained polygonal or rounded cells arranged in cords separated by a network of fenestrated capillaries.
- Both parenchymal cells & blood vessels are innervated by ANS.
Pancreatic Duct
- ICD (Intralobular ducts)
- Interlobular duct
- Main pancreatic duct
- Common bile duct
- Papilla of Vater
Intercalated Ducts
- Receive secretions from acini
- Flattened to cuboidal epithelium that extends up into the lumen of the acinus to form centroacinar cells
Intralobular Ducts
- Cuboidal epithelium
- Within lobules
- Receive secretions from intercalated ducts
Interlobular Ducts
- Between lobules, within the connective tissue septae
- Vary considerably in size
- Smaller forms have cuboidal epithelium
- Larger ducts have columnar epithelium
- Transmit secretions from intralobular ducts to major pancreatic duct
The Main Pancreatic Duct
- Receives secretion from interlobular ducts
- Penetrates through the wall of duodenum
- Joins the bile duct prior to entering the intestine
Pancreas H&E
- Acinar cells
- Centroacinar cells
- Connective tissue
- Exocrine secretory tissue
Secretory Portion
- Basal cell membranes of acinar cells have receptors for CCK & ACh
- Abundance of basally located RER
- Rich supply of polysomes
- Numerous mitochondria
- Golgi well developed
Duct System
- Begins within center of acinus with terminus of intercalated ducts (ICD)
- Pale, low cuboidal centroacinar (CA) cells
- CA cells & ICDs have receptors on basal plasmalemma for secretin & possibly for ACh
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Description
Explore the intricate structure and vital functions of the liver in this quiz. From its role as the largest gland in the body to its unique vascular supply system, you'll test your knowledge on various liver lobules and their significance. Understand how hepatocytes work to detoxify substances within the liver.