Salivary Glands: Anatomy, Cells, and Ducts
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Questions and Answers

In mixed glands, what structural arrangement leads to the formation of serous demilunes?

  • Mucinous acini completely enveloped by serous acini.
  • Isolated clusters of serous acini scattered throughout the gland.
  • Uniform distribution of serous and mucous cells within the same acinus.
  • Serous cells forming a cap-like structure around the distal mucous cells. (correct)

Which of the following processes best describes the cellular mechanism involved in secretion from serous cells within mixed glands?

  • Continuous synthesis and release of secretions without granule formation.
  • Direct diffusion of secretory products across the cell membrane.
  • Secretion via the Golgi apparatus involving reverse pinocytosis.
  • Accumulation of secretory granules followed by exocytosis into the lumen. (correct)

Following exocytosis in serous cells, what happens to the granule membrane?

  • It is immediately degraded by lysosomes.
  • It is endocytosed back into the cell. (correct)
  • It remains embedded within the lumen.
  • It fuses permanently with the plasma membrane, increasing the cell surface area.

What type of gland are serous demilunes usually seen in?

<p>Mixed glands (A)</p> Signup and view all the answers

What is the role of myoepithelial cells?

<p>Contracting to aid secretion (A)</p> Signup and view all the answers

Which of the following correctly describes the blood supply to the liver?

<p>The hepatic portal vein carries deoxygenated blood with newly absorbed nutrients and possibly drugs, microbes or toxins absorbed from the GI Tract, while the hepatic artery carries oxygenated, nutrient-poor blood. (A)</p> Signup and view all the answers

What is the primary function of the acini cells in the pancreas?

<p>Synthesizing and secreting pancreatic juices containing digestive enzymes into the duodenum. (B)</p> Signup and view all the answers

Where do the hepatocytes receive blood from, and where do they drain into?

<p>Hepatocytes receive blood from both the hepatic portal vein and hepatic artery and later drain into the central vein. (A)</p> Signup and view all the answers

Which of the following is NOT a primary exocrine function of the liver?

<p>Synthesis of fibrinogen for blood clotting (A)</p> Signup and view all the answers

A patient is diagnosed with biliary atresia. Which stool characteristic would be MOST likely observed?

<p>Pale-colored stool due to lack of bile pigments (B)</p> Signup and view all the answers

Which of the following statements is correct regarding the drainage of blood from the liver?

<p>The liver is drained by the hepatic vein, which then flows back to the heart through the inferior vena cava. (B)</p> Signup and view all the answers

The Islets of Langerhans secrete hormones directly into the bloodstream. What percentage of the pancreas do they constitute?

<p>1% (C)</p> Signup and view all the answers

The liver performs both exocrine and endocrine functions. Which of the following pairs correctly matches a function to its classification?

<p>Exocrine: Bile secretion; Endocrine: Fibrinogen synthesis (B)</p> Signup and view all the answers

A liver biopsy reveals prominent septations and portal triads that are not consistently found at every corner of the lobule. This sample MOST likely originates from which species?

<p>Human (D)</p> Signup and view all the answers

What is the approximate daily production volume of bile secreted by the liver?

<p>1 L (A)</p> Signup and view all the answers

If the liver is unable to synthesize prothrombin, which of the following physiological processes would be MOST directly affected?

<p>Blood clotting (A)</p> Signup and view all the answers

Which of the following liver functions directly contributes to the characteristic brown color of normal stool?

<p>Production of bile pigments from hemoglobin breakdown (D)</p> Signup and view all the answers

How does the liver assist in the processing of drugs within the body?

<p>By making them water-soluble for easier excretion (D)</p> Signup and view all the answers

Which of the following best describes the path of pancreatic juices from the pancreas to the duodenum?

<p>Acinar cells → Main pancreatic duct → Greater duodenal papilla (C)</p> Signup and view all the answers

The hepatopancreatic ampulla (Ampulla of Vater) is formed by the merging of which two ducts?

<p>Main pancreatic duct and common bile duct (D)</p> Signup and view all the answers

Which cellular feature is most indicative of the exocrine function of pancreatic acinar cells?

<p>Apically located zymogenic granules (A)</p> Signup and view all the answers

What is the primary function of centroacinar cells in the pancreas?

<p>Secreting bicarbonate-rich fluid (B)</p> Signup and view all the answers

Which of the following describes the relationship between the accessory pancreatic duct and the main pancreatic duct?

<p>The accessory duct drains a small portion of the head and body, while the main duct drains the entire pancreas. (A)</p> Signup and view all the answers

If the greater duodenal papilla were blocked, which of the following secretions would be most directly affected?

<p>Both bile and pancreatic enzyme secretion (C)</p> Signup and view all the answers

A researcher is studying pancreatic secretions. They notice a cluster of cells with basally located nuclei, supranuclear Golgi zones, and apically located zymogen granules. Which cells are they most likely observing?

<p>acinar cells (A)</p> Signup and view all the answers

Damage to the lesser duodenal papilla would most likely affect the drainage from which part of the pancreas?

<p>head (D)</p> Signup and view all the answers

The gallbladder's mucosa is characterized by which of the following features, distinguishing it from the small intestine?

<p>Unsymmetrical/haphazard villi and an absence of goblet cells (C)</p> Signup and view all the answers

What is the primary function of the Heister's valves located within the cystic duct?

<p>To prevent premature release of bile into the intestines (B)</p> Signup and view all the answers

How does cholecystokinin influence the function of the gallbladder?

<p>It relaxes the valves within the cystic duct, facilitating bile flow. (D)</p> Signup and view all the answers

During a cholecystectomy, which of the following structures is of particular importance for a surgeon to identify and be aware of?

<p>The cystic artery (B)</p> Signup and view all the answers

Which layer(s) is/are present in the wall of the gallbladder?

<p>Mucosa, Muscle layer (B)</p> Signup and view all the answers

Which of the following best describes the type of epithelium that lines the gallbladder?

<p>Tall columnar epithelium with microvilli (B)</p> Signup and view all the answers

What histological feature is unique to the gallbladder compared to other parts of the gastrointestinal tract like the stomach?

<p>Absence of muscularis mucosa and submucosal layer (C)</p> Signup and view all the answers

What are Rokitansky-Aschoff sinuses?

<p>Infoldings in the mucosa that reach the muscle layer of the gallbladder (D)</p> Signup and view all the answers

Which of the following best describes the arrangement of smooth muscle in the muscularis externa?

<p>Random orientation of smooth muscle cells (fibers) (A)</p> Signup and view all the answers

What is the primary role of enteroendocrine cells in the intestine?

<p>Producing hormones that regulate gastrointestinal processes (A)</p> Signup and view all the answers

What is the correct order of bile flow from production to the descending portion of the duodenum?

<p>Hepatocyte → bile ductules → bile canaliculi → right and left hepatic ducts → common hepatic duct → cystic duct → common bile duct → duodenum (C)</p> Signup and view all the answers

Why might gallstones cause colicky abdominal pain?

<p>They obstruct the flow of bile, causing gallbladder distention and contraction. (B)</p> Signup and view all the answers

What prevents all bile from immediately entering the intestine after production?

<p>The Sphincters of Boyden and Oddi remains closed, directing bile towards the gallbladder for storage (A)</p> Signup and view all the answers

What triggers the relaxation of the sphincter of Oddi and the release of bile into the duodenum?

<p>The presence of ingested fats in the small intestine (C)</p> Signup and view all the answers

Based on the information provided, what is one key difference between the muscularis externa and muscularis mucosae in the GI tract?

<p>The muscularis externa has smooth muscle with irregular orientation, while the muscularis mucosae has distinct layers. (D)</p> Signup and view all the answers

A patient presents with colicky abdominal pain after eating a fatty meal. Imaging reveals distention of the gallbladder. Which of the following mechanisms is the most likely cause of the patient's symptoms?

<p>Obstruction of the cystic duct, leading to increased pressure within the gallbladder. (D)</p> Signup and view all the answers

Flashcards

Mixed glands

Glands that produce both mucous and serous secretions.

Serous demilunes

Half-moon shaped serous cells found around mucous acini in mixed glands.

Myoepithelial cells

Contractile cells that help expel glandular secretions.

Exocytosis

Process where secretory granules release contents to the lumen.

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Endocytosis

Process where a cell takes in substances by engulfing them.

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Exocrine Portion of Pancreas

Part of pancreas that secretes digestive enzymes through ducts.

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Endocrine Portion of Pancreas

Part of pancreas that secretes hormones directly into the bloodstream.

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Main Pancreatic Duct

Duct that carries pancreatic juices into the duodenum. Also called Wirsung duct.

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Accessory Pancreatic Duct

Smaller duct that drains part of the pancreas into the duodenum.

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Acinar Cells

Cells in the pancreas that produce digestive enzymes and secrete them into the lumen.

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Centroacinar Cells

Specific cells in the pancreas that line the lumen of the acini and secrete bicarbonate.

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Zymogenic Granules

Granules in acinar cells that contain enzymes for digestion.

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Bicarbonate Secretion

Bicarbonate added to pancreatic juices to neutralize acidity of the stomach contents.

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Liver

The heaviest gland in the body with both endocrine and exocrine functions.

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Exocrine Function

Function of the liver that synthesizes and secretes bile through ducts.

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Endocrine Function

Liver's function of secreting plasma proteins into the bloodstream.

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Bile Production

The liver secretes approximately 1 L of bile daily for digestion.

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Carbohydrate Storage

The liver stores carbohydrates in the form of glycogen.

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Bilirubin

A bile pigment from the breakdown of hemoglobin, gives stool its color.

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Acholic Stools

Pale stools resulting from a deficient biliary tree.

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Liver Functions

Includes bile production, carbohydrate storage, protein synthesis, and anticoagulant production.

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Enteroendocrine cells

Cells that produce hormones in the intestine.

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Basal lamina

Thin sheet of tissue under epithelial cells, providing support.

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Muscularis externa

Layer of smooth muscle responsible for GI tract contractions.

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Smooth muscle orientation

Irregular arrangement of muscle fibers in certain gut areas.

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Route of bile filling

Pathway for bile from liver to gallbladder.

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Sphincter of Oddi

Muscle controlling bile flow into the duodenum.

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Gallbladder distention

Swelling of the gallbladder due to bile obstruction.

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Colicky abdominal pain

Severe pain due to gallbladder contraction.

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Gallbladder

Pouch under the liver that stores bile.

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Cystic duct

Duct that connects the gallbladder to the common bile duct.

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Heister's valves

Spiral valves in the cystic duct that regulate bile flow.

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Cholecystokinin

Hormone that stimulates contraction of the gallbladder.

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Rokintansky-Aschoff sinuses

Infoldings in the gallbladder mucosa reaching the muscle layer.

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Tall columnar epithelium

Type of cells lining the gallbladder, aiding absorption.

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Absorptive epithelium

Type of epithelium that absorbs substances, like bile.

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Lack of goblet cells

Gallbladder lining does not have mucus-secreting cells.

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Hepatic Blood Supply

The liver receives blood from both the hepatic portal vein and hepatic artery.

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Hepatic Portal Vein (HPV)

Carries deoxygenated blood with nutrients and toxins from the GI tract to the liver.

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Hepatic Artery

Delivers oxygenated, nutrient-poor blood to the liver.

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Pancreatic Exocrine Function

99% of pancreatic cells are acini, secreting digestive enzymes into the duodenum through ducts.

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Pancreatic Endocrine Function

1% of pancreatic cells (islets of Langerhans) secrete hormones like insulin and glucagon into the bloodstream.

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Study Notes

Salivary Glands

  • Three main pairs: parotid, submandibular, and sublingual
  • Parotid gland: primarily serous acini, rich in amylase for carbohydrate digestion
  • Submandibular gland: mixed serous and mucous acini, contains serous demilunes
  • Sublingual gland: primarily mucous acini
  • All major salivary glands are encased in connective tissue capsules
  • Contain branching acini emptying into the oral cavity via ducts
  • Secrete about 90% of total saliva volume

Salivary Gland Cell Types

  • Serous cells: produce watery, protein-rich saliva, staining dark in H&E due to ribosomes
  • Mucous cells: produce thick, mucus-rich secretion, staining light in H&E
  • Seromucous cells: contain both serous and mucous components

Salivary Gland Duct System

  • Intercalated ducts: small, simple squamous or low cuboidal epithelium, difficult to see
  • Striated ducts: cuboidal to columnar epithelium, prominent striations near basement membrane due to mitochondria
  • Intralobular ducts and interlobular ducts: part of the excretory ducts, located in the connective tissue septa
  • Main excretory ducts: carry saliva from the glands into the oral cavity

Liver

  • Heaviest gland in the body
  • Processes drugs to make them water-soluble
  • Endocrine and exocrine functions
  • Exocrine: synthesizes and secretes bile for digestion
  • Endocrine: produces plasma proteins
  • Functional unit: hepatocyte-rich plates and sinusoid capillaries radiating from central veins

Pancreas

  • Mixed endocrine and exocrine gland
  • Exocrine: produces pancreatic juices (enzymes, bicarbonate)
  • Endocrine: produces hormones (insulin, glucagon) in the islets of Langerhans
  • Pancreatic juices: approximately 1200-1500 ml daily, alkaline nature, contains enzymes for carbohydrate, protein, and lipid digestion

Gallbladder

  • Pear-shaped, distensible sac
  • Stores and concentrates bile produced by the liver
  • Histological features: tall columnar epithelium, mucosal folds (Rokitansky-Aschoff sinuses), smooth muscle layer, connective tissue
  • Bile route from hepatocytes: bile canaliculi → bile ducts → cystic duct → gallbladder

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Description

Explore the anatomy of salivary glands, including the parotid, submandibular, and sublingual glands. Learn about serous, mucous, and seromucous cells along with the intercalated and striated duct systems and their functions in saliva production.

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