Histology Flashcards
What is the basic secretory unit of salivary glands? What does it include (3)?
salivon - includes the acinus, intercalated duct, and excretory duct
How are salivary glands divided up?
CT capsule w/ septa that divide the gland into lobes (interlobar septa) and smaller lobules (interlobular septa)
Describe the histology of mucous acini. What type of product do they produce?
- cloudy looking cytoplasm; pale pink/white staining
- produce a thick glycoprotein-rich product
Describe the histology of serous acini. What type of product do they produce?
- clear-staining cytoplasm
- produces a water-based product
Describe the histology of mucoserous acini. What type of product do they produce?
- contain a core of mucous (black) cells surrounded by a serous demilune (yellow bonnet of serous cells)
What is the location and function of myoepthelial cells?
between epithelial cells and basal lamina; contract to move secretory products towards the excretory duct
Describe the pathway of saliva flow
acinus -> intercalated duct -> striated duct -> excretory duct
Describe the histology of parotid glands. What type of product do they make?
- intense hot pink staining; large amounts of adipose tissue, CN VII passes through it
- serous only
Describe the histology of sublingual glands. What type of product do they make?
- faint pink to white staining; lacks defined capsule but divided into lobules by CT
- mixed gland (serous and mucous) but predominantly mucous
What type of product do submandibular glands make?
Serous cells predominant but mucous cells are present
What can be found on mucous cells in submandibular glands?
serous Demilunes (bonnets) on top of mucous acini
What type of function is the majority of the pancreas associated with? Describe that component.
Exocrine is majority - synthesizes/secretes enzymes that are essential for digestion in intestines
What is found within pancreatic acinar cells? What do they produce?
centroacinar cells - duct cells; produce HCO3
What is the hallmark of pancreatic cells? What are pancreatic cells often confused with?
acinar cells stain intensely, centroacinar cells stain lightly; often confused w/ parotid gland
How would you differentiate between the pancreas and parotid gland?
pancreas has lightly stained pancreatic islets (endocrine) floating darkly stained exocrine cells
Name 4 types of pancreatic proenzymes located in pancreatic acinar cells?
- amylolytic enzymes (digest carbohydrates)
- lipases (digest lipids)
- trypsinogen and chymotrypsinogen (digest proteins)
- deoxyribonuclease and ribonuclease (digest nucleic acids)
What is pancreatitis? Causes and sx?
- premature activation of pancreatic enzymes (autodigestion of pancreatic gland following release)
- usually caused by trauma, heavy means, excessive alcohol ingestion, or biliary tract disease
- sx include severe ABD pain, N/V
What is chronic pancreatitis and its major cause?
- characterized by fibrosis and partial or total destruction of pancreatic tissue
- alcoholism is major cause
Describe the blood supply to the liver
- portal vein (75%) - deoxygenated blood from GI tract (carries nutrients)
- hepatic A. (25%) - oxygenated blood
- liver cells receive mixed blood
Describe blood flow through the liver
blood from hepatic A. and portal vein mix in sinusoids that flow in between hepatocyte cords -> flow towards central vein of lobule -> returns to IVC via hepatic veins
Describe the histology of hepatocytes?
large, polygonal cells w/ large spherical nuclei
Describe the flow of bile to the gallbladder
bile from hepatocytes drain into bile canaliculi located between adjacent hepatocytes -> drain towards right and left hepatic bile ducts -> hepatic duct -> common bile duct -> gallbladder
What is the perisinusoidal space of Disse?
separates hepatocytes from the blood sinusoidal space; site of material exchange
What is the periportal space of Mall?
located at edges of canals between stomal CT and hepatocyte chords; site of lymph flow
Describe a classic liver lobule
hepatocyte chords surrounding a central vein; bile duct, portal V, and hepatic A (portal triad) surrounding hepatocytes
What are hepatic sinusoids lined with?
thin discontinuous endothelium and a discontinuous basal lamina (allows for material exchange)
What are Kupffer cells?
specialized macrophages (monocyte derived) found along endothelial lining of hepatic sinusoids
What projects into the space of Disse and what is its function?
microvilli from hepatocytes; increases surface area available for material exchange
What does a portal lobule look at? Describe a portal lobule
- looks at bile production
- central axis is bile duct; ID portal triad -> draw imaginary line between 3 central veins -> portal lobule
What does a liver acinus look at? Describe a liver acinus
- looks at blood flow
- diamond shape of hepatocytes arranged around a short axis (2 portal triads between 2 adjacent classic lobules)
Describe the 3 zones of a liver acinus
- zone 1: most O2 and most toxins (most affected by high concentration of toxins)
- zone 2: intermediate
- zone 3: least O2 and least toxins (most affected in ischemic events
What is hereditary hemochromatosis?
increased iron absorption and accumulation in lysosomal hepatocytes; leads to cirrhosis and liver cancer
What is Wilson’s disease?
hereditary disorder of copper metabolism; excessive deposits of copper in liver and brain
What is steatohepatitis?
fatty liver accompanied by an inflammatory reaction
Describe how you contract Hepatitis A, B, and C
A: infections caused by spread through ingestion of contaminated food/water
B: via sexual contact and blood/serum transfer through shared needles
C: 90% through blood transfusion
Describe the histology of the gallbladder
highly folded mucosa w/ a simple columnar epithelium (w/ microvilli); muscular w/ bundles of muscle fibers oriented in all directions to facilitate emptying
Does the gallbladder have adventitia or serosa?
Adventitia where it lies against the liver, but serosa where exposed to the peritoneal cavity
What are Rokatansky-Aschoff sinuses?
deep diverticula of the gallbladder mucosa that can extend into muscular externa; bacteria can accumulate here and higher risk for gallstones
