Histology of Accessory Organs Flashcards
What is the flow of saliva?
acinus –> intercalated duct (low cuboidal epi) –> straited duct (simple cuboidal to columnar epi) –> excretory duct (simple cuboidal to pseudostrat columnar or stratified cuboidal)
What does mucous acini produce?
thick glycoprotein rich product
What does serous acini produce?
water based product
What is the structure of mucoserous acini?
core of mucous cells surrounded by serous Demilune
Where are myoepithelial cells found? What do they assist in?
located between epithelial cells and basal lamina
moving secretory products toward the excretory duct
What kind of acini does the parotid gland have?
serous
What are the cellular features of the parotid gland?
Pyramidal cells with basally located nucleus, prominent RER in basal region, secretory granules visible in apical region
What are the features of the sublingual gland?
Branched tubule-alveolar gland with serous and mucous cells (but predominatly mucous), lacks defined capsule but is divided by CT into small lobes, intercalated and striated ducts are poorly developed
What kind of cells does the submandibular gland have?
Mucous cell have acini that are capped by serous demilunes
Serous secretions controlled by myoepithelial cells
What is the job of the exocrine component of the pancreas? What is its functional unit?
synthesizes/secretes enzymes essential for digestion in intestine
Serous acinus which contrains acinar cells
Where are the intercalated ducts of the exocrine pancreas? What do they secrete?
within acinus cetroacinar cells, continuous with low cuboidal of intercalated
HCO3-, Na+ and H20
What is the role of pancreatic acinar cells?
Have apical domain of zymogen granules which have pancreatic proenzymes, adjust levels based on diet (high carb then amylase, high protein then proteases)
What is the role of the endocrine component of the pancreas?
synthesizes/secretes hormones (insulin and glucagon) into blood –> regulation of glucose, lipid, and protein metabolism
What do the islets cells of the pancreas produce?
alpha= glucagon
beta= insulin
gamma= somatostain
pp cells= pancreatic polypeptide
What encloses the liver?
thin CT capsule line with mesothelium of visceral peritoneum lacking where directly adheres to diaphragm
What is the job of hepatocytes?
Secrete bile mixture of H2O bile salts and pigments phospholipids
Drains into bile canaliculus, canal lined with cholangiocytes located btwn adjacent hepatocytes, canaliculi join to eventually contribute to biliary tree
What is the function of bile?
fat absorption, excretion, cholesterol, bilirubin, iron, copper
What are the functional units of the liver?
hepatic lobule= histo
portal= bile and exocrine function
liver acinus= blood flow and O2 content
What are hepatic lobules?
Organization of liver parenchyma, form irregular plates radiating from central vein which are supported by a stroma of reticular fibers, plates separated by sinusoids (discontinuous)
Does blood and bile flow in the same direction?
NO opposite
What do the peripheral angles of hepatic lobules contain?
portal triad in fibrous CT= venule branch of portal vein rich in nutrients low in O2, arterioles from hepatic a. which supply O2, and bile
What are hepatic sinusoids?
anastomosing capillaries that perfuse hepatocytes with portal and arterial blood
What are Kupffer cells?
stellate macrophages within endothelium of sinusoids, larger than endo cells, detect and phagocytose effete erythrocytes, distinguish hepatic sinusoids
What are stellate macrophages?
small lipid droplets that store Vitamin A and other fat soluble
Where is the perisinusodial space of Disse?
between hepatocytes and sinusoidal endothelium (discontinuous cap), creates a potential space for exchange of materials between blood and hepatocytes
What is the role of the perisinusodial space of Disse?
Facilitates uptake/release of nutrients, proteins, and potential toxins
Microvilli project into space, plasma fills and bathes microvilli, increase SA
What are bile canaliculi?
anastomosing network of channels formed by hepatocyte plates and end near portal triads
What eventually becomes the R and L hepatic ducts?
Canaliculi –> canals of Hering (composed of cuboidal epithelial cells, cholangiocytes) –> bile ductules –> merge and enlarge –> r and l hepatic ducts
What is a portal lobule?
Central axis s bile duct, outlines bile drainage pathway from adjacent lobules in same bile duct, draw imaginary lines btwn 3 central veins triangle
What is a liver acinus?
Diamond shape and occupies parts of adjacent classic lobules, hepatocytes arranged in concentric zones around short axis, based on O2 gradient along sinusoids of adjacent lobules
What are Rokitansky-Aschoff sinuses?
deep diverticula of mucosa that extend through muscularis externa, develop as result of hyperplasia and herniation of epithelial cells through muscularis externa, bacteria can accumulate –> chronic inflamm and risk of gallstones
Where does the gallbladder have adventitia? Serosa?
Against the liver
Exposed to peritoneal
What is the job of the gallbladder?
stores and concentrates bile, release it into duodenum after a meal
What kind of mucosa is in the gallbladder?
Highly folded with simple columnar epithelium overlying lamina propria
