Classification Of Exocrine Glands Flashcards
Describe the structure of compound glands starting from the main duct:
Lobar -> Interlobar -> Intralobar -> Striated -> Intercalated -> Acinus w/basement membrane and myoepithelia
The salivary glands are classified as what?
Tubuloalveolar glands
What does saliva contain in it?
What produces the saliva?
What controls it?
Proteins, mucins, ions, water, IgA
Submandibular gland (70%) and parotid gland (25%)
ANS
Where are intercalated ducts longest?
In the parotid gland
Where are striated ducts well developed?
What is their function?
Submandibular and parotid glands
Transport of water and ions
What does the parotid gland make?
IgA and serous acini
What does the sublingual gland make?
Mixed serous and mucus, but MOSTLY mucus
What does the submandibular gland make ?
Mixed serous and mucus
Serous demilunes
Saliva has a protective feature via what 3 mechanisms?
Lysozyme attack bacterial walls
Lactoferrin chelates iron needed for bacterial growth
IgA neutralizes bacteria
What enzymes does saliva rely on?
Amylase for carbs
Lingual lipase for lipids
What enzymes are in the parotid gland?
Amylase, peroxidase, lysozyme
What kind of antimicrobial proteins does the parotid gland have?
Proline-rich
Histatins
Cystatins
Statherin
What do the serous cells of the submandibular gland produce?
Mucous cells?
Salivary amylase
Help in lubrication of food
What is the endocrine component of the pancreas?
Main function?
Islet of Langerhans, 2% of volume
Regulation of glucose metabolism
What is the primary target of rabies and mumps
What are 2 complications of mumps?
What can these complications cause?
Parotid gland
Orchitis and meningitis
Orchitis can cause sterility
What is the functional unit of the exocrine pancreas?
What does it lack?
Acinus
Striated ducts and myoepithelial cells
What are centroacinar cells?
Continuous with the low cuboidal epithelial lining of the intercalated duct
What kind of cells are spindle-shaped in the pancreas?
What do they secrete?
Centroacinar
Bicarbonate when stimulated by secretin
Also mucin
What binds to acinar cell receptors and stimualates release of zymogen?
CCK
Epithelial cells of the intercalated duct secrete what?
What acts on these cells?
Water and bicarbonate ions
Secretin
How does auto digestion of pancreatic acini occur?
Premature activation of pancreatic enzymes OR the inactivation of trypsin inhibitor
What are the clinical features of acute pancreatitis?
Etiology?
Severe abdominal pain, nausea, vomiting, rapid elevation of lipase and amylase
Heavy meals or excessive alcohol ingestion
What supplies blood to the liver?
Portal vein and hepatic vein
Where does portal and hepatic blood mix?
Where does it converge?
Sinusoids
Ventral venule of the liver lobule
Where do central veins converge?
Sublobular veins
What makes up the hepatic lobule?
Anastomosing plates of hepatocytes limiting blood sinusoidal spaces
Central venule collects sinusoidal blood
What are the 3 ways to classify the hepatic lobule?
Classic hepatic lobule
Portal lobule based on bile drainage pathway
Liver Acinus based on the zone of gradient distribution
Describe the class is hepatic lobule
Hexagonal
Surrounds a central vein
Portal triads at angles
Describe a portal lobule
Triangular arrangement
Center of triangle is bile duct collecting from 3 lobules
Angles are the central veins of 3 hepatic lobules
Describe the liver Acinus arrangement
Based on oxygen gradient of venous sinusoids
Divided into 3 zones based on blood supply to hepatocytes
Describe the flow of blood through a hepatocytes
Portal vein and hepatic a. -> sinusoids -> central venule -> sublobar veins -> IVC
What is the lobule structure?
Hepatocytes arranged in thin layers radiate from central canal vein to the periphery
What is found within sinusoids??
Kupffer cells that recycle old RBCs
Where is the space of Disse located?
Between hepatocytes and fenestrated epithelium
What can extend into the space of Disse allowing proteins to be absorbed by hepatocytes?
Micro villi
What do Ito (stellate) cells do?
Where are they located?
Storage sites for fat and Vit A
Intervals within the space of Disse
Which direction does bile flow?
What produces it?
Opposite of blood
Hepatocytes
How is bile transported?
To where?
Bile canaliculi
Canal of Herin(cholangiole) and then into the bile duct and portal space
What does the basolateral domain of hepatocytes do?
What kind of function?
Absorption of blood-borne substances and secretion of plasma proteins
Endocrine
The hepatocytes contain SER, what is their function?
Synthesis of cholesterol and bile salts
Conjugation of bilirubin, steroids, drugs
Breakdown of glycogen into glucose
Detoxification of lipid-soluble drugs
What does the RER and Golgi of hepatocytes do?
Synthesis and glycosylation of secretory proteins
What are prominent in hepatocytes?
Peroxisomes that generate hydrogen peroxidase
What are the functions of bile?
Excretion of cholesterol, phospholipids, bile salts
Fat emulsification
Transports IgA to intestinal mucosa and inhibits bacterial growth
Where does most bilirubin originate?
What happens when bilirubin reaches hepatic sinusoids?
Senescent RBCs destroyed by spleen and macrophages
Albumin detaches and bilirubin is internalized
What role do hepatocytes play in alcoholism?
Long-term consequences?
Metabolism of ethanol
Fatty liver, eventually hepatocellular carcinoma
What are the main functions of the gallbladder?
Storage, concentration, and release of bile
What kind of epithelium is the gallbladder?
What does the mucosa create?
Simple Columnar epithelia
deep clefts called Rokitansky-Aschoff crypts
What are the 2 types of gallstones?
Cholesterol stones - yellow-green (80%)
Pigment stones - smaller and darker, made of bilirubin
What are the 3 major types of glands with their subtypes?
Salivary (parotid, submandibular, sublingual)
Exocrine pancreas
Liver (gallbladder)
