Pancreas And Liver Flashcards
What does it mean to be an exocrine organ?
Secrete onto free surfaces usually through a duct (always performed by epithelial cells)
What are the three cellular mechanisms for exocrine secretion?
1-Merocrine
2-holocrine
3-apocrine
Exocytosis of a vesicle and membrane transport of salts and water such as in sweat and salivary glands is which mechanism of secretion?
Merocrine
Entire cell ruptures such as in sebaceous glands is which secretion mechanism?
Holocrine
Pinching off of the apical cell portion is which secretion mechanism?
Apocrine
What two structural types of glands are there?
Simple and compound (branches)
What are the two main types of secretory portions called?
- tubular (short long or coiled)
- acinar/alveolar (round or sacklike)
Colon crypts glands are what shape?
Simple tubular
Stomach glands are what shape?
Simple branches tubular
Sweat glands are what shape?
Simple coiled tubular
The urethral glands are what shape?
Simple acinar
Sebaceous glands are what shape?
Simple branched acinar
A proenzyme or inactive enzyme precursor is called what?
Zymogen (it is activated by removal of a peptide section)
Why is the zymogen form the one that is stored?
So that the pancreas isn’t damaged
What activates trypsinogen to be trypsin in the duodenal lumen?
Enterokinase
What makes the pancreas a mixed endocrine-exocrine organ?
Produces digestive enzymes as well as hormones
How much is secreted into the duodenum each day, stimulated by CCK and secretin?
1.5 L
What two major digestive proteins are secreted by the pancreas?
Trypsinogen and chymotrypsin
Cystic fibrosis can make the production of which enzymes difficult in the pancreas?
a-Amylase
Lipases
Elastase
Nucleases
What two things help keep enzymes inactive in the pancreas?
Low pH in acini
Trypsin inhibitor
What are he main exocrine cells of the pancreas?
Acinar cells
Centroacinar cells
They drain into intercalated ducts
What does the secretin stimulated HCO3 do in the ducts?
Hydrate, flush and alkanize secretions
What is another name for acinar cells?
Zymogenic cells
Simple cuboidal cells roughly the size of acini are characteristic of what type of duct?
Intralobulated ducts
Simple columnar cells found in CT is typical of what type of duct?
Interlobulated ducts
What does it mean to be an endocrine organ?
Secretes into the blood (performed by epithelial and nonepithelial)
What are the masses of endocrine cells of the pancreas called?
Islets of langerhans
What three things are characteristic of islet of langerhans cells?
1-polygonal shape
2-smaller
3-stains lighter than acinar cells
What are the three major cells in the islets of langerhans?
Alpha, beta, delta
What do alpha cells secrete?
Glucagon (make up 30%)
What do beta cells secrete?
Insulin (make up 65%)
What do delta cells secrete?
Somatostatin (make up about 4%) which inhibits alpha and beta cells
Activated zymogens that start auto digesting the pancreas is called what?
Acute pancreastitis
What type of cancer comprises 3% of cancers in the US, is more common in females, and has a poor prognosis?
Pancreatic carcinoma
Disruption in insulin signaling and loss of or malfunction of B cells leads to what?
Diabetes mellitus
What major blood proteins does he liver synthesize?
Albumin Transferrin Fibrinogen Prothrombin Angiotensinogen
Lipids and lipoproteins are synthesized where? Such as cholesterol, FA, LDL, VLDL
Liver
What 4 things does the liver store?
1-Glucose as glycogen
2-lipids as fat droplets
3-far soluble vitamins
4-iron
What are three other liver functions?
1-Modification rxns (redox, conjugation)
2-elimination (billirubin)
3-lipid digestion (exocrine function)
What two flows of blood are there?
1-Nutrient rich, oxygen poor portal vein (75%)
2-oxygen rich hepatic artery (25%)
The hepatic arterioles and the portal venule mix their blood in what space on their way to the central vein?
Sinusoid
What is characteristic of zone 1?
- Freshest blood
- biggest mitochondria
- most active glucoronidation
- most active endocytosis
- highest regeneration
What is characteristic of zone 3?
- Highest cytochrome p450 and redox rxn
- fat is deposited here
How can you recognize a hepatocyte?
- Large cuboidal shape
- large nucleus (sometimes double)
- lots of mitochondria
Fenestrated epithelial cells are found lining what hepatic space?
Sinusoids
What fills the space of disse/perisinusoidal space?
Plasma
What are kupffer cells?
Liver macrophages in sinusoidal lining that phagocytose old erythrocytes to free up heme and iron
What do hepatic stellate cells do?
Store fat and far soluble vitamins and are found in space of disse
What happens when myo fibroblasts are present?
- Region becomes capable of contraction and collagen synthesis
- fibrosis
- portal hypertension
What empty into canals of hering?
Bile canaliculi
What do hepatocytes secrete into?
Bile canaliculi
What type of epithelial is found in the gall bladder?
Simple columnar epithelium
What is bile?
Detergent that aids hydrolysis of fat allowing it to be absorbed
What is enterohepatic recirculation?
Bile recycling
What affect does CCK have on bile flow?
Stimulates it and induces contraction of smooth muscle to expel bile
What affect does secretin have on bile ducts?
Causes secretion of bicarbonate into the bile
Blockage of bile flow results in what?
Cholestasis
Yellowing of skin and other tissues are signs of what?
Liver problems, specifically called jaundice
What is gall bladder inflammation called?
Cholecystitis
