pancreas Flashcards
pancreas produces 2 types of secretion
- endocrine; insulin, glucagon and gastrin, from islets of langerhans
- exocrine; enzymes, electrolytes and water, from pancreatic acini –> duodenum
which component of pancreas secretion is larger; endocrine or exocrine
exocrine
exocrine secretions of pancreas are digestive juice produced in _____ and discharged into: ______
- pancreatic acini
- discharged into proximal part of duodenum through one or two ducts
the exocrine secretion aka digestion juice contains digestive enzymes that break down
protein, carbohydrates and fats, as well as electrolytes and water
endocrine component of pancreas comprises the
pancreatic islets (of langerhans)
pancreatic islets (of langerhans)
clumps of cells that are scattered between the exocrine acini, and are the source of insulin, glucagon, and gastrin.
The islets are therefore really important in regulating the metabolism of carbohydrates, and maintaining blood sugar levels.
pancreas gross anatomy
diffuse, lobulated organ, pinkish-red, can sometimes be yellowish
location of pancreas
dorsal part of the abdominal cavity. It looks kind of like a salivary gland, although it is softer and more loosely knit
pancreas is closely associated w
closely associated with the duodenum, and the stomach
pancreas regarded as having a
body and 2 lobes
* works well for dogs but less for other species
The pancreas develops from two primordia that bud from the proximal part of the embryonic duodenum:
the dorsal and ventral primordia
the dorsal and ventral primordia buds later in development
merge
but we see evidence of dual origin of pancreas due to the duct system
A greater pancreatic duct commonly drains the part of the pancreas that arises from the
ventral primordium
greater pancreatic duct commonly opens into the duodenum w or just beside
bile duct
A lesser (accessory duct) emerges from the part of the pancreas that arises from
dorsal primordium
the lesser accessory duct enters duodenum on opposite aspect of gut at the
minor duodenal papilla
ventral and dorsal primordium turns into what duct and enter duodenums at what papilla
- ventral: pancreatic duct: major papilla
- dorsal: accessory duct: minor papilla
The duct system of the two lobes of the pancreas can
communicate within the gland
bile duct may join w pancreatic duct to enter duodenum or may enter
seperately
bile duct joins with pancreatic duct to enter duodenum in what species
horse, sheep and dog
bile duct enters duodenum seperate from pancreatic duct in what species
pig, cow
the bile duct passes oblqiuely through duodenal wall at major duodenal papilla, through the
sphincter of oddi
the pancreas is surrounded by a v thin connective tissue capsule that invaginates into the gland to form
septae; serve as scaffolding for large blood vessels, and divide pancreas into distinctive lobules
the pancreas is a compound ____ gland
acinous
the lobules of pancreas bound together by loose connective tissue containing
blood vessels, nerves, lymphatics and excretory ducts
pancreatic acini, what they do and how they are arranged
cells that synthesize and secrete digestive enzymes and arranged in grape-like clusters
each acinus consists of a single row of
pyramidal epithelial cells converging on central lumen
the acini release _____ containing enzyme precursors
zymogen granules
zymogen granules are more common during
fasting
zymogen
inactive substance (enzyme precursor) which is converted into an enzyme when activated by another enzyme
the lumen of each acinus is contunous with a small duct that is bounded by pale- staining
centroacinar cells
The lumen of each acinus is continuous with a small duct, that’s bounded by pale‐
staining centroacinar cells.
Tjese lead into an ever larger duct network of intercalated
then intralobular ducts which are lined by ______
the height of these epithelium ____ as duct becomes bigger and bigger
low columnar epithelium
increases
interlobular ducts epithelium
- ducts between lobes
- stratified cuboidal
intralobular lucts
- ducts within lobes
- large, low columnar epithelium
- contain goblet cells and small mucous glands so able to modify the secretion of the gland
islets of langerhans
small masses of endocrine cells scattered throughout the exocrine pancreas
islets of langerhans are demarcated (outlined by) by
reticular fibers
each pancreas contains about _____ islets of langerhans
one million
islet cells have a rich
blood and nerve supply
name 3 types of islet cells that can be seen with special stains
alpha, beta, delta
different adrenergic receptors for differing responses to catecholamines
alpha, beta and delta islet cells frequency and what they produce
- alpha: 20%, produce glucagon
- beta; 80%; produce insuline
- delta; 5%; produce somatostatin
- nongranular cells also present
pancreas recieves generous blood supply from
cranial and caudal pancreaticoduodenal arteries
cranial is a branch of coeliac artery
caudal is a branch from cranial mesenteric artery
veins of pancreas drain to enter the
hepatic portal vein
pancreas is supplied by both (nerves)
parasympathetic (vagal) and sympathetic
EPI
- exocrine pancreatic insufficiency
- lack of pancreatic exocrine secretion in SI
- most common cause in dogs is pancreatic acinar atrophy
- most common cause in cats in chronic pancreatitis
- lose weight despite good appetite
pancreatitis
- inflammation disrupts pancreas
- prancreatic granules (zymogens which are harmless in their inactive form) are prematurely activated and released internally, digesting the pancreas itself
- toxins released from this destruction of tissue are released into circulation and can cause body-wide inflammatory response
- sudden fatty meal is classic cause
Which of the following is an exocrine secretion of the pancreas?
A.
Insulin
B.
Glucagon
C.
Digestive enzymes
D.
Gastrin
Digestive enzymes
look at table of species lobe differences
Which part of the pancreas is in the mesoduodenum of the descending duodenum?
Right lobe
Which of the following statements regarding the development of the pancreatic ducts is CORRECT?
A.
The pancreas develops from two primordia that bud from the proximal part of the embryonic duodenum: the medial and ventral primordia. A greater pancreatic duct commonly drains the part of the pancreas that arises from the ventral primordium. A lesser (accessory duct) emerges from the part of the pancreas that arises from the medial primordium.
B.
The pancreas develops from two primordia that bud from the proximal part of the embryonic duodenum: the dorsal and ventral primordia. A greater pancreatic duct commonly drains the part of the pancreas that arises from the ventral primordium. A lesser (accessory duct) emerges from the part of the pancreas that arises from the dorsal primordium.
C.
The pancreas develops from two primordia that bud from the proximal part of the embryonic duodenum: the dorsal and ventral primordia. A greater pancreatic duct commonly drains the part of the pancreas that arises from the dorsal primordium. A lesser (accessory duct) emerges from the part of the pancreas that arises from the ventral primordium.
D.
A greater pancreatic duct commonly drains the part of the pancreas that arises from the ventral primordium. It opens into the duodenum together with, or just beside, the bile duct. Bile and pancreatic juice enter the duodenum together on the minor duodenal papilla.
B.
The pancreas develops from two primordia that bud from the proximal part of the embryonic duodenum: the dorsal and ventral primordia. A greater pancreatic duct commonly drains the part of the pancreas that arises from the ventral primordium. A lesser (accessory duct) emerges from the part of the pancreas that arises from the dorsal primordium.
Which of the following statements regarding acini is INCORRECT?
A.
Cells that synthesise and secrete digestive enzymes are arranged in grape-like clusters called acini
B.
Each acinus consists of a single row of pyramidal epithelial cells converging on the central lumen
C.
Pancreatic acini release zymogen granules containing enzyme precursors
D.
Pancreatic acini are small masses of endocrine cells
Pancreatic acini are small masses of endocrine cells
Which islet cells secrete insulin?
Beta (B) cells
Which islet cells secrete glucagon?
Alpha (A) cells
Which islet cells secrete somatostatin?
Delta (D) cells
