8. Exocrine secretions
• Almost all of the pancreas (95%) consists of
exocrine tissue
• The function of the exocrine pancreas is to
produce pancreatic juice containing about 20
enzymes that digest carbohydrates , proteins and
fats.
• The pancreas secretes 1500–3000 mL of isosmotic
alkaline (bicarbonate + water) fluid per day
9. Regulation of Pancreatic Secretion
• Stimulated by the parasympathetic system and inhibited
by the sympathetic system.
• Stimulation occurs when we see, smell or taste food, or
when the stomach wall is stretched.
• Gastric acid is the stimulus for the release of secretin from
the duodenum, which stimulates the secretion of water and
electrolytes from pancreatic ductal cells.
• Release of cholecystokinin (CCK) from the duodenum
and proximal jejunum is triggered by LCFA, certain
essential amino acids and gastric acid itself.
• CCK evokes an enzyme-rich secretion from acinar cells in
the pancreas.
10. REGULATION OF SECRETION
1. SECRETIN
food in
stomach
release of
stomach acid
into duodenum
release of secretin
into blood by
duodenal cells
secretion of
bicarbonate
by duct cells
alkaline pH
(ideal for
pancreatic enzymes)
2. PANCREOZYMIN (cholecystokinen)
amino acids and
fats in intestine
release of pancreozymin
by intestinal mucosa
into blood
relase of pancreatic enzymes
into the intestine
3. GASTRIN
food in stomach gastrin secretion
by stomach mucosa
release of pancreatic enzymes
into the intestine
4. AUTONOMIC INNERVATION (vagus nerve)
11. PANCREATIC SECRETIONS
1. PROTEASES (70%)
Endopeptidases (trypsin, chymotrypsin, elastases)
Exopeptidases (carboxypeptidases)
trypsinogen trypsin activates all other precursors
enterokinase
(duct walls)
2. NUCLEASES (DNAase, RNAase)
3. PANCREATIC AMYLASE (hydrolyse starch and glycogen)
4. PANCREATIC LIPASE (triglycerides fatty acids and glycerol)
12. Endocrine secretions
• Distributed throughout the gland are groups
of specialised cells called the pancreatic
islets (islets of langerhans).
• The islets have no ducts so the hormones
diffuse directly into the blood.
14. Beta cells
• Secret insulin
• Main anabolic hormone of the body
• Regulates the metabolism of carbohydrates,
fats and protein by promoting the
absorption of carbohydrates
• Glycogenesis , lipogenesis
• Defeciency : diabetes mellitus
15. Alpha cell (endocrine)
• Secrets glucagon
• Action opposite to insulin
• Catabolic hormone
• Rises when there is hypoglycemia
• Glycogenolysis and gluconeogenesis
16. Delta cells
• Secrets gastrin and somatostatin
• Gastrin stimulates secretion of gastric acid
by the parietal cells of the stomach and aids
in gastric motility
• Somatostatin = GH inhibiting hormone
Inhibits the release of numerous secondary
hormones.
Inhibits insulin and glucagon secretion.
17. F (PP) cells
• Pancreatic polypeptide
• Self-regulate pancreatic secretion activities
(endocrine and exocrine)
• Has effects on hepatic glycogen levels and
gastrointestinal secretions.
• Increased after a protein meal, fasting,
exercise, and acute hypoglycemia
• Decreased by somatostatin and intravenous
glucose
20. Pancreatits
• Inflammation
• Central , acute pain , mainly at supine
• Acute release of digestive enzymes
• Digestive enzymes of the pancreas damage
the tissue and structure of the pancreas.
• Enzymes do not reach the duodenum
Incomplete digestion of fatty acids
steatorrhoea
21. Cystic fibrosis
• CFTR protein is defective
• CFTR helps in HCO3- secretion
• Secretion of bicarbonate by duct cells is affected
blockage in the pancreatic ducts damage to
acinar and duct cells
• Increased risk of pancreatitis
• Rucurrent LRTI
• Bronchiectasis
Head is further sub devided into head proper and uncinate process
It is related anteriorly to the superior mesenteric vessels and posteriorly to the aorta.
Accessory pancreatic duct of santorini
Main duct of wirsung
Almost all of the pancreas (95%) consists of exocrine tissue that produces pancreatic enzymes for digestion. The remaining tissue consists of endocrine cells called islets of Langerhans. These clusters of cells look like grapes and produce hormones that regulate blood sugar and regulate pancreatic secretions.
tryptophan, phenylalanine, valine, methionine
Cystic fibrosis transmembrane conductance regulator (CFTR)
A zymogen, also called a proenzyme, is an inactive precursor of an enzyme. A zymogen requires a biochemical change for it to become an active enzyme.