Physiology of the pancreas

Question 1

Where is the R lobe of the pancreas

Answer 1

mesoduodenum

Question 2

where is the L lobe of the pancreas

Answer 2

leaf of greater omentum

Question 3

where are the 2 pancreatic ducts in the dog

Answer 3

• Smallest, the pancreatic duct, opens with the bile
duct on the major duodenal papilla.
• Accessory pancreatic duct is larger and opens on the minor duodenal papilla.

Question 4

exocrine glands

Answer 4

secrete substances on an epithelial surface via a duct.

Question 5

endocrine glands

Answer 5

are ductless and secrete their substances (hormones) directly into the blood.

Question 6

is the pancreas an endocrine, exocrine gland, or both

Answer 6

both

Question 7

exocrine functions of the pancreas

Answer 7

critical for digestion

acini of pancreas secrete compounds (enzymes) to aid in further digestion of acidic chyme from stomach (HCl)

Centroacinar cells and duct cells secrete Bicarbonate

Question 8

acini of the pancreas

Answer 8

secrete enzymes to help digest chyme

Question 9

Centroacinar cells and duct cells

Answer 9

secrete Bicarbonate

Question 10

release of enzymes from acini

Answer 10

Pancreatic enzymes are released from the acini in granules that are in the pre-enzymatic form (proenzyme).
• An enzyme released by the duodenum activates them – enterokinase, and the enzymes are ready to work.
• The released bicarbonate allows the pH to be maintained at an ideal level for the enzymes to function.

Question 11

pancreatic amylase

Answer 11

reduces large polysaccharides to smaller units

• Breaks down starches to maltose, glucose, etc. Small intestinal enzymes can further reduce to glucose, which can be directly absorbed.

Question 12

Trypsin, chymotrypsin

Answer 12

enzymes which reduce proteins to amino acid subunits, which can be absorbed.

Question 13

pancreatic lipase

Answer 13

digests lipids→large triglycerides reduced to fatty acids and monoglycerides.

• Bile helps to emulsify the fats, allowing larger surface area for the enzymes to work with.

Question 14

Ribonucleases and deoxyribonucleases

Answer 14

digest nucleic acids – reduces to the nitrogenous bases.

Question 15

phases of pancreatic secretion

Answer 15

• Sight and smell of food leads to the a central vagal response called the cephalic phase.
• Distension of the stomach – gastric phase – stimulates pancreatic secretions.
• (These get the small intestine ‘ready’ for the oncoming food.)
• When food enters from the stomach, the duodenum distends and the intestinal phase begins.

Question 16

cephalic phase of pancreatic secretion

Answer 16

Sight and smell of food leads to the a central vagal response called

Question 17

gastric phase of pancreatic secretion

Answer 17

Distension of the stomach stimulates pancreatic secretions.

Question 18

intestinal phase of pancreatic secretion

Answer 18

When food enters from the stomach, the duodenum distends and the intestinal phase begins.

Question 19

pancreas functions

Answer 19

assists in digesting all major food compounds

buffers pH of small intestine where enzymes are most efficient 6.8

Question 20

pancreatic intrinsic factor

Answer 20

required for b12 absorption

used in erythropoiesis, cellular metabolism, energy production, DNA creation and regulation, fatty acid synthesis, etc.

Question 21

pancreatitis mechanism

Answer 21

increased fat ingestion

zymogens not normally activated until they reach small intestine

in pancreatitis, lysosomes and zymogens in pancreas cells can fuse, releasing digestive enzymes into the pancreas itself

damage of pancreas can be life threatening

Question 22

islets of Langerhans (pancreatic islets)

Answer 22

make up 1-2% of pancreas but receive 10-15% of blood flow

4 cell types- alpha, beta (most numerous), D, F

Question 23

what do alpha cells produce

Answer 23

glucogon

Question 24

what do beta cells produce

Answer 24

insulin

Question 25

what does insulin do?

Answer 25

prevent hyperglycemia

• promotes storage of all 3 nutrients (esp glucose)
• first, gets digested/absorbed nutrients out of blood, into cells
• then, promotes synthesis of storage form of each nutrient.
• so, dominates in “fed” state

Question 26

What does glucagon do?

Answer 26

Raise BG, keep adequate glucose available in blood for cellular function.

promotes utilization of all 3 nutrients (esp. glucose):
• so, promotes catabolism of storage form of each major nutrient
• gets digested/absorbed nutrients out of cells, and into blood • so, dominates in “fasting” state

Question 27

what is the brains preferred energy source?

Answer 27

glucose