9.2 Accessory Organs of Digestion Flashcards
What are the 4 accessory digestive organs?
pancreas, liver, gall bladder, salivary glands
Where is the pancreas?
lies deep in the abdominal cavity, resting on the posterior abdominal wall
What is the pancreas?
an elongated and somewhat flattened organ that has both endocrine and exocrine functions
What happens in the exocrine function of the pancreas?
most pancreatic cells produce pancreatic juice, which contains sodium bicarbonate to help neutralize the stomach acid, and digestive enzymes for all types of food
What does the pancreas do as an endocrine gland?
secretes insulin and glucagon
What is glucagon?
hormone that help keep the blood glucose level within normal limits?
What are the pancreatic islets?
clusters of at least 3 typed of endocrine cells: alpha, beta, delta
What do alpha cells do?
produce glucagon
What do beta cells do?
produce insulin
What do delta cells do?
produce somatostatin
What are insulin and glucagon important for?
regulating the blood glucose level
When is insulin secreted?
when the blood glucose level is high, which usually occurs just after eating
What does insulin stimulate?
the uptake of glucose occurs just after eating, especially liver cells, muscle cells, and adipose tissue cells
What is glucose stored as in liver and muscle cells?
glycogen
What does the breakdown of glucose in the muscle cells do?
supplies energy for protein metabolism
What does the breakdown of glucose in fat cells do?
supplies glycerol for the formation of fat
Where does glucagon come from?
secreted from the pancreas, usually before eating, when the blood glucose level is low
What are the major target tissues of glucagon?
liver and adipose (fat) tissue
What does glucagon stimulate?
stimulates the liver to break down glycogen to glucose
What is also used as energy sources by the liver?
fat and protein, thus sparing glucose
What do adipose tissue cells do?
break down fat to glycerol and fatty acids, then the liver takes these up and uses them as substrates for glucose formation
What lowers the blood glucose level?
insulin
What raises the blood glucose level?
glucagon
What is somatostatin?
a growth hormone inhibiting hormone