Human Digestive Tract Part 2 Flashcards
What are accessory organs?
organs that connect to the gastrointestinal tract but in which food does not enter
endocrine definition
secretion of hormones directly into bloodstream
exocrine definition
secretion of products from glands into ducts
The human pancreas contains both endocrine and exocrine areas
What are exocrine pancreatic cell examples? What do they secrete?
- acinar and duct cells
- make up 99% of pancreatic cells
- they secrete digestive enzymes and NAHCO3
How do the digestive enzymes and NaHDO3 get to the duodenum
through ducts
What are endocrine cells called?
Islets of Langerhans (alpha, beta, delta, F cells)
What do endocrine cells do? What percentage of pancreatic cells to they make up?
Endocrine cells secrete hormones directly into the bloodstream. They make up 1% of pancreatic cells
What is the shape of acinar cells?
truncated pyramid
How are acina cells arranged? How do they empty?
They are arranged in groups around a central duct. The central duct then empties into the pancreatic duct, which then empties into the duodenum.
What type digestive enzymes does the pancreas produce? What else does it produce?
enzymes that digest proteins, starches, and lipids. It also produces buffers that neutralize acid from the stomach
What enzymes does the pancreas produce that digest PROTEINS?
trypsin, chymotrypsin
What enzymes does the pancreas produce that digest STARCHES?
amylase
What enzymes does the pancreas produce that digest LIPIDS?
lipase
What do proteases do?
They degrade protein to amino acids
What do lipases do?
They degrade fats to fatty acids and glycerol
What do amylases do?
They degrade carbohydrates to glucose
What does the pancreatic duct do?
it carries pancreatic juice to duodenum of small intestine
What is a substrate?
a molecule that binds to an enzyme at the active site
What is an active site on an enzyme?
where an enzyme catalytic reaction occurs
Most enzymes are proteins. They all have a specific substrate. A catalyst is also component, it is not used up in the reaction.
What stimulate the pancreas to secrete enzymes?
hormones
What enzymes does the pancreas secrete?
secretin, cholecystokinin (CCK), acetylcholine
cholecystokinin is released from the duodenum by the presence of
dietary fat, amino acids, and hydrochloric acid
When is acetylcholine produced?
as a response to the sensory aspects of feeding and to the physical effects of chewing and swallowing
After the pepsin is diactivated by the hgiher pH in the duodenum, the proteins can be further digested by other proteases such as:
- trypsin
- chymotrypsin
- carboxypeptidase
- erapsin
What is a zymogen?
A zymogen is the inacter precursor of an enzyme. It requires activation for the enzyme to work.
What is the trypsin pathway?
- the pancreas secretes inactive trypsinogen
- Once in the duodenum, the enzyme is converted from trypsinogen to active trypsin
- the new trypsin further breaks down proteins.
- Lastly, the trypsin then activates other proteases and peptidases
What are the 5 functions of the liver?
- detoxification (alchohol and drugs)
- Bile production and drainage and the synthesis of blood protein
- Synthesis and storage of amino acids, proteins, vitamins and fats, glycogen
- blood glucose regulation
- blood circulation and filtration - removes toxic nitrogen group from amino acids and hemoglobin to form urea (pee)
BREAKS UP FATS?
What does the gall bladder do?
It only stores bile - that’s why you can have you gall bladder removed
What does the liver do in relation to the digestive system?
- it continually produces bile
- emulsifies fat in the small intestine
- physical digestion
- stored in gall bladder