Digestive System Flashcards
What is the enteric nervous system?
Collection of about 100 million neurons, independent of the brain and spine, govern the function of the digestive tract and trigger peristalsis. Highly regulated by the autonomous nervous system. (But can function independently of the brain and the spine).
Which glands are not innervated by the parasympathetic nervous system?
Sweat glands
What hormones trigger feeling of thirst?
ADH and aldosterone
Which hormones trigger a feeling of hunger?
ghrelin and glucagon
Which hormones promote a feeling of satiety?
Leptin and cholecystokinin
Mastication
Chewing
What are the digestive enzymes present in the saliva? What do they do?
Salivary amylase (ptyalin) —> starch —>maltose and dextrin Lipase—> hydrolysis of lipids
What are the different parts of the esophagus? What are they made of?
Upper third —> skeletal muscles
Bottom third —> smooth muscles
Middle third —> mixed
What are the sphincters involved in ingestion?
Upper esophageal sphincter
Lower esophageal sphincter (cardiac sphincter)
Four anatomical divisions of the stomach?
1- fundus
2- body
3- pylorus
4- antrum
What kind of glands exist in each of the four regions of the stomach?
1- gastric glands in fundus and body
2- pyloric glands in pylorus and antrum
What is the nerve input for the gastric glands?
Vagus nerve
What are the cell types in gastric glands, what do each do?
1-mucous cells , produce bicarbonate rich mucous
2-chief cells produce pepsinogen
3- parietal cells produce HCL and intrinsic factor
What is the gastric juice?
Secretions of the chief cells and parietal cells
What is the function of the intrinsic factor? What kind of a molecule is it?
Glycoproteins: involved in the proper absorption of vitamin B12
How is pepsinogen converted to pepsin and what does it cut?
H+ ion.
Cuts peptide bonds near aromatic amino acids.
What cell type do the pyloric glands contain? And what do they secrete? What is the function of the thing that they secrete?
G cells
Secrete Gastrin
1-Induces the secretion of HCL from the parietal cells
2- signals the stomach to contract
Name two compounds that are directly absorbed in the stomach
Alcohol and aspirin