introduction and cholecystokinin

1. •OVERVIEW
•GENERAL FEATURES
•CHOLECYSTOKININ
•FEATURES AND
FUNCTIONS
•MECHANISM OF
ACTION
•REGULATION

4.  Modulate activity of digestive system
 They are peptides
 Not released by endocrine glands but
secreted throughout large areas of the
GI Mucosa.
 These cells called enteroendocrine cells.
 They enter the circulatory system and
not the lumen of the GI tract

5. LOCATION OF ENTEROENDROCRINE CELLS

7.  It is a linear peptide synthesized by I cells
( a type of entero-entocrine cell) of
duodenum and Jejunum
 Made up of 8 to 59 amino acids
 Also synthesized in small amounts by the
Brain
 Have two receptors, CCK A(present
mainly in the pancreatic acinar cells)
and CCK B

8. Diagram showing location of I cells and secretion of CCK into the bloodstream

11.  The most potent stimuli for
secretion of cholecystokinin are
the presence of partially-digested
fats and proteins in the lumen of
the duodenum

13. MECHANISM OF ACTION

17. It’s all under control