Digestion Secretion and Absorption Flashcards
What is digestion
Complex molecules undergo enzymatic degradation to absorbable forms
What is absorption
Process by which molecules transported through epithelium to enter blood
Where does the secretion of saliva occur?
Parotid
Sublingual
Submandibular
Buccal
Where does primary secretion occcur?
acinar cells
What is aqueous secretion
similar compostition to ECF
where does serous secretion occur and what does it contain
Parotid
contains ptyalin and lysozyme
Where does modification of the saliva of the occur
Ductal epithelium
What does modification of saliva consist of
Na+ Cl- absorption
K+ HC03- secretion
What is salivary secretion stimulated by and what does this cause?
Chemoreceptors/mechanoreceptors
higher centres CNS
Causes an increase in parasympathetic activity
Where does gastric secretion occur?
Columnar epithelial cells Oxyntic glands -mucous neck cells - parietal cells -Enterochromaffin- like cells - chief cells pyloric cells
what do the columnar epithelial cells secrete
Mucous , HC03 - for protection
What do the oxyntic cells secrete
HCl
pepsinogen
intrinsic fx
What do the pyloric glands secrete
Gastrin and mucous
What mediates slow waves in GI smooth msucle
intersitial cells of cajal
What do segmentation contractions involve
Stretch
localised concentric segmentation and mixing of chyme
