Explain about the Oral cavity and alimental-y tract?

Various functional changes and decline in secretary function occur in the digestive tract with aging. These include:

Oral cavity - The dentition are affected, (loosening of teeth, tooth decay and gum deterioration with age), saliva secretion decreases leading to dry mouth (xerostomia).

Gastric - Reduced gastric secretion and gastric emptying is common in elderly.  Some authors consider it to be due to aging whereas other investigators consider it to be due to helicobacter pylori. This affects the iron availability from the diet.  Vitamin B,, deficiency also observed due to decreased gastric intrinsic factor. Due to the reduction in intestinal colon motility and poor muscle tone of abdomen along with decrease in dietary fiber intake and low physical activity associated with aging, constipation is a common problem observed.