Glands associated with alimentary canal are: 

(1) Salivary glands: A salivary gland may be defined as any cell or organ which discharges a secretion into the oral cavity. Human salivary glands are classified into two categories: major salivary glands and minor salivary glands. 

(a) Major Salivary glands: In man the major salivary glands are three pairs: parotid, sublingual and submandibular glands. 

(i) Parotid glands: These are the largest salivary glands which are situated near the ears. Their ducts open into the oral cavity near the upper second molars. The duct of parotid gland is called Stenson’s duct.

(ii) Sublingual glands: These are small-sized salivary glands which are located beneath the tongue and their ducts are called sublingual ducts or ducts of Rivinus. 

(iii) Submandibular glands: These are medium sized salivary glands which are located at the angles of the lower jaw. Their ducts open into the oral cavity near the lower central incisors. The duct of submandibular gland is called Wharton's duct. The parotid salivary glands secrete much of salivary amylase. 

(b) Minor salivary glands: There are numerous small glands situated in the mucous membrane of the lips (libial glands), Cheeks (buccal glands), tongue lingual glands) and palate (palatine glands). The secretions of these glands help to keep the mouth moist and provide a protective and lubricant coat of mucus. The fluids secreted by major and minor salivary glands constitute saliva. 

(2) Gastric glands: These are numerous microscopic, tubular glands formed by the epithelium of the stomach. The following types of cells are present in the epithelium of the gastric glands. 

(i) Peptic cells: (= chief or Zymogenic or Zymogen cells). They are usually basal in location and secrete gastric digestive enzymes as proenzymes or zymogens; pepsinogen and prorennin. 

(ii) Oxyntic cells: They are large and are most numerous on the side walls of the gastric glands They secrete hydrochloric acid and Castle’s intrinsic factor. 

(iii) Mucous cells: They are present between other types of cells and secrete mucus. 

(3) Liver: It is the largest gland of the body which secrete heparin (anticoagulant). It also produces bile. 

(4) Pancreas: It is a soft lobulated pinkish gland which secretes two major hormones:

 (i) Insulin, 

(ii) Glucagon.

(5) Intestinal gland: These are formed by the surface epithelium of small intestine. 

These are of two types: 

(i) Crypts of Lieberkuhn which secrete mucus and digestive enzymes. 

(ii) Brunner's gland found in duodenum which secretes mucus.