Changes

*Membrane bound enzymes and transport proteins are also within the epithelium.

*Membrane bound enzymes and transport proteins are also within the epithelium.

*Each villus houses capillaries that transport amino acids, monosaccharides and other digestive products and lacteals that transport triacylglycerides. Lacteals drain into the lymphatic system.

*Each villus houses capillaries that transport amino acids, monosaccharides and other digestive products and lacteals that transport triacylglycerides. Lacteals drain into the lymphatic system.

*Crypts are present at the base of each villus in the mucosa. Cell types in mucosal crypts (from luminal to basal):

*'''Crypts''' are present at the base of each villus in the mucosa. Cell types in mucosal crypts (from luminal to basal):

**''goblet''  at the tip of the crypt. Produce mucous by exocytosis.

**''goblet''  at the tip of the crypt. Produce mucous by exocytosis.

**''entero-endocrine''  in the middle of the crypt. Secrete peptides and amines.

**''entero-endocrine''  in the middle of the crypt. Secrete peptides and amines.

**''paneth''  at the base of the crypt. Function unknown. Contain eosinophilic granules.

**''paneth''  at the base of the crypt. Function unknown. Contain eosinophilic granules.

*Brunner's glands ane present in the submucosa.

*'''Brunner's glands''' are present in the submucosa.

**They produce an alkaline secretion which neutralises stomach acid.

**They produce an alkaline secretion which neutralises stomach acid.

**They open into the crypts above in the mucosa.

**They open into the crypts above in the mucosa.