Chapter 23: The Digestive system GI tract

Mucosa

• Consists of epithelium and lamina propria

• Has a thin, smooth layer called the muscularis muscosae

• Referred to as mucous membrane because mucus production is a characteristic feature of gut epithelium

Submucosa

• Lies immediately beneath the mucosa

• It is a broad layer of connective tissue that connects the overlying mucosa to underlying muscularis

• Include blood & lymphatic vessels and a scattering of submission glands that release digestive secretions

• Serves as conduit for dense branching network of nerves (submucosal plexus)

Muscularis

• in small intestine and made up of a double layer of smooth muscle (inner circular layer & outer longitudinal layer)

• contractions from the layers promote mechanical digestion, expose more of food to digestive chemicals, and move food along the canal

• in distal & proximal regions it is made up of skeletal muscle which give you voluntary control over swallowing & defecation

Serosa

• superficial to muscularis

• consists of a layer of visceral peritoneum overlying a layer of looser connective tissue