Bird, ventriculus (LM, Low)

Structure List Lumen of ventriculus Keratinoid material Mucosa Smooth muscle of externa Skeletal muscle of externa

AVIAN VENTRICULUS (OR GIZZARD). The primary function of the gizzard is to grind up food and mix digestive enzymes and acids with it. The lumen of the gizzard is lined by a keratinoid material which is secreted by the tubular glands of the mucosa. The epithelium is simple columnar and forms pits in the lamina propria which end in glands. The muscularis externa contains a thick inner layer of smooth muscle and a thicker outer layer of skeletal muscle.