The Complexity and Number of Atria and Ventricles in the Heart

question 235

Short Answer

The complexity and number of atria and ventricles in the heart increase from fishes to amphibians to nonavian reptiles to mammals and birds.An important consequence of this increased complexity is the gradual separation of the circulatory system into two independent circuits: the pulmonary involving the lungs and the _______ involving the body.

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Definitions:

Cholecystokinin (CCK)

A hormone that stimulates the digestion of fat and protein.

Cholecystokinin

A hormone that stimulates the digestion of fat and protein by prompting the release of digestive enzymes and bile from the pancreas and gallbladder, respectively.

Secretin

A hormone that stimulates the secretion of digestive juices from the pancreas and bile from the liver into the small intestine.

Ileocecal Sphincter

Thickening of circular smooth muscle between the ileum and the cecum, forming the ileocecal valve.