Explanation:
Table 1. Contribution of Other Body Systems to the Digestive System
Body systemBenefits received by the digestive system
CardiovascularBlood supplies digestive organs with oxygen and processed nutrients
EndocrineEndocrine hormones help regulate secretion in digestive glands and accessory organs
IntegumentarySkin helps protect digestive organs and synthesizes vitamin D for calcium absorption
LymphaticMucosa-associated lymphoid tissue and other lymphatic tissue defend against entry of pathogens; lacteals absorb lipids; and lymphatic vessels transport lipids to bloodstream
MuscularSkeletal muscles support and protect abdominal organs
NervousSensory and motor neurons help regulate secretions and muscle contractions in the digestive tract
RespiratoryRespiratory organs provide oxygen and remove carbon dioxide
SkeletalBones help protect and support digestive organs
UrinaryKidneys convert vitamin D into its active form, allowing calcium absorption in the small intestine
Digestive System Organs
The easiest way to understand the digestive system is to divide its organs into two main categories. The first group is the organs that make up the alimentary canal. Accessory digestive organs comprise the second group and are critical for orchestrating the breakdown of food and the assimilation of its nutrients into the body. Accessory digestive organs, despite their name, are critical to the function of the digestive system.
Table 2. The Five Major Peritoneal Folds
FoldDescription
Greater omentumApron-like structure that lies superficial to the small intestine and transverse colon; a site of fat deposition in people who are overweight
Falciform ligamentAnchors the liver to the anterior abdominal wall and inferior border of the diaphragm
Lesser omentumSuspends the stomach from the inferior border of the liver; provides a pathway for structures connecting to the liver
MesenteryVertical band of tissue anterior to the lumbar vertebrae and anchoring all of the small intestine except the initial portion (the duodenum)
MesocolonAttaches two portions of the large intestine (the transverse and sigmoid colon) to the posterior abdominal wall
accessory digestive organ: includes teeth, tongue, salivary glands, gallbladder, liver, and pancreas
alimentary canal: continuous muscular digestive tube that extends from the mouth to the anus
motility: movement of food through the GI tract
mucosa: innermost lining of the alimentary canal
muscularis: muscle (skeletal or smooth) layer of the alimentary canal wall
myenteric plexus: (plexus of Auerbach) major nerve supply to alimentary canal wall; controls motility
retroperitoneal: located posterior to the peritoneum
serosa: outermost layer of the alimentary canal wall present in regions within the abdominal cavity
submucosa: layer of dense connective tissue in the alimentary canal wall that binds the overlying mucosa to the underlying muscularis
submucosal plexus: (plexus of Meissner) nerve supply that regulates activity of glands and smooth muscle
