MLT GlobeAnatomy: Digestive system – page 2
38 Anatomy MCQs on Digestive system with answers and explanations.
The myenteric (Auerbach) plexus, which controls gut peristalsis, lies within which layer?
The myenteric plexus lies between circular and longitudinal muscle layers. The submucosal (Meissner) plexus is in the submucosa and controls secretion.
At what vertebral level does the oesophagus pass through the diaphragm?
The oesophageal hiatus is at T10. The inferior vena cava passes at T8 and the aorta at T12.
The adult anal canal is approximately how long?
The anal canal is about 3.8–4 cm long, running from the anorectal junction to the anus; the rectum above is about 12 cm.
The caecum, ascending colon and most of the transverse colon are supplied by which artery?
The superior mesenteric artery supplies midgut derivatives up to the distal third of the transverse colon; the inferior mesenteric supplies the hindgut.
The caecum receives blood through the ileocolic branch of which artery?
The ileocolic artery, a branch of the superior mesenteric, supplies the caecum and appendix. Rectal arteries supply the rectum and anal canal.
Voluntary control of the external anal sphincter is provided by which nerve?
The pudendal nerve (S2–S4), via its inferior rectal branch, supplies the external anal sphincter and perineal skin.
Which statement about the stomach is correct?
The lesser omentum links the lesser curvature to the liver; the greater omentum hangs from the greater curvature. The stomach lies mainly in the left upper quadrant.
Most ingested and secreted water is reabsorbed in the:
About 80–90% of water entering the gut is absorbed in the small intestine; the colon absorbs most of the remainder.
About three-quarters of the blood entering the liver arrives through which vessel?
The portal vein delivers about 75% of hepatic inflow (nutrient-rich); the hepatic artery supplies about 25%, carrying most of the oxygen. Hepatic veins drain the liver.
The artery supplying the gallbladder usually arises from the right hepatic artery. What is it called?
The cystic artery normally branches from the right hepatic artery. The left gastric and splenic arteries arise from the coeliac trunk.
The abdominal aorta forms part of the stomach bed. To which surface of the stomach is it related?
The stomach bed, behind the posterior surface, includes the pancreas, left kidney, spleen and aorta.
Which structures pass through the porta hepatis?
The porta hepatis transmits the portal vein, hepatic artery proper branches and hepatic ducts, plus nerves and lymphatics. Hepatic veins leave posteriorly.
Which type of lingual papilla, the most numerous on the tongue, carries NO taste buds?
Filiform papillae are mechanical and lack taste buds. Circumvallate, fungiform and foliate papillae carry taste buds, which also occur on the soft palate, pharynx and epiglottis.
Which tissue covering the tooth root gives attachment to periodontal ligament fibres, anchoring the tooth in its socket?
Cementum coats the root and holds the periodontal ligament fibres that tie the tooth to the alveolar bone. Enamel covers the crown; dentine and pulp form the tooth's interior.
Saliva entering the mouth through a duct opposite the upper second molar comes from which gland?
The parotid (Stensen's) duct opens on the buccal mucosa opposite the upper second molar. Submandibular ducts open beside the lingual frenulum, and sublingual glands open along the floor of the mouth.
Which segment of the intestine is the longest?
The ileum forms about the distal three-fifths of the small intestine (roughly 3 m or more). The jejunum is shorter, the duodenum only about 25 cm, and the large intestine about 1.5 m.
The cystic vein drains blood from which organ?
Cystic veins from the gallbladder drain into the portal vein or directly into the liver. 'Cystic' here refers to the gallbladder, not the urinary bladder.
Which muscular valve controls the flow of bile and pancreatic juice into the duodenum?
The sphincter of Oddi surrounds the ampulla of Vater and regulates bile flow; Wirsung is the main pancreatic duct.