Biology - Digestive System - MCAT Practice Questions
Mechanical digestion is the physical breakdown of large food molecules into
smaller particles. What is the process that specifically refers to the
enzymatic cleavage of chemical bonds, such as the peptide bonds of
proteins? Chemical digestion
The contraction and relaxation of muscles that propels food down the gut
tube is known as: Peristalsis
The complete digestive pathway includes the oral cavity, pharynx, esophagus,
stomach, small intestine, large intestine, and rectum. Which organ
immediately follows the pharynx? Esophagus
Which two enzymes are secreted in the oral cavity to start the chemical
digestion of food? Salivary amylase and lipase
The pharynx connects the mouth to the esophagus. What structure prevents
food from entering the larynx during the swallowing process? Epiglottis
The esophagus is unique in its muscular control. The top third of the
esophagus is under which type of control? Somatic control
Which of the following is NOT one of the four main anatomical parts of the
stomach? Cecum
Mucous cells in the stomach produce mucus rich in which substance to protect
the stomach wall from its acidic environment? Bicarbonate
Chief cells in the stomach lining are responsible for secreting: Pepsinogen and gastric lipase
Parietal cells in the stomach secrete HCl and which other substance, which
is essential for vitamin B₁₂ absorption? Intrinsic factor
What is the peptide hormone secreted by G-cells that increases HCl secretion
and gastric motility? Gastrin
After mechanical and chemical processing in the stomach, the resulting
semifluid mass of partially digested food is called: Chyme
The highly acidic environment of the stomach is maintained by a pH of
approximately: 2
Which segment of the small intestine is the first part that chyme enters and
is the site of the majority of chemical digestion? Duodenum
The brush-border enzyme enteropeptidase (enterokinase) has the specific
function of: Activating trypsinogen to make trypsin.
Trypsin is an enzyme that catalyzes the hydrolysis of which specific bonds,
aiding in the breakdown of proteins into smaller peptides? Peptide bonds
Which pair of hormones, released by the duodenum, stimulates the release of
pancreatic juices and bile, thereby aiding in digestion? Secretin and Cholecystokinin (CCK)
Which duodenal hormone stimulates the release of pancreatic juices,
including bicarbonate to neutralize chyme, and also acts to slow
motility? Secretin
Cholecystokinin (CCK) is a hormone that stimulates the release of pancreatic
juices and promotes satiety. It is also the main stimulator for the release
of bile from which organ? Gallbladder
The primary function of the jejunum and ileum of the small intestine is: Absorption of nutrients
The small intestine's inner lining is covered with small finger-like
projections of tissue called villi, which are themselves covered with even
smaller projections called: Microvilli
The fat-soluble vitamins, which are absorbed through the lacteals within the
small intestine's villi, are: A, D, E, and K
Which accessory organ synthesizes bile, albumin, and clotting factors? Liver
Bile is made in the liver and is stored and concentrated in the: Gallbladder
The hormones ADH (antidiuretic hormone) and aldosterone both have the effect
of: Increasing water absorption in the large intestine