Review for unit 1
Review for chapter 23:
Identify the parts of digestive system: digestive organs and the accessory
organs of alimentary canal and label them.
Digestive organs of the alimentary
canal: mouth, pharynx, esophagus, stomach, small intestine, and large intestine.
Accessory digestive organs: teeth, tongue, gallbladder, and a number of large
digestive glands—salivary glands, liver, and pancreas. See Fig 23.1 page 883.
What are the different digestive processes? familiarize with Fig 23.2.
—taking food into the digestive tract, usually via the mouth
—moves food through the alimentary canal, includes
swallowing (which is voluntary), and peristalsis (involuntary)
—physically prepares food for chemical digestion
by enzymes; includes chewing, mixing of food with saliva and by the
tongue, churning food in the stomach, and segmentation
—a series of catabolic steps in which complex food
molecules are broken down to their chemical building blocks by enzymes
secreted into the lumen of the alimentary canal
—the passage of digested end products (plus vitamins,
minerals, and water) from the lumen of the GI tract through the mucosal
cells by active or passive transport into the blood or lymph (small intestine
is the major absorptive site)
—eliminates indigestible substances form the body via the anus
in the form of feces
What are peristalsis and segmentation? Peristalsis
waves of contraction and relaxation of muscles in the organ walls (it is the
major means of propulsion), its main effect is to squeeze food along the
tract, but some mixing occurs as well; it moves in ONE direction.
—rhythmic local constrictions of the intestine; it mixes food
with digestive juices and increases the efficiency of absorption by
repeatedly moving different parts of the food mass over the intestinal
walls; it allows the food to mix by going back and forth.
What are long and short nerve controls?
—mediated entirely by
the local plexuses in response to the GI tract stimuli; long
stimuli arising inside or outside the GI tract and involve CNS centers and
extrinsic autonomic nerves. See Fig 23.4 page 885.
What is visceral peritoneum,? mesentery? retroperitoneal and
Digestive organs are covered by two layered
peritoneum. The layer close to the organs are called
, the one
adjacent to the body wall is called parietal peritoneum. Some organs (like the
stomach) have two layers of serous membranes fused to each other and extend the
organ to the body wall, called
. It is mostly dorsal, but can be ventral.
These organs are called peritoneal or