What are the two groups of organs making up the digestive system? correct answers 1. GI tract
(mouth, pharynx, esophagus, stomach, small intestine, large intestine, anus)
2. Accessory digestive organs (teeth, tongue, salivary glands, liver, gallbladder, pancreas)
What are the 5 essential activities of the digestive process? correct answers 1. Digestion
(mechanical and chemical breakdown)
2. Absorption
3. Secretion
4. Motility (skeletal and smooth muscle)
5. Elimination
What are the 4 layers of the GI tract (and their sublayers) from most internal to external? correct
answers 1. Mucosa
- Epithelium
- Lamina Propria
- Muscularis mucosa
2. Submucosa
3. Muscularis externa
- Longitudinal muscle
- Circular muscle
4. Serosa
- Epithelium
- Connective tissue
What are the 3 functions of the mucosa layer? correct answers 1. Secretes mucus, pH secretions,
digestive enzymes, hormones
2. Absorbs end products of digestion
3. Protects against infectious disease
What is the function of the muscularis externa layer? correct answers Peristalsis and
segmentation
What is the difference between peristalsis and segmentation? correct answers Peristalsis is when
adjacent segments contract and relax to propel food distally. Segmentation is was nonadjacent
segment contract and relax, moving food forward and backward to mix it.
The mouth, pharynx, and esophagus are composed of what type of cells? correct answers
Stratified squamous
What cell type is in the stomach, small intestine, and large intestine? correct answers Simple
columnar
What 5 types of secretions are in the stomach? correct answers 1. Bicarbonate (alkaline mucus)
2. Gastric pits produce gastric juice
, 3. Parietal cells secrete HCl and intrinsic factor
4. Chief cells secrete pepsinogen and gastric lipase
5. G cells secrete gastrin (hormone)
What 3 structures increase surface area in the small intestine? correct answers 1. Circular folds
2. Villi
3. Microvilli
Crypts, or the divots in between villi, contain both correct answers Secretory and
enteroendocrine cells (producing digestive hormones)
The mouth helps with both mechanical and chemical breakdown, but undergoes almost no
absorption. What are the 2 enzymes aiding chemical breakdown here? correct answers 1.
Salivary amylase (secreted by 3 external glands, breaks down starch into simple sugars at neutral
pH)
2. Lingual lipase (secreted by surface of the tongue, breaks down fats at acidic pH)
Which salivary glands secretes mostly serous? What about mucus? correct answers Parotid and
Submandibular are mostly serous, while Sublingual is mostly mucus
What is the most concentrated source of stored energy? How do you break/form this molecule?
correct answers Triglyceride. To break, it undergoes hydrolysis. To form, it undergoes
dehydration synthesis.
___ hydrolyze nucleic acids into nucleotides. correct answers Nucleases
___ + ___ = pepsin correct answers Pepsinogen + HCl
What two enzymes do parietal cells in the fundus and body secrete? correct answers 1. HCl
(denatures proteins, activates pepsin, breaks down plant cell walls)
2. Intrinsic factor (protein required for vitamin B12 absorption in small intestine)
What are the 4 steps regarding HCl secretion by parietal cells? correct answers 1. CO2 is
dissolved in water, providing a free H+ ion
2. This H+ ion is pumped into the stomach using the H+/K+ pump
3. Cl- is transported through the parietal cell and into the stomach by HCO3- (an antiporter)
4. The free H+ and Cl- combine in the stomach to form HCl
Blood surrounding the stomach is more correct answers Alkaline due to the extra HCO3 being
transported out of the parietal cells
Pepsinogen is the ___ form of pepsin, which is most active at pH ___ and digests ___ correct
answers Pepsin, 2, proteins
___ is denatured in the stomach. ___ digests triglycerides to diglycerides and fatty acids. correct
answers Salivary amylase, gastric lipase