GI Worksheet – worth 25 points
Keep your answers simple and straightforward – Upload to Canvas Score: ___________/25pts
Due date: Nov 29, 2020
A. Stomach: video below (5:57mins)
https://www.khanacademy.org/science/health-and-medicine/human-anatomy-and-physiology/
gastrointestinal-system-introduction/v/stomach
1. Job of the stomach is to receive the bolus, then it does:
a. Mixing and breakdown of food by contraction and relaxation of the muscle layers in the
stomach & digestion of food
b. Food is broken down into a thick, acidic, soupy mixture known as chyme
At this point, chyme is formed and held for 2 hours or longer
until it is an appropriate time to be squirted into the duodenum.
2. Gastric anatomy:
Type of cell within gastric The secretion that is made and released from this
pits/gastric glands cell
Secrete mucus to form a protective layer around the
stomach lining.
Goblet cells
Secretes hydrochloric acid, which is responsible for
Parietal Cells creating a low pH environment in the stomach.
It secretes gastrin (stimulates the release of stomach
G cells acids to increase stomach acidity)
3. How is pepsin made?
Gastric chief cells secrete pepsin as an inactive zymogen called pepsinogen. Parietal cells within
the stomach lining secrete hydrochloric acid that lowers the pH of the stomach. A low pH (1.5 to
2) activates pepsin.
4. What is pepsin used to hydrolyze in the stomach?
Pepsin is a stomach enzyme that serves to digest proteins found in ingested food. It breaks down
proteins into smaller peptides.
5. What protects the stomach from the HCl that it releases?
Mucus lining loaded with bicarbonate molecules helps protect against hydrochloric acid and
creates a near-neutral pH environment that deactivates pepsin.
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, B. Small Intestine 1 – Structure: video below (6:30mins)
https://www.khanacademy.org/test-prep/nclex-rn/rn-gastrointestinal-system/rn-the-gastrointestinal-
system/v/small-intestine-part-1
6. Major parts of small intestine
Major part of small intestine Major job/function of this part
From the stomach, the food enters the duodenum,
Duodenum which produces hormones and receives secretions
such as bile and pancreatic juice from the liver and
pancreas(pancreatic juice)
its primary function is to absorb sugar, amino acids,
Jejunum and fatty acids
Absorbs any remaining nutrients, for example, vitamin
Ileum B 12
7. Delivery into the small intestine?
What is being delivered to the SI? From where did it come?
Bile Liver
Enzymes Liver
Digestive juices Liver
8. What is the intestinal villi's primary function and the microvilli on the apical surface of the
simple columnar epithelial cells?
The villi and microvilli increase intestinal absorptive surface area approximately 30 fold and 600
fold, respectively. Overall, they help in the absorption process.
C. Small Intestine 2 – Digestion: see video below (6:44mins)
https://www.khanacademy.org/test-prep/nclex-rn/rn-gastrointestinal-system/rn-the-gastrointestinal-
system/v/small-intestine-part-2-digestion
9. Chemical Digestion of Macromolecules
Macromolecule Composed of what building block Chemically digested by
Fatty Acids/Glycerol Lipase
Lipids
Proteins Amino Acids Chymotrypsin/ Trypsin
Nucleic Acids Nucleotides Ribonuclease/Deoxyribonuclease
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