NST 103 Midterm 1 UPDATED A Exam
Questions and CORRECT Answers
incomplete digestive tract - CORRECT ANSWER - digestive tract with one opening that
takes in food and ejects wastes. The gastrovascular cavity can tentacles and water flowing
through it.
complete digestive tract - CORRECT ANSWER - a digestive tube with two openings, a
mouth and an anus, that allows for atomnomical absorption
GI Tract - CORRECT ANSWER - Oral Cavity --> Esophagus --> stomach --> small intestine
--> large intestine
GI tract accessory glands - CORRECT ANSWER - Salivary Glands in the oral cavity and the
liver, gallbladder, pancreas, in the small intestine
What are the functions of the GI Tract? - CORRECT ANSWER - Digestion, Absorption,
Secretion, motility, storage, elimination and barrier
Digestion - CORRECT ANSWER - reduce size of molecule and repackage
Absorption - CORRECT ANSWER - movement from GI tract to blood or lymph
Secretion - CORRECT ANSWER - movement into the lumen
Motility - CORRECT ANSWER - muscles mix and move contents via peristalsis
Barrier - CORRECT ANSWER - between the external and internal environments
,What are the goals and functions of the oral cavity? - CORRECT ANSWER - Goal = food
bolus
Functions - chewing, initiate digestion, swallowing
Salivary Glands features - CORRECT ANSWER - Tongue, sublingual gland, submandibular
gland, lymph nodes, parotid gland
Saliva functions - CORRECT ANSWER - - Water in saliva moistens food
- Glycoproteins in saliva lubricate and prevent abrasion
- Salivary amylase initiates digestion of starch
- antimicrobial agents reduce risk of infection
Layers of GI Tract - CORRECT ANSWER - 1. Mucosa
2. Submucosa
3. Muscularis
4. Serosa
Peristalsis - CORRECT ANSWER - the process of swallowing. Esophageal sphincter makes
wave-like muscle contractions of the alimentary tract that moves food along.
Stomach Anatomy - CORRECT ANSWER - 1. fundus
2. lower esophageal sphincter
3. cardia
4. body
5. muscularis: longitudinal layer, circular layer, oblique layer
6. Rugae of mucosa
7. Pyloric Antrium
8. Pyloric Sphincter
,Stomach goal - CORRECT ANSWER - form chyme (food + secretions)
Stomach functions - CORRECT ANSWER - - Store food
- secrete acid, pepsinogen, mucus
- initiates digestion of proteins and lipids
- kill bacteria
- some absorption of ethanol, some drugs and other small water-soluble compounds
The stomach secretes gastric juice. What makes up gastric juice? - CORRECT ANSWER --
HCl and intrinsic factor
- Pepsinogen and gastric lipase
- mucus
- water, electrolytes, bicarbonate
Chief cells secrete pepsin. How? - CORRECT ANSWER - In the lumen of the stomach,
pepsinogen interacts with HCl to create pepsin.
- Pepsinogen (42kDa) is the inactive precursor
- Pepsin (35kDa) is a protease with a pH optimum of 2.0 and induces activation
What is pepsin? - CORRECT ANSWER - Pepsin is an enzyme that breaks down ingested
protein into short peptides
HCl is needed to secrete pepsin. Where does it come from? - CORRECT ANSWER -
Reaction occurs in the partial cell that releases Cl- and H+ into the stomach lumen where they
then bind together. binds Cl- with H+ in the stomach lumen.
This process acidifies the stomach lumen.
Synthesis of Histamine - CORRECT ANSWER - Histidine -(histidine decarboxylase)>
Histamine
CO2 molecule is lost in this reaction
, What is Histamine? - CORRECT ANSWER - - an essential amino acid
- important for immune response and allergic symptoms
- Pyridoxal phosphate is an essential vitamin, and acts as a coenzyme to facilitate the
decarboxylation reaction
Gastrin - CORRECT ANSWER - regulates histidine decarboxylase synthesis in the ECL cell
Somatostatin - CORRECT ANSWER - Inhibits production of HCl
- produced by D-cells of stomach, duodenum & pancreas
Parietal cells - CORRECT ANSWER - Secrete H+ and Cl- by:
1. carbonic anhydrase catalyzes the formation of H+ and HCO3- from water and CO2
2. HCO3- is transported out of the cell in exchange for Cl-
3. Cl- is transported down its concentration gradient into the stomach lumen
4. H+ is actively pumped (ATP-dependent) into the stomach lumen by the H+/K+ ATPase
Positive regulation of stomach acidification - CORRECT ANSWER - Vagal nerve
(acetylcholine), ECL cells (Histamine), and G Cells (Gastrin)
Negative regulation of stomach acidification - CORRECT ANSWER - D-cells (somatostatin)
What is heart burn? - CORRECT ANSWER - Acid Reflux. Stomach acid goes back up into
the esophagus
Acid Reflux treatments - CORRECT ANSWER - Three treatments because there are three
ways to reduce HCl:
1. Antacids - affects the HCl in the stomach lumen (ex. Alka-Seltzer, Pepto-Bismol )
2. Protein pump inhibitor - inhibits the protein pump in parietal cell (Prilosec)
Questions and CORRECT Answers
incomplete digestive tract - CORRECT ANSWER - digestive tract with one opening that
takes in food and ejects wastes. The gastrovascular cavity can tentacles and water flowing
through it.
complete digestive tract - CORRECT ANSWER - a digestive tube with two openings, a
mouth and an anus, that allows for atomnomical absorption
GI Tract - CORRECT ANSWER - Oral Cavity --> Esophagus --> stomach --> small intestine
--> large intestine
GI tract accessory glands - CORRECT ANSWER - Salivary Glands in the oral cavity and the
liver, gallbladder, pancreas, in the small intestine
What are the functions of the GI Tract? - CORRECT ANSWER - Digestion, Absorption,
Secretion, motility, storage, elimination and barrier
Digestion - CORRECT ANSWER - reduce size of molecule and repackage
Absorption - CORRECT ANSWER - movement from GI tract to blood or lymph
Secretion - CORRECT ANSWER - movement into the lumen
Motility - CORRECT ANSWER - muscles mix and move contents via peristalsis
Barrier - CORRECT ANSWER - between the external and internal environments
,What are the goals and functions of the oral cavity? - CORRECT ANSWER - Goal = food
bolus
Functions - chewing, initiate digestion, swallowing
Salivary Glands features - CORRECT ANSWER - Tongue, sublingual gland, submandibular
gland, lymph nodes, parotid gland
Saliva functions - CORRECT ANSWER - - Water in saliva moistens food
- Glycoproteins in saliva lubricate and prevent abrasion
- Salivary amylase initiates digestion of starch
- antimicrobial agents reduce risk of infection
Layers of GI Tract - CORRECT ANSWER - 1. Mucosa
2. Submucosa
3. Muscularis
4. Serosa
Peristalsis - CORRECT ANSWER - the process of swallowing. Esophageal sphincter makes
wave-like muscle contractions of the alimentary tract that moves food along.
Stomach Anatomy - CORRECT ANSWER - 1. fundus
2. lower esophageal sphincter
3. cardia
4. body
5. muscularis: longitudinal layer, circular layer, oblique layer
6. Rugae of mucosa
7. Pyloric Antrium
8. Pyloric Sphincter
,Stomach goal - CORRECT ANSWER - form chyme (food + secretions)
Stomach functions - CORRECT ANSWER - - Store food
- secrete acid, pepsinogen, mucus
- initiates digestion of proteins and lipids
- kill bacteria
- some absorption of ethanol, some drugs and other small water-soluble compounds
The stomach secretes gastric juice. What makes up gastric juice? - CORRECT ANSWER --
HCl and intrinsic factor
- Pepsinogen and gastric lipase
- mucus
- water, electrolytes, bicarbonate
Chief cells secrete pepsin. How? - CORRECT ANSWER - In the lumen of the stomach,
pepsinogen interacts with HCl to create pepsin.
- Pepsinogen (42kDa) is the inactive precursor
- Pepsin (35kDa) is a protease with a pH optimum of 2.0 and induces activation
What is pepsin? - CORRECT ANSWER - Pepsin is an enzyme that breaks down ingested
protein into short peptides
HCl is needed to secrete pepsin. Where does it come from? - CORRECT ANSWER -
Reaction occurs in the partial cell that releases Cl- and H+ into the stomach lumen where they
then bind together. binds Cl- with H+ in the stomach lumen.
This process acidifies the stomach lumen.
Synthesis of Histamine - CORRECT ANSWER - Histidine -(histidine decarboxylase)>
Histamine
CO2 molecule is lost in this reaction
, What is Histamine? - CORRECT ANSWER - - an essential amino acid
- important for immune response and allergic symptoms
- Pyridoxal phosphate is an essential vitamin, and acts as a coenzyme to facilitate the
decarboxylation reaction
Gastrin - CORRECT ANSWER - regulates histidine decarboxylase synthesis in the ECL cell
Somatostatin - CORRECT ANSWER - Inhibits production of HCl
- produced by D-cells of stomach, duodenum & pancreas
Parietal cells - CORRECT ANSWER - Secrete H+ and Cl- by:
1. carbonic anhydrase catalyzes the formation of H+ and HCO3- from water and CO2
2. HCO3- is transported out of the cell in exchange for Cl-
3. Cl- is transported down its concentration gradient into the stomach lumen
4. H+ is actively pumped (ATP-dependent) into the stomach lumen by the H+/K+ ATPase
Positive regulation of stomach acidification - CORRECT ANSWER - Vagal nerve
(acetylcholine), ECL cells (Histamine), and G Cells (Gastrin)
Negative regulation of stomach acidification - CORRECT ANSWER - D-cells (somatostatin)
What is heart burn? - CORRECT ANSWER - Acid Reflux. Stomach acid goes back up into
the esophagus
Acid Reflux treatments - CORRECT ANSWER - Three treatments because there are three
ways to reduce HCl:
1. Antacids - affects the HCl in the stomach lumen (ex. Alka-Seltzer, Pepto-Bismol )
2. Protein pump inhibitor - inhibits the protein pump in parietal cell (Prilosec)
