NST 103 Midterm 1 Exam 2025
Questions and Answers
incomplete digestive tract - 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 - ANSWER✔✔-a digestive tube with two openings, a mouth
and an anus, that allows for atomnomical absorption
GI Tract - ANSWER✔✔-Oral Cavity --> Esophagus --> stomach --> small intestine -->
large intestine
GI tract accessory glands - ANSWER✔✔-Salivary Glands in the oral cavity and the
liver, gallbladder, pancreas, in the small intestine
What are the functions of the GI Tract? - ANSWER✔✔-Digestion, Absorption, Secretion,
motility, storage, elimination and barrier
Digestion - ANSWER✔✔-reduce size of molecule and repackage
,Absorption - ANSWER✔✔-movement from GI tract to blood or lymph
Secretion - ANSWER✔✔-movement into the lumen
Motility - ANSWER✔✔-muscles mix and move contents via peristalsis
Barrier - ANSWER✔✔-between the external and internal environments
What are the goals and functions of the oral cavity? - ANSWER✔✔-Goal = food bolus
Functions - chewing, initiate digestion, swallowing
Salivary Glands features - ANSWER✔✔-Tongue, sublingual gland, submandibular
gland, lymph nodes, parotid gland
Saliva functions - 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 - ANSWER✔✔-1. Mucosa
2. Submucosa
3. Muscularis
4. Serosa
,Peristalsis - ANSWER✔✔-the process of swallowing. Esophageal sphincter makes
wave-like muscle contractions of the alimentary tract that moves food along.
Stomach Anatomy - 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 - ANSWER✔✔-form chyme (food + secretions)
Stomach functions - 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? - ANSWER✔✔-- HCl
and intrinsic factor
- Pepsinogen and gastric lipase
- mucus
- water, electrolytes, bicarbonate
Chief cells secrete pepsin. How? - 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? - ANSWER✔✔-Pepsin is an enzyme that breaks down ingested protein
into short peptides
HCl is needed to secrete pepsin. Where does it come from? - 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 - ANSWER✔✔-Histidine -(histidine decarboxylase)> Histamine
CO2 molecule is lost in this reaction
Questions and Answers
incomplete digestive tract - 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 - ANSWER✔✔-a digestive tube with two openings, a mouth
and an anus, that allows for atomnomical absorption
GI Tract - ANSWER✔✔-Oral Cavity --> Esophagus --> stomach --> small intestine -->
large intestine
GI tract accessory glands - ANSWER✔✔-Salivary Glands in the oral cavity and the
liver, gallbladder, pancreas, in the small intestine
What are the functions of the GI Tract? - ANSWER✔✔-Digestion, Absorption, Secretion,
motility, storage, elimination and barrier
Digestion - ANSWER✔✔-reduce size of molecule and repackage
,Absorption - ANSWER✔✔-movement from GI tract to blood or lymph
Secretion - ANSWER✔✔-movement into the lumen
Motility - ANSWER✔✔-muscles mix and move contents via peristalsis
Barrier - ANSWER✔✔-between the external and internal environments
What are the goals and functions of the oral cavity? - ANSWER✔✔-Goal = food bolus
Functions - chewing, initiate digestion, swallowing
Salivary Glands features - ANSWER✔✔-Tongue, sublingual gland, submandibular
gland, lymph nodes, parotid gland
Saliva functions - 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 - ANSWER✔✔-1. Mucosa
2. Submucosa
3. Muscularis
4. Serosa
,Peristalsis - ANSWER✔✔-the process of swallowing. Esophageal sphincter makes
wave-like muscle contractions of the alimentary tract that moves food along.
Stomach Anatomy - 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 - ANSWER✔✔-form chyme (food + secretions)
Stomach functions - 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? - ANSWER✔✔-- HCl
and intrinsic factor
- Pepsinogen and gastric lipase
- mucus
- water, electrolytes, bicarbonate
Chief cells secrete pepsin. How? - 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? - ANSWER✔✔-Pepsin is an enzyme that breaks down ingested protein
into short peptides
HCl is needed to secrete pepsin. Where does it come from? - 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 - ANSWER✔✔-Histidine -(histidine decarboxylase)> Histamine
CO2 molecule is lost in this reaction
