Digestive System

Question 1

What is the order & pathway of the digestive system ?

Answer 1

1. Oral cavity (mouth)
2. Pharynx
3. Esophagus
4. Stomach
5. Small intestine
6. Large intestine
7. Rectum
   * Salivary glands, pancreas, liver, & gallbladder aid in this process

Question 2

A collection of 1 hundred million neurons that govern the function of the gastrointestinal system is known as ?

Answer 2

Enteric nervous system

*Peristalsis triggered = rhythmic contractions of the gut

Question 3

The process of mechanical digestion is known as ?

Answer 3

Mastication (chewing)

Question 4

What are the different components & functions of saliva ?

Answer 4

Salivary amylase (Ptyalin): hydrolyzes starch into smaller sugars
Lipase: catalyzes hydrolysis of lipids
*Tongue forms bolus

Question 5

What are the 3 components of the pharynx ?

Answer 5

1. Nasopharynx: behind nasal cavity
2. Oropharynx: back of the mouth
3. Laryngopharynx: above vocal cords

Question 6

How is food prevented from entering the larynx when passing through the pharynx ?

Answer 6

By the epiglottis

Question 7

The rhythmic contraction of smooth muscle that propels food forward toward the stomach is called what ?

Answer 7

Peristalsis

*Reverse process = emesis (vomiting) 🤮

Question 8

What constitutes the upper esophageal sphincter ?

Answer 8

The muscles of the oropharynx (initiate swallowing)

Question 9

What constitutes the lower esophageal sphincter (cardiac sphincter) ?

Answer 9

Muscular ring that relaxes & allows passage of the bolus

Question 10

What are the 4 main anatomical divisions of the stomach ?

Answer 10

1. Fundus + body: contain mostly gastric glands

2. Antrum + pylorus: contain mostly pyloric glands

Question 11

The functions of gastric glands mainly consist of ?

Answer 11

Respond to signals from vagus nerve of parasympathetic NS

Question 12

What are the 3 different cell types of the gastric glands ?

Answer 12

Mucosal: produce bicarbonate-rich mucus that protects the muscular wall from harsh acidic & proteolytic environment
Chief: secrete pepsinogen (zymogen of pepsin)
Parietal: as HCL, cleave pepsinogen into pepsin (digest proteins by cleaving peptide bonds); also secrete intrinsic factor (glycoprotein involved in absorption of B12)

Question 13

What does pyloric glands contain ?

Answer 13

G cells: secrete gastrin (induces parietal cells to secrete more HCl & signal for stomach to contract)

Question 14

The digestion of solid food in the stomach results in an acidic semifluid mixture known as ?

Answer 14

Chyme

Question 15

Enzymes present on the surface of the duodenum that function to break down dimers & trimers of biomolecules into absorbable monomers is known as ?

Answer 15

Brush-border enzymes

Question 16

What are the different types of peptidases & what are their functions ?

Answer 16

Aminopeptidases: cleave N-terminus from peptides
Dipeptidase: cleaves peptide bonds of dipeptides to free amino acids
Enteropeptidase: critical for activation of trypsinogen to trypsin (pancreatic protease)

Question 17

Which peptide hormone causes for pancreatic enzymes to be released into the duodenum ?

Answer 17

Secretin

*Enterogastrone: slows motility through digestive tract

Question 18

Cholecystokinin (CCK) is secreted in response to chyme in the duodenum. This peptide hormone then stimulates the secretion of bile & pancreatic juices. What are the functions of bile & pancreatic juices ?

Answer 18

• It is composed of bile salts, pigments, & cholesterol
• Bile salts are derived from cholesterol & play an important role in mechanical digestion of fats & chemical digestion of lipids; emulsify (mixes) fats & cholesterols into micelles (aggregates)
• complex mixture of several enzymes in a bicarbonate-rich alkaline solution
• aids in neutralizing chyme & providing ideal environment for digestion enzymes

Question 19

The exocrine cells that produce pancreatic juices & compose the bulk of the pancreas & produce pancreatic enzymes is known as ?

Answer 19

Acinar cells

*Secrete products into major & minor duodenal papillae (empty intp duodenum)

Question 20

What connects the liver with both the small intestine & gallbladder ?

Answer 20

Bile ducts

Question 21

The liver takes up excess sugar to create what ?

Answer 21

Glycogen:: storage form of glucose

*Also stores fats as triacylglycerols

Question 22

What is the major pigment of bile ?

Answer 22

Bilirubin: byproduct of the breakdown of hemoglobin

Question 23

What does the small intestine consist of ?

Answer 23

1. Duodenum: primarily involved in digestion

2. Jejunum + Ileum: primarily involved in absorption of nutrients

Question 24

What are the 4 fat-soluble vitamins ?

Answer 24

A, K, E, D

*Everything else = water soluble

Question 25

The large intestine is primarily involved in ?

Answer 25

H2O absorption

Question 26

What are the components of the large intestine ?

Answer 26

Cecum: accepts fluid from small intestine through ileocecal valve & is site of attachment of appendix Colon: absorb H2O & salts from undigested material; concentrates remaining material to form feces Rectum: anus (internal & external sphincters)

Question 27

Which enzyme is responsible for the hydrolysis of the C-terminal on peptide bonds, aiding in the digestion of proteins ?

Answer 27

Carboxypeptidases

Question 28

Which enzyme cleaves the peptide bond @ the N-terminal, & aids in the digestion of proteins ?

Answer 28

Chymotrypsin

Question 29

Which hormone (enzyme) causes for contraction of the gallbladder ?

Answer 29

Cholecystokinin

Question 30

Which enzyme activates pancreatic digestive enzymes ?

Answer 30

Enteropeptidase

Question 31

What enzymes do each region of the digestive system produce ?

Answer 31

Mouth: amylase, lipase Stomach: Pepsin Pancreas: Trypsin, chymotrypsin, carboxypeptidases A & B, amylase, lipase Gallbladder: Bile micelles Small intestine: dipeptidases, aminopeptidases, sucrase, lactase, maltase, isomaltase

Question 32

Which enzyme produced in the duodenum activates trypsin ?

Answer 32

Enterokinase

Question 33

What facilitates fat absorption in the small intestine by breaking down large fat droplets ?

Answer 33

Bile (in liver)