Digestive System

Question 1

What are the 6 main processes of Digestion?

Answer 1

Ingestion
Secretion
Mixing and propulsions
Digestion
Absorption
Defecation

Question 2

What organs are used in the process of Digestion?

Answer 2

Mouth
Pharynx
Oesophagus
Liver
Stomach
Duodenum
Pancreas
Gall Bladder
Traverse colon
Descending/ascending colon
sigmoid colon
cecum
rectum
anus
jejunum
ileum

Question 3

What are the 4 different layers of the GI Tract?

Answer 3

submucosa
mucosa
muscularis
serosa

Question 4

What does the mucosa contain?

Answer 4

epithelium
areolar connective
tissue
muscle layers

Question 5

What does the muslularis contain?

Answer 5

circular muscle
longitudinal muscle

Question 6

What is the Pharynx?

Answer 6

A funnel shaped tube composed of skeletal muscle and lined my mucous membrane

Question 7

What is the Esophagus?

Answer 7

muscular tube that connects the pharynx to the stomach

Question 8

What happens in the stages of swallowing?

Answer 8

1. the tongue shapes the lubricated food and moves it to the back of the oral cavity
   - the tongue rises against the palate and closes the nasopharynx
   - the uvula and soft palate seal off the naval cavity
   - the epiglottis covers the larynx (breathing is temporarily interrupted)
2. at each end of the oesophagus, the muscularis forms 2 sphincters:
   - upper oesophageal sphincter (consisting of skeletal muscles)
   - lower oesophageal sphincter (smooth muscle)
3. swallowing moves a bolus from the mouth to the stomach (via peristalsis)
   voluntary stage - mouth to oropharynx
   involuntary stage - pharyngeal stage

Question 9

What does the stomach connect?

Answer 9

oesophagus to duodenum

Question 10

what are the 4 regions of the stomach?

Answer 10

• cardia
• fundus
• body
• pylorus

Question 11

What is rugae?

Answer 11

folds in the stomach lining, its surface is made up of epithelial cells, it has glands that produces mucous, hydrochloric acid, pepsin, intrinsic factors (Intrinsic factors include the genetic, physiological, and pathological characteristics of an individual) and gastrin

Question 12

What is mechanical digesiton?

Answer 12

mixing waves that macerate food and mix it with gastric juice forming chyme

Question 13

Where is the pancreas?

Answer 13

lies behind the stomach

Question 14

What does the pancreas secrete and where do the secretions go?

Answer 14

secretes pancreatic juice that contains:
- enzymes
- proteins
- triglycerides
- nucleic acids
the secretions pass from the pancreas to the duodenum

Question 15

What is the relationship between the liver and the gallbladder?

Answer 15

• the gallbladder is located in a depression under the liver
• it stores and concentrates bile produced by the liver
• bile contributes to digestion by emulsifying lipids

Question 16

What are the functions of the liver?

Answer 16

• secretion of bile
• phagocytosis of bacteria
• carb, lipid, protein metabolism
• processing of drugs and hormones
• excretion of bilirubin
• storage of vitamins and activation of vitamin D

Question 17

What is the average length and width of the small and large intestines?

Answer 17

small intestine:
- 1 inch in diameter and 10 ft in length
large intestine:
- 2.5 inches in diameter and 5 ft in length

Question 18

What is the structure of the small intestine?

Answer 18

• extends from the ileocecal sphincter to the pyloric sphincter
• divided into the duodenum, jejunum, ileum
• microvilli, villi and circular folds provide a large surface area

Question 19

What is the structure of the large intestine?

Answer 19

• extends from ileocecel sphincter to the anus
• includes cecum, colon, rectum and anal canal
• divided into ascending, transverse, descending and sigmoid portions

Question 20

What are the 3 phases of digestion?

Answer 20

• cephalic phase
• gastric phase
• intestinal phase

Question 21

What happens in the cephalic phase?

Answer 21

• smell, sight, sound or thought of food activates neutral centers in the brain
• salivary glands secrete saliva and gastric glands secrete gastric juice

Question 22

What happens in the gastric phase?

Answer 22

• presence of food in stomach causes gastric phase
• promotes gastric juice secretion + gastric motility
• pyloric sphincter relaxes which promotes gastric emptying

Question 23

What happens in the intestinal phase?

Answer 23

• begins when food enters small intestine
• gastric motility and secretion decrease
• prevents Small intestine from being overloaded with more chyme it can handle
• all coordinated by hormones secretin and cholecystokinin

Question 24

Gastrin?
Where is it produced?
What is its stimulant?
What is its action?

Answer 24

Produced:
- stomach mucosa (pyloric region)
Stimulant:
- stretching of the stomach
- partially digested proteins and caffeine in stomach
- high pH of stomach chyme
Action:
- stimulates secretion of gastric juice
- increases motility of GI tract
- relaxes pyloric sphincter

Question 25

Secretin? Where is it produced? What is its stimulant? What is its action?

Answer 25

Produced: - intestinal mucosa Stimulant: - acidic chyme that enters the small intestine Action: - stimulates secretion of pancreatic juice rich in bicarbonate ions

Question 26

Cholecystokin? Where is it produced? What is its stimulant? What is its action?

Answer 26

Produced: - intestinal mucosa Stimulant: - amino acids and fatty acids in chyme in small intestine Action: - inhibits gastric emptying - stimulates secretion of pancreatic juice rich in digestive enzymes - causes ejection of bile from gallbladder - induces a feeling of satiety (feeling full to satisfaction)

Question 27

Where is the fundus located?

Answer 27

it is the rounded portion of the stomach superior and to the left of the cardia