upper GI tract anatomy

Question 1

what is the gastrointestinal (GI) system

Answer 1

the system of hollow organs, tubes and support organs which facilitate the brrakdown of food to simple chemical structures to fuel cellular metabolism

Question 2

what is the GI tract seperated by

Answer 2

sphincters

Question 3

what is the main role of the stomach

Answer 3

to sterilise food

Question 4

what is the most important part of the GI tract

Answer 4

the small intestine

Question 5

what are the 5 sphincters called

Answer 5

• upper oesophageal sphincter
• lower oesophageal sphincter
• pyloric sphincter
• ileocecal sphincter
• internal and external anal sphincters

Question 6

what are the main functions of the GI tract

Answer 6

• motility
• secretion
• digestion
• absorption

Question 7

what is motility within the GI tract

Answer 7

movement of food (churning) mostly by action of smooth muscle
(ie peristalsis - allows you to direct food towards the anus)

Question 8

what is secretion within the GI tract

Answer 8

from the GI tract itself or from accessory organs as a result of stimuli (food, hormonal and/or neural)

Question 9

what is digestion within the GI tract

Answer 9

chemical breakdown of food by enzymatic digestion and mechanical breakdown of food into simple chemical building blocks which can easily cross the epithelium
(eg mastication)

Question 10

what is absorption within the GI tract

Answer 10

transfer of absorbable products of digestion into the blood or lymph to allow these simple chemical structures to facilitate cellular metabolism

Question 11

how does the basic epithelium of the GI tract contribute to its function

Answer 11

epithelium acts as a physical barrier to keep food within the lumen
allows good bacteria to stay within the tract, they also contain immune cells

Question 12

what are the 4 types of epithelia cells within the GI tract

Answer 12

• serosa
• mucosa
• submuosa
• muscularis externa

Question 13

what is the serosa

Answer 13

a squamous layer which is not present in all parts of the GI tract

Question 14

what is the mucosa

Answer 14

it is in direct contact with the lumen. responsible for protection (barrier), secretion (lubricates tract) and absorption

Question 15

what is the submucosa

Answer 15

responsible for secretion and absorption
contains meissner plexus in places (this is responsible for transmitting info between GI tract and the brain)

Question 16

what is the muscularis externa

Answer 16

responsible for motility