L21 - GI Tract Structure

Question 1

What is the GI system?

Answer 1

A network of organs and specialised cells - enable you to transform the food you eat into the energy and nutrients required for life

Question 2

What are the different parts of the GI tract? (6)

Answer 2

• mouth
• oesophagus
• stomach
• small intestine
• large intestine
• anus

Question 3

What are the accessory organs in the GI tract? (4)

Answer 3

• salivary glands
• liver
• gallblader
• pancreas

Question 4

What is the mesentery?

Answer 4

Membranous tissue that surround organs of the GI tract

Question 5

What does the mesentery do? (2)

Answer 5

• holds intestines in place
• provides blood vessels and lymphatics

Question 6

What are the different parts of the mouth? (4)

Answer 6

• teeth
• tongue
• mucous membranes
• pharynx and epiglottis

Question 7

What is the main function of the mouth?

Answer 7

To chew food

Question 8

What is the pharyn and epiglottis and their function?

Answer 8

Muscular flaps in the throat
- prevents food travelling to the lungs

Question 9

What is the oesophagus?

Answer 9

Tube like structure

Question 10

What does the oesophagus do?

Answer 10

Involuntary movement of food bolus
- transports food bolus to the stomach

Question 11

What does the stomach do? (3)

Answer 11

• mixing
• protein digestion
• fat emulsification

Question 12

What does the stomach contain? (2)

Answer 12

• HCl
• pepsin

Question 13

What are the different layers of the stomach wall? (4)

Answer 13

• mucosa
• submucosa
• muscularis externa
• serosa

Question 14

What are the different types of cell types in the stomach wall? And what do they secrete? (6)

Answer 14

• mucous neck cell - mucus, protects lining
• parietal cells - HCl, intrinsic factor
• enterchromaffin-like cell - histamine
• chief cells - pepsin(ogen), gastric lipase
• D cells - somatostatin, inhibits acid
• G cells - gastrin, stimulates acid

Question 15

What is the small intestine? (2)

Answer 15

Longest part of the GI tract
- main site of absorption
- primary site of breakdown (CHO, proteins, fats)

Question 16

What are the 3 section of the SI?

Answer 16

• duodenum
• jejunum
• illeum

Question 17

What are the different cells in the SI? And what do they do? (4)

Answer 17

• absorptive cells - absorbs nutrients
• goblet cell - secretes mucus
• enteroendocrine cell - secretes hormones: secretinm chlolecystokinin)
• paneth cell - secretes lysozymes, capable of phagocytosis

Question 18

What is the purpose of the villus? (2)

Answer 18

• increase SA
• absorption

Question 19

What are the crypts of lieberkuhn?

Answer 19

Invaginations formed between the villi

Question 20

What are the cells in the crypts of lieberkuhn and what are their function? (3)

Answer 20

• paneth cells - defensins, antimicrobial, lysosymes, phagocytic
• stem cells - regeneration
• goblet cells - mucous

Question 21

What is the function of the large intestine? (4)

Answer 21

• water and ion conservation
• bulk movement of faeces
• storage
• defaecation

Question 22

What are the purpose of the salivary glands? (3)

Answer 22

• lubrication - mucus
• protection - thiocyanate, lysosymes
• digestion - amylase, lipase

Question 23

What are the different salivary glands? (3)

Answer 23

• parotid gland
• submandibular gland
• sublingual gland

Question 24

What are the functions of the liver? (2)

Answer 24

• bile production
• excretion

Question 25

What is the function of the gallblader? (2)

Answer 25

- concentrating reservoir for bile - deliver bile to the deodenum in response to meals

Question 26

What is the function of the pancreas? (2)

Answer 26

- makes enzymes to digest proteins, fats, and CHO - produces the hormones insuling and glucagon

Question 27

What are the functions of the GI system? (6)

Answer 27

- ingestion - secretion - movement - digestion - absorption - excretion

Question 28

What is ingestion?

Answer 28

The process of taking in food, drink, through the mouth

Question 29

What is secretion?

Answer 29

The release of substances that contribute to digestion

Question 30

What are the different types of movement? (2)

Answer 30

- segmentation - peristalsis

Question 31

What is digestion?

Answer 31

Breakdown of food into smaller component that can be absorbed into the bloodstream

Question 32

What are the types of digestion? (2)

Answer 32

- mechanical digestion - chemical digestion

Question 33

What is mechanical digestion? (3)

Answer 33

Physically breaking down food substances into smaller particles - mastication - peristaltic contractions - gastric acids

Question 34

What is chemical digestion?

Answer 34

Use of enzymes to breakdown food

Question 35

What are the products to the breakdown of these particles? (3)

Answer 35

- Fats -> FA and monoglycerides - Nucleic acids -> nucleotides - Polysaccharides, CHO sugars -> monosaccharides - Proteins -> amino acids

Question 36

What is absorption?

Answer 36

The process through which nutrients, water and electrolytes enter the blood

Question 37

What is excretion?

Answer 37

The process by which metabolic waste is eliminated from the body

Question 38

What is the role of the GI tract in immune function? (3)

Answer 38

- first line of defence against pathogens - divers microbiome that contributes to immune regulation - gut-resident immune cells

Question 39

What does the microbiome prevent?

Answer 39

Overgrowth of harmful bacteria

Question 40

What do cells secrete in terms of the immune function? (2)

Answer 40

- mucus - antimicrobial peptides