L21 - GI Tract Structure Flashcards
What is the GI system?
A network of organs and specialised cells - enable you to transform the food you eat into the energy and nutrients required for life
What are the different parts of the GI tract? (6)
- mouth
- oesophagus
- stomach
- small intestine
- large intestine
- anus
What are the accessory organs in the GI tract? (4)
- salivary glands
- liver
- gallblader
- pancreas
What is the mesentery?
Membranous tissue that surround organs of the GI tract
What does the mesentery do? (2)
- holds intestines in place
- provides blood vessels and lymphatics
What are the different parts of the mouth? (4)
- teeth
- tongue
- mucous membranes
- pharynx and epiglottis
What is the main function of the mouth?
To chew food
What is the pharyn and epiglottis and their function?
Muscular flaps in the throat
- prevents food travelling to the lungs
What is the oesophagus?
Tube like structure
What does the oesophagus do?
Involuntary movement of food bolus
- transports food bolus to the stomach
What does the stomach do? (3)
- mixing
- protein digestion
- fat emulsification
What does the stomach contain? (2)
- HCl
- pepsin
What are the different layers of the stomach wall? (4)
- mucosa
- submucosa
- muscularis externa
- serosa
What are the different types of cell types in the stomach wall? And what do they secrete? (6)
- 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
What is the small intestine? (2)
Longest part of the GI tract
- main site of absorption
- primary site of breakdown (CHO, proteins, fats)
What are the 3 section of the SI?
- duodenum
- jejunum
- illeum
What are the different cells in the SI? And what do they do? (4)
- absorptive cells - absorbs nutrients
- goblet cell - secretes mucus
- enteroendocrine cell - secretes hormones: secretinm chlolecystokinin)
- paneth cell - secretes lysozymes, capable of phagocytosis
What is the purpose of the villus? (2)
- increase SA
- absorption
What are the crypts of lieberkuhn?
Invaginations formed between the villi
What are the cells in the crypts of lieberkuhn and what are their function? (3)
- paneth cells - defensins, antimicrobial, lysosymes, phagocytic
- stem cells - regeneration
- goblet cells - mucous
What is the function of the large intestine? (4)
- water and ion conservation
- bulk movement of faeces
- storage
- defaecation
What are the purpose of the salivary glands? (3)
- lubrication - mucus
- protection - thiocyanate, lysosymes
- digestion - amylase, lipase
What are the different salivary glands? (3)
- parotid gland
- submandibular gland
- sublingual gland
What are the functions of the liver? (2)
- bile production
- excretion