Flashcards
Gastrointestinal Tract
Cards in this deck (22)
- 1What are the 6 key features of the gastointestinal tract?Ingestion
Secretion
Mixing and Propulsion
Mechnical and Chemical digestion
Absorption
Defaecation - 2What are the layers of the gut wall?Mucosa
Submucosa
Muscularis Externae
Serosa
Adventitia - 3What are the tissues found in the m usoca?Mucous membrane: lines cavities open to exterior
Epithelium: stratified squamous (mouth, oesophagus and anus) tough for protection. Simple columner (remainder) secretes enzymes and abrobs nutrients)
Lamina propria: thin layer of loose connective tissue. Route by which nutrients are absorbed. Supports epithelium
Muscularis Mucosae: thin layer of smooth muscle, carses folds to form in mucosal layer, increases local movements increaseing absorption of nutrients with exposure to new surface - 4What are the tissues found in the sub-mucosa?Loose connective tissue
Submucosal Plexus: stimulates secretion from epithelial intestinal glands, absent in oesophogus and stomach - 5What are the tissues found in the muscularis externa?Skeletal muscle: voluntary contol in mouth, pharynx, upper oesophagus and anus, control over swallowing and defecation
Smooth muscle: involuntary cocntrol, inner circular fibres and outer longitudinal fibres, mixes crushes and propels food along by peristalsis
Myenteric plexus: extensive parasympatheic and sympathetic innervation of curcular and longitidinal smooth muscle layers, controls gut motility - 6What is the arrangement of tissues within the oesophagus?Muscular trube that transports from mouth to stomach
Nonkeratinsed stratfifed squmous epithleium
Submucosa contains oeosophagal flands which facilitate transport and protect mucosa
In lamina propria near stomach are oesophageal cardiac glands that secrete mucous - 7What is the arragenment of tissues within the stomach?Begins at end of oesophagus
Ends at pyloric sphincter
Contain regae: allows expansion
Mucosa consists of surface epithelium which invaginates into lamina propria forming gastric pits
Simple columnar epithelium covering surface and lining of pits for protection - 8What is the function of mucous cells?Secrete mucous to protect stomach wall from being digested by stomach acid
- 9What is the function of parietal cells?Mainly found in upper regions of gastric glands
Secrete H+ and Cl+ which combine to form HCl
Secrete intrinsic factor
Secretory activity initiated through variety of mechanisms e.g. histamine - 10What is the function of Chief cells?Mainly found in lower region of glands
Protein synthesising and exporting cell
Granules contain inactive pepsinogen
Converted into pepsin in presence of HCl
Also produce lipase - 11Why does the stomach not digest itself?Protected in 3 ways
Mucous coat: resists action of acids and enzymes
Epithelial cell replacement: cells are replaced every 3-6 days
Tight junctions: epithelial cells are joined by tight junctions which prevent gastric juice from seeping between them - 12What can the stomach absorb?Small amount of water, ions and short chain fatty acids
Stomach not designed for absorbing unlike small intestine - 13What is the arrangement of tissues within the small intestine?3 Parts: Duodenum (5%)
Jejunum (40%)
Ileum (60%)
Structures increasing SA: plica curcularis: 1cm tall folds containing part of submuscoa, villi: 1mm tall contains vascular capillaries and lacteals, microvilli: cell surface feature known as brush border - 14What is the function of enterocytes?Tall columnar cells, absorb nutrients and secrete enzymes which bind to microwilli aiding in breakdown of macronutrients for easy absorption
- 15What is the function of goblet cells?Interspersed between enterocytes
Produce mucins
Protect against acidic contents, lubrication of lining of GIT - 16What is the function of Paneth cells?Contains lysozyme which has antibacterial activity
- 17What is the function of enteroendocrine cells?Secrete a variety of hormones with a variety of actions,
- 18What is the arrangement of tissues within the large intestine?Caecum, colon, rectum and anal canal
No villi
Simple columnar epithelium with numerous goblet cells - 19What is the function of the liver?To act as the interface between digestive system and blood
Contains hepatic lobules - 20What are the histological features of the liver?
- 21What is the structure and function of the gall bladder?Bile storage
Hollow pear shaped organ divied into fundus, body and neck - 22What is the structure and function oft he pancreas?Consists of head, body and tail
Endocrine: pancreatic islets produce insluin, glucagon and somatostatin
Exocine: acini form lobules separated by septa, produce pancreatic juice
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- University Biology (Year 1 Semester 1) Flashcards on Gastrointestinal Tract, created by Hannah Waters on 23/06/2016.
- Created by
- Hannah Waters · Jun 2016
- Updated
- Feb 4, 2018
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