Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Phase 1 > Gastrointestinal System > Flashcards

Gastrointestinal System Flashcards

1
Q

what separates the oesophagus from the pharynx?

A

upper oesophageal sphincter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what separates the stomach from the oesophagus and the small intestine?

A
  • between stomach / oesophagus: lower oesophageal or cardiac sphincter
  • between stomach / small intestine: pyloric sphincter
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

where does the small intestine terminate?

A

ileoceaecal junction (sphincter muscle)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

describe the structures of the large intestine (4)

A
  • caecum
  • appendix
  • colon: ascending, transverse, descending
  • rectum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what are the 3 main arterial supplies to the GI tract? what structures does each supply?

A
  • coeliac: liver, gall bladder, pancreas, stomach, spleen
  • superior mesenteric: pancreas, small intestine, most of the large intestine
  • inferior mesenteric: terminal portions of large intestine, rectum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

describe the organisation of the microanatomy of the gut

A

4 layers: mucosa, submucosa, muscle and serous / adventitia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

in the GI tract, what is the difference between serous and adventitial layers? what particular structures is adventitia associated with?

A
  • serous: continuous with parietal peritoneum, slippery to reduce friction
  • adventitia: fibrous connective tissue, present in oral cavity, upper oesophagus, asd. + desd. colon, rectum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

describe mucosa of the GI tract (3)

A
  • epithelial layer: type changes according to function of particular part of tract (eg. secretory, protective or absorptive)
  • lamina propia: loose connective tissue containing BVs and lymph vessels (called lacteals in small intestine)
  • muscularis mucosa / interna: smooth muscle, contracts to break down food
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

describe submucosa of the GI tract (3)

A
  • loose connective tissue
  • sometimes contains glandular structures
  • submucosal nerve plexus found here - parasympathetic neurones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

describe the layers and actions of muscularis external in the GI tract (2)

A
  • inner circular layer: prevents food travelling back (closes behind contents)
  • outer longitudinal layer: shortens and lengthens to pull contents along
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are the 2 plexi of the GI tract lining?

A
  • submucous plexus - Meissner’s

* myenteric plexus - Auerbach’s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what type of epithelium lines the mouth and oesophagus?

A

non-keratinised stratified squamous epithelium (no secretion or absorption through epithelium)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

describe the functions of mastication (4)

A
  • saliva dissolves chemicals to stimulate taste buds
  • lubricate food to ease swallowing
  • mix starch-containing foods with salivary alpha amylase
  • increase SA of food to facilitate digestion in stomach and duodenum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

describe the salivary ducts (3, with 3 descriptions)

A
  • parotid - lie in cheek, 25% of saliva, serous gland producing water saliva with increased amylase
  • submandibular - under mandible, 70%, serous and mucous gland producing more viscous saliva
  • sublingual - floor of mouth (many small ducts), 5%, mostly mucous cells producing thick, viscous mucus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

describe the 4 anatomical regions of the stomach

A
  • cardia - adj. to lower oesophageal sphincter
  • fundus - upper portion, acts a reservoir for food and swallowed air
  • corpus - main site of secretion
  • pyloric antrum - adj. to duodenum, involved in mixing of food with secretions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

describe the musculature of the stomach (3)

A
  • outer longitudinal layer and inner circular layer (as in rest of GI tract)
  • these layers are thicker in pyloric region
  • fundus and corpus contain additional oblique layer of smooth muscle below circular layer
17
Q

describe gastric mucosa (3)

A
  • thick mucous membrane, smooth when distended
  • develops rugae (folds) when empty
  • luminal surface contains gastric pits, branching from tubular-shaped glands, which reach in towards level of muscularis mucosae
18
Q

describe the 3 gastric glands, where they are found, and what they secrete (incl. cell types)

A
  • cardiac - adj. to lower oesophageal sphincter: mucous cells secrete mucus for lubrication
  • parietal - fundus and corpus: parietal cells secrete HCl, chief cells secrete pepsinogen, endocrine cells secrete somatostatin and ghrelin
  • pyloric - pylorus: chief cells secrete pepsinogen, mucous cells secrete mucus, endocrine cells secrete somatostatin and gastrin
19
Q

what are the functions of HCl in the stomach? (4)

A
  • converts pepsinogen (a zymogen) to pepsin to facilitate protein digestion
  • stimulates release of bile and pancreatic enzymes into duodenum
  • promotes absorption of some vitamins and minerals
  • kills microorganisms
20
Q

describe the production and release of bile (3)

A
  • produced in liver
  • stored in gallbladder
  • released into duodenum after meal via common bile duct
21
Q

describe bile salts (3)

A
  • derived from cholesterol - form cholic acid and chenodeoxycholic acid (bile acids)
  • conjugated with amino acids glycine and taurine to form bile salts
  • amphipathic - hydrophobic (cholesterol) component and hydrophilic (amino acid conjugate) component
22
Q

describe the function of bile salts (2)

A
  • emulsify lipid aggregates to increase surface area

* solubilisation and transport of lipids in aqueous environment

23
Q

describe the action of different pancreatic enzymes (3)

A
  • some pancreatic enzymes are secreted as active forms into duodenum (pancreatic lipase, pancreatic amylase)
  • trypsinogen is activated by brush border enzymes (enteropeptidase), and then goes on to activate more trypsinogen (autoactivation) and other zymogens
  • other proteases are also released as zymogens to prevent them from digesting the pancreas itself
24
Q

describe digestion in the mouth (mechanical digestion, carbs, proteins and lipids)

A
  • mechanical digestion via mastication
  • carbohydrates: starch broken down by alpha-amylase to maltriose, maltose and alpha-limit dextrin
  • no protein digestion
  • lipids: minor contribution though lingual lipase
25
Q

describe digestion in the stomach (mechanical digestion, carbs, proteins and lipids)

A
  • churning action
  • no carb digestion
  • proteins: HCl denatures proteins and activates pepsin which cleaves proteins into small oligopeptides
  • lipids: minor contribution through gastric lipase
26
Q

describe digestion in the duodenum (mechanical digestion, carbs, proteins and lipids)

A
  • chyme is mixed with pancreatic juice and bile (slightly alkaline to neutralise stomach acid)
  • carbohydrates: alpha-amylase, brush border disaccharidases (maltase, sucrase, lactase) producing monosaccharides
  • proteins: cleaved by trypsin, chymotrypsin and elastase to produce small peptides / dipeptides, brush border peptidases produce dipeptides / amino acids
  • lipids: pancreatic lipase digests lipids to monoglycerides and fatty acids
27
Q

describe the absorption of lipids (4)

A
  • if fatty acids are less than 12 carbons long, they enter straight into portal blood
  • if larger, triglyceride reformed into protein / lipid structure -> chylomicron
  • chylomicrons are secreted into lymphatics via lacteals
  • enter blood stream via thoracic duct
28
Q

how are monosaccharides transported on the apical and basolateral sides of small intestine epithelium?

A
  • apical: SGLT1 co-transporter (glucose, galactose), GLUT5 facilitated diffusion (fructose)
  • basolateral: GLUT2 facilitated diffusion (all 3)

Phase 1 (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions