Brainscape's Knowledge GenomeTM

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


See full index

Gastrointestinal > Physiology > Flashcards

Physiology Flashcards

1
Q

how to calculate BMI & ranges

A

weight/(height 2)

<25= norm, <29.9=overweight, <39.9= obese, >40=morbidly obese

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

what is a tx for obesity

A

recombinant lectin therapy, drugs, surgery e.g. gastric by-pass surgery

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

what 3 things regulate satiety?

A

enterogastrones
hypothalamus
apetite controllers

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

what are 3 examples of enterogastrones

A

CCK, glucagon-like-peptide 1, Gherlin

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

what is 1 appetite controller that inc food intake and 1 that decreases food intake

A

glutamate

monoamines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

other than satiety signalling, what two other mechanisms influence ANS and neuroendocrine activity?

A

adiposity -ve feedback signalling

food reward

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

what are the signalling molecules for adiposity -ve feedback and food reward pathways?

A
  • leptin & insulin

- dopamine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what does leptin mimic?

A

fullness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what does insulin do

A

inc energy burn

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are the 2 mechanical activities of the 2 areas of the stomach?

A

orad stomach- tonic

caudad stomach- phasic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

3 points of tonic activity in stomach…

A

relaxation driven by vagus to to accommodate mass
tonic contractions are weak due to thin muscle
NO SLOW WAVES

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

2 points of phasic activity in stomach…

A

intermittent contractions from mid stomach to gastro-duodenal junction propelling food through pylorus
CONSTANT SLOW WAVES

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

what is retropulsion?

A

inc velocity of contractions towards junction to overtake movement of chyme that rebounds against stomach

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

why is strength of antral waves important

A

determines how much chyme escapes through pyloric sphincter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is the strength of antral waves determined by?

A

gastric factors: proportional to volume & viscosity of chyme
duodenal factors: neural (enterogastric reflex dec strength) & hormonal (enterogastrones)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are the 2 types of gastric gland?

A 
oxyntic glands (proximal 2/3rds of stomach) 
pyloric glands (distal 1/3rd of stomach (near pylorus))
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what 5 secretions do oxyntic glands secrete & what does each do

A 
histamine (stimulates HCl)
HCl (pepsinogen>pepsin)
pepsinogen 
intrinsic factors (vitB12 absorption)
mucous (lubrication)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what 3 secretions do pyloric glands secrete & what does each do?

A

gastrin (HCl secretion)
somatostatin (inhibits HCl)
mucous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what are the main secretagogues of HCl and by which method do they secrete?

A

ACh, Gastrin, Histamine

direct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is the indirect mechanisms of HCl secretion?

A

stimulation of ECL cells > release histamine > HCl secretion via signal transduction pathways

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what are 2 substances that oppose histamine

A

somatostatin & prostaglandins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what are the 3 phases in which the stomach secretes its secretions?

A

cephalic: prepares stomach for food. vagus stimulates parietal cells
gastric: food in stomach distending it and activating acid secretion
intestinal: food has left

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

how are gastric secretions inhibited?

A

cephalic: vagal activity dec after eating
gastric: pH falls after emptying so somatostatin & prostaglandin E2 inc
intestinal: factors dec motility also dec secretion e.g. enterogastrones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what does small intestine secrete?

A

mucous & aqueous salts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what are the 2 phases of small intestine motility?

A

segmentation: contraction & relaxation of circular muscle mixing chyme
peristalsis: few localised strong contractions and migrating motor complex (MMC). clears SI of debris

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what determines strength of segmentation contractions

A

para & sympathetic activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

True/False…

peristalsis is promoted by feeding

A

False…

peristalsis promoted by motilin, inhibited by feeding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what are 6 secretions of the small intestine & their function?

A 
gastrin (stimulates HCl)
secretin (HCO3- secretion) 
CCK 
GIP (insulin release- inhibits gastric emptying)
GLP-1 (insulin release)
Motilin (MMC initiation)
Gherlin (apetite)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what 4 things does CCK do?

A

inhibits gastric emptying
secretes pancreatic digestive enzymes
ejection of bile into duodenum
potentiates secretin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what endocrine function does the pancreas have?

A

insulin, glucagon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what exocrine function does the pancreas have?

A

digestive enzymes, aqueous salts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what do duct cells do?

A

release alkaline solution to neutralise acidic chyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what do acinar cells do?

A

store pancreatic enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

name an example of a pancreatic protease, amylase, lipase ?

A

protease: trypsinogen
amylase: pancreatic amylase
lipases: pancreatic lipase

35
Q

True/False…

pancreatic enzymes are inactive in pancreas?

A

True…

inc Ca2+ cause them to migrate to duodenum where become active

36
Q

what controls pancreatic secretion in each gastric phase?

A

Cephalic: vagal stimulation of acinar cells
Gastric: distention stimulates pancreatic cells
intestinal: acid in lumen causes secretin release & fat/ protein in lumen cause CCK release= digestive enzyme release

37
Q

what 3 anatomical structures are found in large intestine?

A

caecum, appendix, colon

38
Q

what does the caecum do?

A

receives undigestible residues from terminal ileum

39
Q

what does appendix do?

A

has extensive lymphoid tissue connected to caecum via appendices orifice

40
Q

what does colon do?

A

absorbs Na+/Cl and H2O to condense ileocaecal content into stool. also secretes K+, HCO3-, mucus.

41
Q

which steroid hormone causes inc Na+ absorption and K+ secretion?

A

Aldosterone

42
Q

what are the 3 cells of the colon and their function?

A

colonocytes: mediate electrolyte absorption
crypt cells: mediate ion secretion
goblet cells: secrete mucous and proteins

43
Q

what are the 2 motility mechanisms of the large intestine?

A

Haustration: formation of haustra from contraction of circular muscle
Mass Movement: simultaneous movement of ascending & transverse colon driving faeces into rectum

44
Q

what causes defection?

A

rectal stretch

45
Q

what are the large intestine secretions?

A

bacteria that synthesise vitK and free fatty acids

46
Q

how are carbs digested?

A

starch> oligosaccharides> monosaccharides

47
Q

what are oligosaccharides?

A

membrane proteins that catalyse by cleavage of oligomers to monosaccharides e.g. glucose

48
Q

how does amylase work?

A

breaks down linkages in starch

49
Q

describe absorption of carbs

A

products of digestion transferred across apical and basolateral membrane of enterocytes

50
Q

where are monosaccharides (glucose, fructose and galactose) absorbed?

A

duodenum & jejunum

51
Q

what transmembrane proteins allow entry to enterocyte?

A

glucose & galactose- SGLT1

fructose= GLUT5

52
Q

what transmembrane protein allows exit from enterocyte?

A

GLUT2 for all

53
Q

True/False…

proteins digested by gastric and pancreatic digestion

A

True

54
Q

describe the gastric element of protein digestion…

A

HCl denatures proteins in stomach

55
Q

describe the pancreatic element of protein digestion…

A

pancreatic proteases, some of which present in duodenum and some in brush border and cytoplasm

56
Q

True/False…

proteases at brush border break down small oligopeptides (di & tripeptides)

A

False….
brush border proteases break down large oligopeptides.
proteases in cytoplasm break down small peptides

57
Q

how are proteins absorbed?

A

sigle AAs: Na+ dependent co-transporters for apical & basolateral membranes
large AAs: @ apical membrane= H+ dependent mechanisms. @ basolateral membrane= Na+ dependent system

58
Q

what happens to proteins in enterocytes?

A

become hydrolysed

59
Q

what is problematic about fat digestion

A

fats are insoluble in water so have to be converted into an emulsion

60
Q

how are fat emulsions stabilised

A

addition of amphiphilic molecules that form a surface layer on droplets

61
Q

what is the gastric phase of lipid digestion?

A

lipases secreted in response to gastrin

62
Q

what is the pancreatic phase of lipid digestion?

A

pancreatic lipase secreted in response to CCK

63
Q

how do bile salts facilitate digestion of fats?

A

released into duodenum in response to CCK to help emulsify large lipids to small ones

64
Q

what does colipase do?

A

binds to pancreatic lipase and bile salts allowing lipase access to tri and di glycerides

65
Q

what are the final products of fat digestion stored and released in…

A

micelles

66
Q

how are fats absorbed?

A

free fatty acids and monoglycerides are transferred from micelles to apical membrane and enter enterocyte

67
Q

through what mechanisms do fats enter enterocytes

A

passive diffusion, fat translocases and fatty acid binding proteins

68
Q

how do short and medium fatty acids exit cell?

A

exit enterocyte via basolateral membrane and enter villi caps

69
Q

what happens to long chains and monoglycerides?

A

are resynthesized into triglycerides in the endoplasmic reticulum and are incorporated into chylomicrons

70
Q

What does iron have to be converted to to pass into enterocyte?

A

from Fe3+ to Fe2+ by HCl

71
Q

how is vit B12 digested and absorbed?

A

stomach acid isolates protein B12 from protein, protein digested and heptacorin binds to B12 which releases IFs, B12 binds to IF and absorbed by terminal ileum

72
Q

what happens to fat soluble vitamins

A

incorporated into micelles > diffuse into enterocyte > incorporated into chylomicron or VLDLs

73
Q

how do water soluble vitamins enter enterocytes

A

via Na+ transport

74
Q

what does reabsorption of Na+ provide?

A

the osmotic force that drives reabsorption of water

75
Q

how is Na+ absorbed?

A

Na+/glucose co-transport

Na+/amino acid co-transport

76
Q

what does Na+ transport provide?

A

a transepithelial potential that drives Cl- absorption

77
Q

what type of Na+ exchange is present in jejunum and is stimulated by alkaline lumen?

A

Na+/H+ exchange

78
Q

what type of Na+ exchange is 1y mode of Na+ absorption in inter-digestive periods and occurs in ileum and proximal colon?

A

parallel Na+/H+ and Cl-/HCO3- exchange

79
Q

what type of Na+ exchange mediates Na+ absorption in distal colon and is inc by aldosterone and regulated by cAMP and cGMP?

A

epithelial Na+ channels

80
Q

how is Cl- absorbed?

A

lumen’s -ve potential due to Na+ transport

81
Q

how is Cl- secreted?

A

crypt cells have

  • Na+/K+ ATPase pump
  • Na+/K+/2Cl- co-transporters
  • K+ channels
82
Q

what happens if there is low intracellular Na+?

A

inward movement of Na+, K+ and Cl- occurs via NKCC1

83
Q

how does the body deal with inc K+ and Cl- intracellularly due to NKCC1 system?

A
  • K+ recycled via K+ channels
  • inc intracellular Cl- provides gradient for Cl- to exit via CFTR on apical membrane
  • CFTR activated via hormones, NTs etc

Gastrointestinal (24 decks)

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