Brainscape's Knowledge GenomeTM

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


See full index

Aa. Year 1 Questions > Gastrointestinal Physiology > Flashcards

Gastrointestinal Physiology Flashcards

1
Q

What are the pacemaker cells of the GI tract?

A

Interstitial cells of cajal which aloow the basal electrical rhythm

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

What is the gastroilieal reflex?

A

When food enters the stomach, gastrin is released which feeds-forward and prepares the small intestine for food

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

What process occurs in the digestive state?

A

Segmentation

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

What process occurs in the interdigestive (fasting) state?

A

Peristalsis

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

What is the migrating motor complex?

A

A slowly migrating wave of contraction that occurs across the whole of the small intestine

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

What inhibits the migrating motor complex?

A

Feeding
Vagal Activity
Gastrin
Cholecystokinin

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

What triggers the migrating motor complex?

A 
Motilin
Macrolide Antibiotics (mimics motilin)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is Glucose-Dependent Insulinotropic Peptide?

A

Released from K cells in response to glucose, amino acids and fatty acids
Stimulates insulin release
Inhibits gastric emptying

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

What is Glucagon-Like Peptide 1?

A

Released from L cells
Stimulates insulin secretion
Inhibits glucagon secretion
Decreases gastric emptying and appetite

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

What is Motilin?

A

Released from M cells during fasting state

Initiates Migrating Motor Complex

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

What is Ghrelin?

A

Released from Gr cells

Stimulates appetite

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

What factors enhances intestinal juice secretion?

A 
Distention
Gastrin
CCK
Secretin
Parasympathetic Nerve Activity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What facetors decreases intestinal juice secretion?

A

Sympathetic Nerve Activity

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

What is contained within intestinal juice?

A

Mucus - from Goblet Cells

Aqueous Salt - from Bases of the Crypts of Lieberkuhn

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

Where are the exocrine pancreatic secretions released from?

A

Acinar Cells

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

Where are the endocrine pancreatic secretions released from?

A

Islet of Langerhans Cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the exocrine pancreatice secretions?

A

Proteases - Trypsinogen, Chymotrypsinogen, Procarboxypeptidase A and B
Amylases - Pancreatic Amylase
Lipases - Pancreatic Lipase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Which group of enzymes are released in an inactive form from the pancreas?

A

Proteases

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

Which enzyme activates the proteases released from the pnacreas?

A

Enterokinase released from mucosal cells

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

What are the two types of digestive processes?

A

Luminal digestion

Membrane digestion

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

What is luminal digestion?

A

This occurs in the lumen. It is mediated by pancreatic enzymes.

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

What is membrane digestion?

A

This occurs on the external surface of the membrane of microvilli by enteric and absorbed enzymes

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

What is assimilation?

A

The overall process of digestion and absroption

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

Name some polysaccharides?

A

Starch

Glycogen

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

Name some oligosaccharides (3-10 simple sugars)?

A

Sucrose
Lactose
Maltose

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

Name some monosaccharides?

A

Glucose
Fructose
Galacrose

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

Which enzyme mediates conversion of polysaccharides to oligosaccharides?

A

Alpha Amylase

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

Which enzyme mediates conversion of oligosaccharides to monosaccharides?

A

Oligosaccharidases -
Lactase
Maltase
Sucrose-Isomaltase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the action of alpha amylase?

A

Breaks down linear internal alpha 1,4 linkages

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

What is the action of lactase?

A

Brakes down glucose to galactose

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

What is the action of all other oligosaccharidases?

A

Cleave the terminal alpha 1,4 linkages of maltose, maltotriose and alpha-dextrins

32
Q

Where does the absorption of the final products of carbohydrate digestion occur?

A

Duodenum and Jejunum

33
Q

How do glucose and galactose cross the apical membrane?

A

Secondary active transport mediated by SGLT1

34
Q

How does fructose cross the apical membrane?

A

Facillitated diffusion by GLUT5

35
Q

How do the monosaccharides cross the basolateral membrane?

A

Facilitated diffusion by GLUT2

36
Q

What is the process of protein digestion in the stomach?

A

HCl begins to denature proteins

Pepsin cleases the proteins into peptides

37
Q

What is the process of protein digestion in the duodenum?

A

Pancreatic proteases carry out hydrolysis

38
Q

How do amino acids cross the apical membrane?

A

There are both Na+ dependent co-transporters and Na+ independent transporters

39
Q

How do amino acids cross the basolateral membrane?

A

Movement is bidirectional to satisfy enterocytes nutritional requirements.
Na+ Independent efflux channels
Na+ dependent influx channels

40
Q

How do peptides cross the apical membrane?

A

PepT1 and SLC15A co-transporters (H+ dependent)

41
Q

How do peptides cross the basolateral membrane?

A

They are hydrolysed to amino acids within the enterocytes and are then transported across the basolateral membrane as amino acids

42
Q

How are triacylglycerols digested in the stomach?

A

By gastric lipase which is secreted in response to gastrin

43
Q

How are triacylglycerols digested in the duodenum?

A

By pancreatic lipase secreted from acinar cells in response to CCK

44
Q

What is the action of pancreatic lipase?

A

Hydrolyses TAGs at the 1 and 3 positions

45
Q

What is the role of biles salts?

A

They act as detergents to help emulsify large liquid droplets to small droplets
They increase the surface area for attack by pancreatic lipase but block access of the enzyme for TAGs

46
Q

What is colipase?

A

An amphipathic polypeptide which binds to bile salts and lipase allowing binding between lipase and TAGs

47
Q

How do fatty micelles cross the apical membrane?

A

By passive diffusion or by membrane fatty-acid translocases, fatty-acid binding protein and fatty-acid transport proteins

48
Q

What happens to long chain fatty acids within the enterocytes?

A

They are resynthesized to triglycerides in the ER and are incorportared into chylomicrons

49
Q

How is cholesterol absorbed?

A

Transport by endocytosis in clatherin coated pits by Niemann-Pick C1-Like-1 Protein (NPC1L1)

50
Q

How is Ca2+ absorbed?

A

Passive - between enterocytes

Active - Ca2+ channes (apical), Ca2+ATpase and Sodium Calcium Exchanger (basolateral)

51
Q

How is Iron reduced?

A

Only reduced Fe2+ cna be absorbed by the apical membrane therefore reduction is promoted by HCl, Vitamin C, Ferric Reductase, Gastroferrin

52
Q

How is iron absorbed?

A

Apical - DMT1
Within enterocytes - Transported by mobilferrin
Basolateral - Ferroportin 1

53
Q

What controls the ileocaecal valve?

A

Enteric Neurons
Vagus Nerve
Sympathetic Nerves
Hormonal Signals

54
Q

What is involved in the gastroileal reflex?

A

Relaxation of the ileocaecal valve/sphincter
Increased contractions of the ileum
Delivery of chyme from the lieum to the caecum

55
Q

What are the triggers for the gastroileal reflex?

A

Gastrin

CCK

56
Q

What are the primary functions of the large intestine?

A

Absorption of Na+, Cl- and H2)
Absorption of short chain fatty acids
Secretion of K+, HCO3- and mucus
Resevoir of colonic ocntents

57
Q

What mediates electroyte abosorption in the large intestine?

A

Surface epithelial cells

58
Q

What mediates ion secretion in the large intestine?

A

Crypt cells

59
Q

What secretes mucus in the large intestine?

A

Goblet cells

60
Q

What is haustration?

A

Non-propulsive segmentation

61
Q

What are peristaltic propulsive movements?

A

Mass movement

62
Q

What is defecation?

A

Periodic egestion

63
Q

What is the gastrocolic reflex?

A

Presence of food in the stomach is coupled to the mass movement reflex in the colon

64
Q

What stimulates the gastrocolic reflex?

A

Gastrin

Enteric nerve plexuses

65
Q

What provides the osmotic force for the absorption of water?

A

Na+

66
Q

What are the 5 principle mechanisms of Na+ absorption?

A 
Na+/glucose co-transport
Na+/amino acid co-transport
Na+/H+ exchange
Parallel Na+/H+ and Cl-/HCO3- exchange
Epithelial Na+ Channels
67
Q

What factors reduce Parallel Na+/H+ and Cl-/HCO3- exchange?

A

Intracellular cAMP, cGMP and Ca2+

68
Q

What regulates epithelial Na+ channels?

A

Aldosterone

69
Q

Where is Cl- secreted from?

A

Crypt cells

70
Q

What activates the CFTR protein?

A

Bacterial enterotoxins
Hormones and neuortransmitters
Immune cell products
Some laxatives

71
Q

What is the overall effect of the opening of CFTR proteins?

A

Secretory diarrhoea

72
Q

What are the main neurotransmitter systems involved in nausea and vomiting?

A

5-HT
Dopamine
ACh

73
Q

What area of the brain can cause nausea and vomiting?

A

Chemoreceptor trigger zone

74
Q

What is the action of Vasoactive Intestinal Peptide?

A

Stimulates secretion by the pancreas and intestines

Inhibits acid secretion

75
Q

Where is somatostatin released from?

A

D cells

76
Q

Where is CCK released from?

A

I cells

77
Q

Where are bile salts absorbed?

A

Terminal Ileum

Aa. Year 1 Questions (12 decks)

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