Lecture 3-Physiology Flashcards

1
Q

Which spinal divisions are part of the sympathetic innervation to the GI tract?

A

T5-L3

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2
Q

Which spinal divisions form the greater splanchnic nerve?

A

T5-9

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3
Q

Which spinal divisions form the lesser splanchnic nerve?

A

T10-11

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4
Q

Which spinal division forms the least splanchnic nerve?

A

T12

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5
Q

True or false: sympathetic innervation in the GI tract mainly innervates blood vessels

A

TRUE

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6
Q

Which nerve provides the major parasympathetic innervation to the GI tract?

A

Vagus nerve

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7
Q

True or false: left vagus nerve becomes posterior and right vagus nerve becomes anterior as the foregut rotates

A

FALSE - other way round

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8
Q

Which part of the GI tract do the parasympathetic fibres innervate?

A

Smooth muscle, endocrine and secretory parts

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9
Q

True or false: the enteric nervous system can operate independently of the ANS

A

TRUE

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10
Q

What are the two main plexuses of the enteric nervous system?

A

1) submucosal (Meissner’s)

2) myenteric (Auerbach’s)

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11
Q

Give an example of a paracrine peptide and state where it’s found and what it does

A
  • Somatostatin
  • D cells in antrum of stomach and pancreas
  • Stimulated by H+ in stomach and inhibits G cells and histamine release
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12
Q

Give an example of a neurocrine peptide, where it is found and what it does

A
  • Gastrin releasing peptide (GRP)
  • Released by vagus nerve
  • Increases release of gastrin from G cells
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13
Q

What are the two families of GI hormones?

A

Gastrin family

Secretin family

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14
Q

What are the two hormones in the GI family?

A

Gastrin

Cholecystokinin

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15
Q

What does gastrin bind to and what does it do?

A

CCK receptor

Increases gastric acid secretion

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16
Q

Which cells produce cholecystokinin (CCK) and where?

A

I cells in duodenum and jejunum

17
Q

What does CCK do?

A

Increases pancreatic/gallbladder secretions

Relaxes muscular sphincter where biliary tree enters 2nd part of duodenum

18
Q

What stimulates CCK?

A

Fat and protein

19
Q

Which two hormones are in the secretin family?

A

Secretin

Gastric inhibitory peptide (GIP)

20
Q

Which cells produce secretin and where?

A

S cells in duodenum

21
Q

What stimulates secretin?

A

H+ and fatty acids

22
Q

What does secretin do?

A

Increases HCO3-

Decreases gastric acid

23
Q

Where is GIP produced?

A

Duodenum and jejunum

24
Q

What stimulates GIP?

A

Sugars
AA
Fatty acids

25
Q

What does GIP do?

A

Increases insulin

Decreases gastric acid

26
Q

Where can pain in foregut structures be felt?

A

Epigastric region

27
Q

Where can pain in midgut structures be felt?

A

Periumbilical region

28
Q

Where can pain in hindgut structures be felt?

A

Suprapubic region

29
Q

What is peristalsis?

A

Propulsion of contents in one direction

30
Q

What is segmentation?

A

Contraction splits contents then relaxes, mixes contents

31
Q

What is paralytic ileus?

A

Loss of GI contractility

32
Q

What is achalasia?

A

Failure of LOS to relax -> dysphagia

33
Q

What is Hirschsprung’s disease?

A

Lack of myenteric/submucosal plexuses

34
Q

What are the major types of GI secretions and what are their functions?

A
  • stomach acid: protein digestion, activates enzymes, infection barrier
  • HCO3-: neutralise food
  • emulsifiers: bile salts to increase SA of lipids
  • mucus: lubrication, protects against acidity of stomach, protects against bacteria in SI, harbours bacteria in LI
  • enzymes: to break down protein, fat and carbs