Gastric Motility and Pancreatic Function Flashcards

1
Q

Describe the direction of motion of peristaltic waves in the stomach

A

From body to antrum

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2
Q

Describe the musculature of the the body of the stomach?

A

Thin muscle therefore weak contraction and no mixing

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3
Q

Describe the musculature of the antrum

A

Thicc powerful muscle therefore powerful contraction causing contents to mix

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4
Q

What is the process of mixing and emptying of the stomach?

A
  1. Mixing
  2. Contraction of the pyloric sphincter
  3. Small quantity of chyme (gastric contents) enters duodenum
  4. Further mixing as astral contents is forced back towards body
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5
Q

How many contracts are there of the stomach per min on average?

A

3

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6
Q

How are the slow depolarisations achieved?

A

Spontaneous depolarisation/repolarisation conducted through gap junctions along longitudinal muscle - slow wave polarisation sub-threshold requires further depolarisation to induce contraction

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7
Q

Motility is under neural and hormonal control - outline three stimuli

A

Gastrin and distention of stomach wall induce long/short reflexes to increase contraction

Fat/amino acid/hypertonicity in duodenum inhibit contraction

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8
Q

What salt is responsible for neutralisation of gastric acid?

A

Bicarbonate (HCO3)

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9
Q

What glands secrete bicarbonate?

A

Brunner’s Gland duct cells (submucosal glands)

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10
Q

Acid in the duodenum triggers what three responses?

A

Long (vagal) and short (ENS) reflexes alongside secretin secretion from S cells which all cause HCO3 release from liver and pancreas

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11
Q

What are the three parts of the pancreas?

A

Head
Body
Tail

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12
Q

Where is the head of the pancreas located?

A

Within the curvature of the duodenum

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13
Q

Describe the endocrine functions of the pancreas

A
Pancreatic islets (of Langerhans) control secretion of insulin and glucagon 
Also Somatostatin which helps to control insulin and glucagon
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14
Q

Describe the exocrine functions of the pancreas

A

Acinar cells arrange in lobules contain digestive enzyme precursors (zymogens)

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15
Q

Why are digestive enzyme stored in the acinar cells as precursors?

A

To avoid autodigestion

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16
Q

What enzyme converts trypsinogen into trypsin?

A

Enterokinase

17
Q

What is the role of trypsin?

A

Converts all other zymogen into their active forms

18
Q

Outline the organisation of the pancreatic tubing

A

Lobules of acinar cells connected by intercalated discs - intralobular ducts - interlobular discs - Main pancreatic duct - common bile duct - Heaptopancrearttc ampulla- Duodenum

19
Q

What is the other name for the heptopancreatic ampulla?

A

Sphincter of Oddi

20
Q

What other tube is located in the duodenum?

A

Accessory pancreatic duct

21
Q

What is the action of proteases?

A

Cleaves peptide bonds

22
Q

What is the action of nucleases?

A

Hydrolyse DNA/RNA

23
Q

What is the action of Elastases?

A

Collagen digestion

24
Q

What is the action of phosphlipases?

A

Digests phospholipids into fatty acids

25
Q

What is the action of lipases?

A

Digests TAGs to fatty acids and glycerol

26
Q

What is the action of alpha-amylase?

A

Digests starch to maltose and glucose

27
Q

How is bicarbonate secretion regulated?

A

Secretin

28
Q

What is secretin released in response to?

A

Acid in the duodenum

29
Q

What regulates the secretion of zymogens?

A

Secretion of CCK

30
Q

What is CCK released in response to?

A

Fats/amino acids in the duodenum