BIOLOGY II

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BIOLOGY II

• Gut Function Regulation
• Dr Alan Tuffery Physiology
• atuffery_at_tcd.ie
• Punctuality Mobiles

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Nutrition Excretion

• Regulation of Motility Secretion
• Digestion, Absorption Defaecation
• Mammalian Kidney Filtration, Reabsorption
  Secretion Regulation

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Useful Textbooks

• Germann Stanfield
• Principles of Human Physiology
• (612 P23 Hamilton Reserve S-LEN)
• Sherwood
• Human Physiology From Cells to Systems
• (612 M982Hamilton Reserve S-LEN)

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1. Overview of Gut

• General Function of Gut
• General structure assumed
• Accessory organs
• salivary glands, pancreas, liver
• Motility
• Secretion (e.g. pancreas)

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Gut General Functions

• Motility
• Secretion
• Digestion
• Absorption
• (Immunological)

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General structure of the gut
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Liver lobule

• Flow of nutrients
• From hepatic portal vein
• Hence gradient of stored nutrients from HPV to
  central vein
• bipolar hepatocytes

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Pancreas

• Endocrine
• Insulin,glucagon
• Exocrine
• Enzymes (acini)
• Bicarbonate (ducts)

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Motility defined

• The movement of the wall of the gut
• Peristalsis (rel. rare)
• Segmentation (main)
• Haustration (large intestine segmentation)
• NOT movement of the contents of the gut

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Motility segmentation

• Commonest
• Alternating contraction
• Mixing
• AND
• Propulsion
• Frequency decreases distally

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Motility peristalsis

• Relatively rare
• Waves of contraction
• Rapid propulsion
• clearing

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Pancreas

• Endocrine
• Insulin,glucagon
• Exocrine
• Enzymes (acini)
• Bicarbonate (ducts)

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Pancreas exocrine function

• Stimulus H
• Signal secretin
• Effector pancreatic duct cells
• NEGATIVE FEEDBACK

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Pancreas Endocrine function

• Acts to prevent rise in glucose following
  digestion/absorption

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Gut Control mechanisms