BIOLOGY II
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Transcript of BIOLOGY II
SF Biology II 1
BIOLOGY IIBIOLOGY II
Gut Function & Regulation
Dr Alan Tuffery — [email protected]
PunctualityMobiles
SF Biology II 2
Nutrition & ExcretionNutrition & Excretion
•Regulation of Motility & Secretion
•Digestion, Absorption & Defaecation
•Mammalian Kidney: Filtration, Reabsorption & Secretion; Regulation
SF Biology II 3
Useful TextbooksUseful Textbooks
Germann & StanfieldPrinciples of Human Physiology(612 P23 Hamilton Reserve; S-LEN)
Sherwood Human Physiology From Cells to
Systems(612 M98*2Hamilton Reserve; S-LEN)
SF Biology II 4
1. Overview of Gut1. Overview of Gut
General Function of GutGeneral structure assumed
Accessory organs: salivary glands, pancreas, liver
Motility
Secretion (e.g. pancreas)
SF Biology II 5
Gut — General FunctionsGut — General Functions
• Motility• Secretion• Digestion• Absorption• (Immunological)
SF Biology II 7
Liver lobuleLiver lobule
• Flow of nutrients– From hepatic portal
vein
• Hence gradient of stored nutrients from HPV to central vein
• ’bipolar’ hepatocytes
SF Biology II 8
PancreasPancreas
• Endocrine– Insulin,glucagon
• Exocrine– Enzymes
(acini)
– Bicarbonate (ducts)
SF Biology II 9
Motility — definedMotility — 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
SF Biology II 10
Motility — segmentationMotility — segmentation
• Commonest• Alternating
contraction• Mixing
AND• Propulsion• Frequency
decreases distally
SF Biology II 11
Motility — peristalsisMotility — peristalsis
• Relatively rare
• Waves of contraction
• Rapid propulsion– ‘clearing’
SF Biology II 12
PancreasPancreas
• Endocrine– Insulin,glucagon
• Exocrine– Enzymes
(acini)
– Bicarbonate (ducts)
SF Biology II 13
Pancreas — exocrine functionPancreas — exocrine function
• Stimulus: H+
• Signal: secretin
• Effector : pancreatic duct cells
• NEGATIVE FEEDBACK
SF Biology II 14
Pancreas — Endocrine functionPancreas — Endocrine function
• Acts to prevent rise in glucose following digestion/absorption