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41 Cards in this Set
- Front
- Back
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Where is secretin produced?
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Duodenum
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What stimulates the action of secretin?
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Acid (H+ ions) in duodenum
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What are the effects of secretin?
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Bicarbonate release from pancreatic duct cells
Inhibits gastric secretion in stomach Enhances effects of CCK Promotes growth and maintenance of pancreas |
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Where is CCK (cholecystokinin) produced?
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Duodenum
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What stimulates the action of CCK?
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Fatty acids and amino acids in the duodenum
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What are the effects of CCK?
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Stimulates acid secretion from pancreatic acinar cells
Contracts the gall bladder Opens Sphincter of Oddi Inhibits gastric emptying Promotes pancreas growth and maintenance Enhances effects of secretin Induces satiety |
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Where is gastrin produced?
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Distal part of stomach
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What is the stimulus for gastrin release?
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Amino acids and peptides in stomach
Gastric distension |
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What are the effects of gastrin?
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Stimulates acid secretion in stomach
Promotes growth of mucosa |
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Where is gastric inhibitory peptide (GIP) produced?
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Proximal small intestine
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What is the stimulus of GIP?
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Amino acids, fats and glucose in small intestine
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What are the effects of GIP?
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Reduces gastric secretion
Reduces gastric emptying Stimulates insulin release from pancreas |
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Where is vasoactive intestinal peptide (VIP) produced?
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Duodenal endocrine cells
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What is the stimulus for VIP release?
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Digestion products and acid in duodenum
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What are the effects of VIP?
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Promotes intestinal secretion
Reduces gastric motility and emptying |
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What does a VIPoma result in?
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Diarrhoea as too much VIP produced thus too much intestinal secretion
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What is the control centre for appetite?
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Hypothalamus
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What does electrical stimulation and destruction of the feeding centre cause?
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Electrical stimulation - hyperphagia
Destruction - lack of appetite and weight loss |
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What does electrical stimulation and destruction of the satiety centre cause?
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Electrical stimulation - aphagia
Destruction - continuous eating and obesity |
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What may the output of the hypothalamus be for feeding?
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Production of hormones from thyroid, adrenal, pancreas
Higher centres in brain and motor centre - for search for food |
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What is an anorexigenic agent to the hypothalamus?
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Causes decreased feeding
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What is an orexigenic agent?
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Causes increased feeding
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What is a hypothalamic neuropeptide influencing a stimulated appetite?
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Neuropeptide Y (NPY)
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What is a hypothalamic neuropeptide influencing a reduced appetite?
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Melanocyte-stimulating hormone (MSH)
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What are the receptors for melanocyte-stimulating hormone called?
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Melanocortin
5 subtypes = MCR-1 etc. |
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What are the 3 types of input to the hypothalamus for feeding/satiety?
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Mechanical
Chemical External |
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GIve an example of a mechanical input
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Distension of stomach or intestinal wall
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Give examples of chemical inputs
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Plasma concentrations of glucose, amino acids, fats, hormones etc.
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Give examples of external inputs
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Sight, smell, taste
Ambient temperature |
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Where is ghrelin produced?
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Gastric epithelium
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What may stimulate ghrelin production?
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Starvation
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How does ghrelin stimulate the feeding centre?
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Excitatory stimulation of neuropeptide-Y (NPY)-containing neurones in arcuate nucleus in hypothalamus
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How does the vagus nerve affect satiety?
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Stretch receptors activate afferent fibres in vagus nerve to satiety centre - inhibits food intake
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How does CCK affect satiety?
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Short-lived effect
May inhibit NPY hormones in arcuate nucleus in hypothalamus directly May affect sensory receptors in intestine which send impulses via vagus nerve to hypothalamus |
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How does peptide YY affect satiety?
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Small intestine and large intestine
Direct influence on hypothalamus and vagus nerve |
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How does insulin affect satiety?
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Similar to CCK and peptide YY
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What is DIRLOPATIDE (slentrol) used for?
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Promotes release of peptide YY, promotes satiety, used for weight loss in dogs
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How does the concentration of glucose (and some other metabolites) in the blood affect the firing of neurones in the feeding and satiety centre?
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High concentration = increase of firing neurones in satiety centre, decrease of firing neurones in feeding centre
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How do the levels of adipose tissue affect appetite?
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Leptin, peptide hormone stored in adipose tissue, released from adipocytes when weight is gained and crosses blood-brain barrier in order to reduce appetite and increase metabolism
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What does leptin affect?
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Stimulates MSH-neurones, inhibits NPY-neurones
Increased sympathetic NS - increased metabolism Decreased insulin secretion |
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Leptin resistance may lead to
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obesity
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